Albert Rimola, Stefano Ferrero, Aurèle Germain, Marta Corno and Piero Ugliengo: Computational Surface Modelling of Ices and Minerals of Interstellar Interest—Insights and Perspectives; Minerals 2021, 11(1), 26; https://doi.org/10.3390/min11010026

Abstract

The universe is molecularly rich, comprising from the simplest molecule (H2) to complex organic molecules (e.g., CH3CHO and NH2CHO), some of which of biological relevance (e.g., amino acids). This chemical richness is intimately linked to the different physical phases forming Solar-like planetary systems, in which at each phase, molecules of increasing complexity form. Interestingly, synthesis of some of these compounds only takes place in the presence of interstellar (IS) grains, i.e., solid-state sub-micron sized particles consisting of naked dust of silicates or carbonaceous materials that can be covered by water-dominated ice mantles. Surfaces of IS grains exhibit particular characteristics that allow the occurrence of pivotal chemical reactions, such as the presence of binding/catalytic sites and the capability to dissipate energy excesses through the grain phonons. The present know-how on the physicochemical features of IS grains has been obtained by the fruitful synergy of astronomical observational with astrochemical modelling and laboratory experiments. However, current limitations of these disciplines prevent us from having a full understanding of the IS grain surface chemistry as they cannot provide fundamental atomic-scale of grain surface elementary steps (i.e., adsorption, diffusion, reaction and desorption). This essential information can be obtained by means of simulations based on computational chemistry methods. One capability of these simulations deals with the construction of atom-based structural models mimicking the surfaces of IS grains, the very first step to investigate on the grain surface chemistry. This perspective aims to present the current state-of-the-art methods, techniques and strategies available in computational chemistry to model (i.e., construct and simulate) surfaces present in IS grains. Although we focus on water ice mantles and olivinic silicates as IS test case materials to exemplify the modelling procedures, a final discussion on the applicability of these approaches to simulate surfaces of other cosmic grain materials (e.g., cometary and meteoritic) is given.

Gianluca Grimaldi and Bruno Ehrler: AI et al.: Machines Are About to Change Scientific Publishing Forever;   ACS Energy Lett. 2023, 8, 1, 878–880 (https://doi.org/10.1021/acsenergylett.2c02828)

Introduction

Artificial intelligence (AI)-powered text generation will change scientific publishing fundamentally. In the past year, multiple AI systems have showcased production of visual and textual content increasingly indistinguishable from human-generated work, creating almost overnight new possibilities for intellectual workers, and at the same time raising similarly potent concerns. While artists and journalists are more evidently at the forefront of this incipient revolution, it is not hard to imagine a researcher looking away from the frustratingly sparse draft of a research article and wondering: “Could a machine write it for me?” (Figure 1). This question might have passed for a flight of fancy until recently, as machine-generated scientific arguments were easily distinguishable from human output, and paper-generating software mainly highlighted the permeability of the peer-review process to nonsensical papers. (1) However, these technologies have progressed so rapidly that we have likely entered a new phase, one in which machine-generated text can be integrated in human-generated scientific articles in a seamless fashion. To help illustrate the point in concrete terms, let’s directly ask one of the involved parties…

Junxian Liu, Ziyun Wang, Liangzhi Kou, and Yuantong Gu : Mechanism Exploration and Catalyst Design for Hydrogen Evolution Reaction Accelerated by Density Functional Theory Simulations;  ACS Sustainable Chem. Eng. 2023, 11, 2, 467–481 (https://doi.org/10.1021/acssuschemeng.2c05212)

Abstract

Electrocatalytic and photocatalytic water splittings for hydrogen production are sustainable technologies to potentially meet global energy demands without environmental pollution, which however highly depend on efficient and cost-effective catalysts. van der Waals layered materials are promising candidates for catalytic applications because of their unique layered structures and exciting electrical and optical properties. This perspective gives a brief overview of the recent applications of layered materials in electrocatalytic and photocatalytic hydrogen evolution reactions (HERs) from theoretical views. The roles of density functional theory (DFT) simulations in the explorations of layered HER catalysts are highlighted, including rationalizing the experimental findings and designing new catalysts. In the end, future research directions for accelerating the discoveries of HER catalysts are provided.

Hefei Li,  Haobo Li,   Pengfei Wei,   Yi Wang,   Yipeng Zang,   Dunfeng Gao,   Guoxiong Wang , and  Xinhe Bao : Tailoring acidic microenvironments for carbon-efficient CO2 electrolysis over a Ni–N–C catalyst in a membrane electrode assembly electrolyzer; Energy & Environmental Science (https://doi.org/10.1039/D2EE03482D)

Abstract

CO2 electrolysis converting CO2 into valuable fuels and chemicals powered by renewable electricity shows great promise for practical applications. However, it suffers from low energy efficiency and carbon efficiency due to severe carbon loss in alkaline and neutral electrolytes. Here we present a carbon-efficient CO2 electrolysis strategy using a zero-gap acidic membrane electrode assembly electrolyzer. The microenvironments of a Ni–N–C catalyst (such as local concentrations of H+/K+ and CO2) are turned by optimizing the anolyte composition (pH, K+) and input CO2 pressure. Under optimal conditions, acidic CO2 electrolysis over the Ni–N–C catalyst achieves a CO faradaic efficiency of 95% at a total current density of 500 mA cm−2, corresponding to a CO production rate as high as 13 mL min−1. An energy efficiency of 45% for CO production is obtained at pH 0.5 and the CO2 loss is reduced by 86% at 300 mA cm−2, compared to alkaline CO2 electrolysis. Density functional theory calculations reveal that the co-existence of H+ and K+ plays a crucial role in stabilizing the initial *CO2 intermediate, resulting in enhanced CO formation.

Wenshu Zhou, Yanyan Liu, Dichao Wu, Limin Zhou, Gaoyue Zhang, Kang Sun, Baojun Li and  Jianchun Jiang: Biomass chitosan-derived Co-induced N-doped carbon nanotubes to support Mn3O4 as efficient electrocatalysts for rechargeable Zn–air batteries; Energy Fuels, 2023, (https://doi.org/10.1039/D3SE00051F)

Abstract

Exploring efficient and low-cost electrocatalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is extremely desirable for the commercial application of rechargeable Zn–air batteries. Herein, we developed a facile pyrolysis and hydrothermal method for in situ immobilizing Mn3O4 onto chitosan-deriving Co-induced N-doped carbon nanotubes (Mn3O4/NCNTs@Co). The obtained Mn3O4/NCNTs@Co nanohybrid showed excellent activity for oxygen-reversible electrocatalysis with a half-wave potential (E1/2) of 0.85 V and a potential of 1.53 V at 10 mA cm−2. Furthermore, a homemade zinc–air battery with Mn3O4/NCNTs@Co catalyst showed a high open-circuit voltage (OCV) of 1.46 V and excellent cycling stability of nearly 1100 cycles at 5 mA cm−2. The outstanding electrocatalytic activities are comparable to those with commercial noble metal catalysts, ascribed to the synergistic integration between the Co, Mn3O4, and conductive carbon matrix. This study provides a promising route for the scalable preparation of biomass-derived efficient metallic compound-carbon-based ORR/OER electrocatalysts.

Mária Jerigová, Mateusz Odziomek, and Nieves López-Salas: “We Are Here!” Oxygen Functional Groups in Carbons for Electrochemical Applications;  ACS Omega 2022, 7, 14, 11544–11554

(https://doi.org/10.1021/acsomega.2c00639)

Abstract

Heteroatom doping of carbon networks may introduce active functional groups on the surface of the material, induce electron density changes that alter the polarity of the carbon surface, promote the formation of binding sites for molecules or ions, or make the surface catalytically active for different reactions, among many other alterations. Thus, it is no surprise that heteroatom doping has become a well-established strategy to enhance the performance of carbon-based materials for applications ranging from water remediation and gas sorption to energy storage and conversion. Although oxygen functionalization is sometimes inevitable (i.e., many carbon precursors contain oxygen functionalities), its participation in carbon materials performance is often overlooked on behalf of other heteroatoms (mainly nitrogen). In this Mini-review, we summarize recent and relevant publications on the effect that oxygen functionalization has on carbonaceous materials performance in different electrochemical applications and some strategies to introduce such functionalization purposely. Our aim is to revert the current tendency to overlook it and raise the attention of the materials science community on the benefits of using oxygen functionalization in many state-of-the-art applications.

Qian Zhao, Hongshuai Yu, Liang Fu, Pengfei Wu, Yihu Li, Yixin Li, Dan Sun, Haiyan Wang, and Yougen Tang:  Electrolytes for aluminum–air batteries: advances, challenges, and applications; Energy Fuels, 2023 https://doi.org/10.1039/D2SE01744J

Abstract

Aluminum–air batteries (AABs) are attracting increased attention because of their high energy density, low cost, and excellent security. Nonetheless, the commercialization process is hindered by two major hurdles, i.e., anode polarization and self-corrosion. The former impedes the electrochemical reaction, resulting in a large gap between the actual potential and the theoretical value. And the latter will consume the Al anode to produce H2, which seriously impairs the specific capacity and safety of the battery. Since the electrolyte is a key component connecting the cathode and anode by ion transmission, the regulation of electrolytes is an effective way to ameliorate these two issues. This review summarizes recent progress in the research and development of electrolytes for primary AABs, including aqueous electrolytes, non-aqueous electrolytes and solid-state electrolytes. The working mechanisms and underlying design strategies of different electrolytes are concluded. And then we discuss their advantages and disadvantages, based on which the application prospects of different electrolytes are especially presented to facilitate further research and development of electrolytes for practical AABs.

Qing Jin, Lei Tao, Yiming Feng, Dawei Xia, Glenn Allen Spiering, Anyang Hu, Robert Moore, Feng Lin, and Haibo Huang: Agricultural Wastes for Full-Cell Sodium-Ion Batteries: Engineering Biomass Components to Maximize the Performance and Economic Prospects; ACS Sustainable Chem. Eng. 2023, 11, 2, 536–546 (https://doi.org/10.1021/acssuschemeng.2c04750)

Abstract

Lignin is one of the most abundant biopolymers in nature. Although lignin-derived hard carbon (L-HC) has potential to be used as a sodium-ion battery (SIB) anode but is limited by its poor electrochemical performance. In nature, lignin normally coexists with cellulose and hemicellulose in agricultural biomass, and studies have applied different agricultural biomasses to make SIB anodes; however, the underlying mechanism, especially the functionality of each component, is still unclear. In this study, we aim to combine lignin with cellulose and/or hemicellulose to produce hard carbons with outstanding electrochemical performance and low cost, and more importantly, unveil the underlying mechanisms. We found that the poor electrochemical performance of L-HC was mainly due to its large surface area with high amount of oxygen-containing functional groups and its unique physical structure that inhibit effective Na diffusion. Combining lignin with either cellulose or hemicellulose led to significantly improved electrochemical performance of the resulting hard carbon, with cellulose mainly contributing to the increase of capacity and hemicellulose mainly contributing to the stability of capacity during cycling and at high current density. Based on the comprehensive consideration of both electrochemical performance (half and full cells) and economic perspectives, lignin combined with cellulose showed great potential. Our study shed light on the contributions of each major biomass component on physical and electrochemical properties of resulting hard carbon and designed a unique way to improve L-HC.

Hongcai Su, Yanjun Hu, Hongyu Feng, Lingjun Zhu, and Shurong Wang:   Efficient H2 Production from PET Plastic Wastes over Mesoporous Carbon-Supported Ru-ZnO Catalysts in a Mild Pure-Water System  ;ACS Sustainable Chem. Eng. 2023, 11, 2, 578–586 (https://doi.org/10.1021/acssuschemeng.2c05062)

Abstract

The massive consumption of plastic is posing severe pollution-related challenges globally. As the most abundant polyester plastic, polyethylene terephthalate (PET) waste represents a largely untapped resource for generating chemicals and fuels. However, the current widespread use of alkali/organic solvents and the complex processing of PET reduce its environmental sustainability. Herein, a novel and simple one-pot strategy was first reported for the catalytic conversion of PET into H2 fuel and terephthalic acid in a pure-water system under mild conditions. A high H2 yield of 19.97 mol/kgPET and carbon conversion efficiency of 97.22% were obtained for the Ru-5ZnO/mesoporous carbon (MEC) catalyst at a low temperature of 250 °C. This process proceeds through tandem catalytic reactions with an initial PET depolymerization step, followed by in situ aqueous phase reforming (APR) of ethylene glycol of Ru. Remarkably, ZnO inhibited the deactivation of Ru/MEC in the PET depolymerization stage, causing an increase in H2 production from the in situ APR stage. Importantly, this strategy was successfully applied to four types of real-world PET waste and their mixtures, demonstrating that it has considerable potential in practical applications and provides a sustainable and clean solution to the plastic waste problem.

Xiaoxia Liu, Yangyang Wang, Ronghao Liu, Ping Lv, Wenfeng Xue, Jinxin Guo, Huiying Wei, and  Yanzhao Yang: Selective and Efficient Gold Extraction from E-Waste by Pyrrolidinium-Based Ionic Liquids with Various N-Substituents ; ACS Sustainable Chem. Eng. 2023, 11, 2, 638–648 (https://doi.org/10.1021/acssuschemeng.2c05455)

Abstract

With environmental problems and a shortage of resources, it is urgent to recover gold from electronic waste (e-waste). Meanwhile, it is necessary to explore the relationships between the structures and extraction performances of ionic liquids (ILs) to further improve the extraction capacities of ILs for gold. Herein, three pyrrolidinium-based ILs with various N-substituents were synthesized for solvent-free extraction of Au(III). The three pyrrolidinium-based ILs exhibited ultrahigh extraction capacities for Au(III) with the order of [Pyr-EA][NTf2] (524.6 mg·g–1) > [Pyr-Bu][NTf2] (457.3 mg·g–1) > [Pyr-C2OC2][NTf2] (403.5 mg·g–1). The effects of N-substituents on extraction performances were quantitatively investigated by electrostatic potential (ESP) and quantitative NMR. Among them, the ester group (−COOR) is the most beneficial to the extraction process, which is associated with an increased ESP value and boosted hydrophobicity. Notably, [Pyr-EA][NTf2] displayed outstanding selectivity in multimetal solutions; especially, it could selectively and efficiently extract Au(III) from the actual CPU. Furthermore, [Pyr-EA][NTf2] possesses significant reuseability and can maintain superior extraction efficiency of 84.3% after five cycles. These excellent performances together with low cost ($0.44·g–1 [Pyr-EA][NTf2]) and considerable profit ($29.72·g–1 

[Pyr-EA][NTf2]) confirmed that [Pyr-EA][NTf2] is a promising prospect for sustainable recovery of gold from e-waste.

Yijie Wang, Juan An, Lu Qi, Yurui Xue, Guoxing Li, Qiang Lyu, Wenlong Yang, and Yuliang Li: Synthesis of Crystalline Phosphine-Graphdiyne with Self-Adaptive p−π Conjugation,  J. Am. Chem. Soc. 2023, 145, 2, 864–872, https://doi.org/10.1021/jacs.2c09209

Abstract

“Dynamic” behavior materials with high surface activity and the ability of chemical bond conversion are the frontier materials in the field of renewable energy. The outstanding feature of these materials is that they have adaptive electronic properties that external stimuli can adjust. An original discovery in a new crystalline two-dimensional phosphine-graphdiyne (P-GDY) material is described here. Although the p−π conjugation of most trivalent phosphorus π-systems is insignificant because of the pyramidal configuration, the lone pair electrons of phosphorus atoms participate strongly in the delocalization under the influence of the interlayer van der Waals forces in P-GDY. Due to the dynamically reversible nature of noncovalent interactions (p−π conjugation), P-GDY exhibits a specific adaptive behavior and realizes the responsive reversible transport of a lithium ion by regulating p−π interactions. Our findings would provide the potential to develop a new family of responsive materials with tunable structures.

Zhengyi Wan, Yeguang Fang, Ziao Liu, Joseph S. Francisco, and Chongqin Zhu:  Mechanistic Insights into the Reactive Uptake of Chlorine Nitrate at the Air–Water Interface; J. Am. Chem. Soc. 2023, 145, 2, 944–952 (https://doi.org/10.1021/jacs.2c09837)

Abstract

It is well-known that the aqueous-phase processing of chlorine nitrate (ClONO2) plays a crucial role in ozone depletion. However, many of the physical and chemical properties of ClONO2 at the air–water interface or in bulk water are unknown or not understood on a microscopic scale. Here, the solvation and hydrolysis of ClONO2 at the air–water interface and in bulk water at 300 K were investigated by classical and ab initio molecular dynamics (AIMD) simulations combined with free energy methods. Our results revealed that ClONO2 prefers to accumulate at the air–water interface rather than in the bulk phase. Specifically, halogen bonding interactions (ClONO2)Cl···O(H2O) were found to be the predominant interactions between ClONO2 and H2O. Moreover, metadynamics-biased AIMD simulations revealed that ClONO2 hydrolysis is catalyzed at the air–water interface with an activation barrier of only ∼0.2 kcal/mol; additionally, the difference in free energy between the product and reactant is only ∼0.1 kcal/mol. Surprisingly, the near-barrierless reaction and the comparable free energies of the reactant and product suggested that the ClONO2 hydrolysis at the air–water interface is reversible. When the temperature is lowered from 300 to 200 K, the activation barrier for the ClONO2 hydrolysis at the air–water interface is increased to ∼5.4 kcal/mol. These findings have important implications for the interpretation of experiments.

Xiaoyi Xu, Shuoqing Zhang, Kai Xu, Hongzheng Chen, Xiulin Fan, and Ning Huang: Janus Dione-Based Conjugated Covalent Organic Frameworks with High Conductivity as Superior Cathode Materials;   J. Am. Chem. Soc. 2023, 145, 2, 1022–1030 (https://doi.org/10.1021/jacs.2c10509)

Abstract

The development of conductive covalent organic frameworks (COFs) with high stability is desirable for the practical applications in optoelectronics and energy storage. Herein, we developed a new kind of Janus dione-based COF, which is fully sp2 carbon-conjugated through the connection by olefin units. The electrical conductivity and carrier mobility reached up to 10–3 S cm–1 and 7.8 cm2 V–1 s–1, respectively. In addition, these COFs are strongly robust against various harsh conditions. The well-ordered two-dimensional crystalline structures, excellent porosity, high conductivity, and abundant redox-active carbonyl units render these COFs serviceable as high-performance cathode materials in lithium-ion batteries. It is worth noting that TFPPy-ICTO-COF exhibits a capacity of up to 338 mAh g–1 at a discharge rate of 0.1 C, which sets a new capacity record among COF-based lithium-ion batteries. Its capacity retention was as high as 100% even after 1000 cycles, demonstrating the remarkable stability of these Janus dione-based COF materials. This work not only expands the diversity of olefin-linked COFs but also makes a new breakthrough in energy storage.

Haidong Bian, Wubin Wu, Yuanyi Zhu, Chi Him Tsang, Yulin Cao, Jingyou Xu, Xingan Liao, Zhouguang Lu, Xiao-Ying Lu, Chen Liu, and Zheming Zhang: Waste to Treasure: Regeneration of Porous Co-Based Catalysts from Spent LiCoO2 Cathode Materials for an Efficient Oxygen Evolution Reaction; ACS Sustainable Chem. Eng. 2023, 11, 2, 670–678 (https://doi.org/10.1021/acssuschemeng.2c05534)

Abstract

The increasing demand for portable electronic devices and electric vehicles (EVs) has triggered the rapid growth of the rechargeable Li-ion battery (LIB) market. However, in the near future, it is predicted that a large amount of spent LIBs will be scrapped, imposing huge pressure on environmental protection and resource reclaiming. The effective recycling or regeneration of the spent LIBs not only relieves the environmental burdens but also avoids the waste of valuable metal resources. Herein, a porous Co9S8/Co3O4 heterostructure is successfully synthesized from the spent LiCoO2 (LCO) cathode materials via a conventional hydrometallurgy and sulfidation process. The fabricated Co9S8/Co3O4 catalyst exhibits high catalytic activity toward oxygen evolution reaction (OER) in an alkaline solution, with an overpotential of 274 mV to achieve the current density of 10 mA cm–2 and a Tafel slope of 48.7 mV dec–1. This work demonstrates a facile regeneration process of Co-based electrocatalysts from the spent LiCoO2 cathode materials for efficient oxygen evolution reaction.

Sajal Sen, Fumitaka Ishiwari, Ramandeep Kaur, Masatoshi Ishida, Debmalya Ray, Koichi Kikuchi, Takehiko Mori, Steffen Bähring, Vincent M. Lynch, Akinori Saeki, Dirk M. Guldi, Jonathan L. Sessler, and Atanu Jana: Supramolecular Recognition within a Nanosized “Buckytrap” That Exhibits Substantial Photoconductivity;  J. Am. Chem. Soc. 2023, 145, 2, 1031–1039 (https://doi.org/10.1021/jacs.2c10555)

Abstract

We report here a nanosized “buckytrap”, 1, constructed from two bis-zinc(II) expanded-TTF (exTTF) porphyrin subunits. Two forms, 1a and 1b, differing in the axial ligands, H2O vs tetrahydrofuran (THF), were isolated and characterized. Discrete host–guest inclusion complexes are formed upon treatment with fullerenes as inferred from a single-crystal X-ray structural analyses of 1a with C70. The fullerene is found to be encapsulated within the inner pseudohexagonal cavity of 1a. In contrast, the corresponding free-base derivative (2) was found to form infinite ball-and-socket type supramolecular organic frameworks (3D-SOFs) with fullerenes, (2•C60)n or (2•C70)n. This difference is ascribed to the fact that in 1a and 1b the axial positions are blocked by a H2O or THF ligand. Emission spectroscopic studies supported a 1:1 host–guest binding stoichiometry, allowing association constants of (2.0 ± 0.5) × 104 M–1 and (4.3 ± 0.9) × 104 M–1 to be calculated for C60 and C70, respectively. Flash-photolysis time-resolved microwave conductivity (FP-TRMC) studies of solid films of the Zn-complex 1a revealed that the intrinsic charge carrier transport, i.e., pseudo-photoconductivity (ϕ∑μ), increases upon fullerene inclusion (e.g., ϕ∑μ = 1.53 × 10–4 cm2 V–1 s–1 for C60⊂(1a)2 and ϕ∑μ = 1.45 × 10–4 cm2 V–1 s–1 for C70⊂(1a)2 vs ϕ∑μ = 2.49 × 10–5 cm2 V–1 s–1 for 1a) at 298 K. These findings provide support for the notion that controlling the nature of self-assembly supramolecular constructs formed from exTTF-porphyrin dimers through metalation or choice of fullerene can be used to regulate key functional features, including photoconductivity.

Qi Chen, Olugbenga Adeniran, Zhen-Fei Liu, Zhongyue Zhang, and Kunio Awaga:  Graphite-like Charge Storage Mechanism in a 2D π–d Conjugated Metal–Organic Framework Revealed by Stepwise Magnetic Monitoring;  J. Am. Chem. Soc. 2023, 145, 2, 1062–1071 (https://doi.org/10.1021/jacs.2c10650)

Abstract

Quasi-two-dimensional (2D) fully π–d conjugated metal–organic frameworks (MOFs) have been widely employed as active materials of secondary batteries; however, the origin of their high charge storage capacity is still unknown. Some reports have proposed a mechanism by assuming the formation of multiple radicals on one organic ligand, although there is no firm evidence for such a mechanism, which would run counter to the resonance theory. In this work, we utilized various magnetometric techniques to monitor the formation and concentration of paramagnetic species during the electrochemical process of 2D π–d conjugated Cu-THQ MOF (THQ = tetrahydroxy-1,4-benzoquinone). The spin concentration of the fully reduced (discharged 1.5 V) electrode was estimated to be around only 0.1 spin-1/2 per CuO4 unit, which is much lower than that of the expected “diradical” form. More interestingly, a significant elevation of the temperature-independent paramagnetic term was simultaneously observed, which indicates the presence of delocalized π electrons in this discharged state. Such results were corroborated by first-principles density functional theory calculations and the electrochemically active density of states, which reveal the microscopic mechanism of the charge storage in the Cu-THQ MOF. Hence, a graphite-like charge storage mechanism, where the π-electron band accepts/donates electrons during the charge/discharge process, was suggested to explain the excessive charge storage of Cu-THQ. This graphite-like charge storage mechanism revealed by magnetic studies can be readily generalized to other π–d conjugated MOFs.

Maximilian Quentmeier, Bernhard Schmid, Hermann Tempel, Hans Kungl, and Rüdiger-A. Eichel: Toward a Stackable CO2-to-CO Electrolyzer Cell Design─Impact of Media Flow Optimization;  ACS Sustainable Chem. Eng. 2023, 11, 2, 679–688 (https://doi.org/10.1021/acssuschemeng.2c05539)

Abstract

Aqueous CO2-to-CO electrolysis is a promising technology for closing the carbon cycle and defossilizing industrial processes. Considering the technological readiness, consensus has been achieved about using silver as a stable and selective electrocatalyst for the CO2-to-CO reduction reaction in aqueous electrolyte. On the other hand, challenges such as media flow management, component stability, and force distribution are still associated with improving the process performance and developing a stackable cell concept to meet industrially relevant levels. We therefore report on a promising stack concept with continuous flowcells operated with gas diffusion electrodes (GDEs). To enhance the CO2-to-CO conversion efficiency, dedicated media flow chambers were developed on two levels. In the gas chamber, which touches the GDE from the far side of the anode, the feed gas flow and distribution over the GDE were controlled by introducing various gas path architectures in a modular flowcell. In addition, an ionically conductive spacer was implemented in the catholyte chamber, which is adjacent to the opposite side of the GDE. The effect of these modifications on the cell voltage, selectivity, and overall conversion was investigated at 100 mA/cm2 with varying CO2 feed gas flow and concentration. Noteworthy, an optimized feed gas distribution generated an increase of the Faraday efficiency for CO under reduced CO2 supply. Furthermore, the implementation of the spacer enhanced the process stability by suppressing gas-bubble-induced noise in the cell voltage measurements. By functioning as support structures to the GDE, the combined modifications provided the cell with mechanical integrity and allowed an ionic and electric contact over the full active cell area, which is required for both stacking and upscaling of the cell. The corresponding performance was demonstrated by a two-cell short-stack.

Arjun Halder, David C. Bain, Julia Oktawiec, Matthew A. Addicoat, Stavrini Tsangari, José J. Fuentes-Rivera, Tristan A. Pitt, Andrew J. Musser, and Phillip J. Milner:  Enhancing Dynamic Spectral Diffusion in Metal–Organic Frameworks through Defect Engineering ; J. Am. Chem. Soc. 2023, 145, 2, 1072–1082 (https://doi.org/10.1021/jacs.2c10672)

Abstract

The crystal packing of organic chromophores has a profound impact on their photophysical properties. Molecular crystal engineering is generally incapable of producing precisely spaced arrays of molecules for use in photovoltaics, light-emitting diodes, and sensors. A promising alternative strategy is the incorporation of chromophores into crystalline metal–organic frameworks (MOFs), leading to matrix coordination-induced emission (MCIE) upon confinement. However, it remains unclear how the precise arrangement of chromophores and defects dictates photophysical properties in these systems, limiting the rational design of well-defined photoluminescent materials. Herein, we report new, robust Zr-based MOFs constructed from the linker tetrakis(4-carboxyphenyl)ethylene (TCPE4–) that exhibit an unexpected structural transition in combination with a prominent shift from green to blue photoluminescence (PL) as a function of the amount of acid modulator (benzoic, formic, or acetic acid) used during synthesis. Time-resolved PL (TRPL) measurements provide full spectral information and reveal that the observed hypsochromic shift arises due to a higher concentration of linker substitution defects at higher modulator concentrations, leading to broader excitation transfer-induced spectral diffusion. Spectral diffusion of this type has not been reported in a MOF to date, and its observation provides structural information that is otherwise unobtainable using traditional crystallographic techniques. Our findings suggest that defects have a profound impact on the photophysical properties of MOFs and that their presence can be readily tuned to modify energy transfer processes within these materials.

Chunyang Dong, Maya Marinova, Karima Ben Tayeb, Olga V. Safonova, Yong Zhou, Di Hu, Sergei Chernyak, Massimo Corda, Jérémie Zaffran, Andrei Y. Khodakov, and Vitaly V. Ordomsky:  Direct Photocatalytic Synthesis of Acetic Acid from Methane and CO at Ambient Temperature Using Water as Oxidant; J. Am. Chem. Soc. 2023, 145, 2, 1185–1193 (https://doi.org/10.1021/jacs.2c10840)

Abstract

Direct functionalization of methane selectively to value-added chemicals is still one of the main challenges in modern science. Acetic acid is an important industrial chemical produced nowadays by expensive and environmentally unfriendly carbonylation of methanol using homogeneous catalysts. Here, we report a new photocatalytic reaction route to synthesize acetic acid from CH4 and CO at room temperature using water as the sole external oxygen source. The optimized photocatalyst consists of a TiO2 support and ammonium phosphotungstic polyoxometalate (NPW) clusters anchored with isolated Pt single atoms (Pt1). It enables a stable synthesis of 5.7 mmol·L–1 acetic acid solution in 60 h with the selectivity over 90% and 66% to acetic acid on liquid-phase and carbon basis, respectively, with the production of 99 mol of acetic acid per mol of Pt. Combined isotopic and in situ spectroscopy investigation suggests that synthesis of acetic acid proceeds via a photocatalytic oxidative carbonylation of methane over the Pt1 sites, with the methane activation facilitated by water-derived hydroxyl radicals.

Taiping Hu, Jianxin Tian, Fuzhi Dai, Xiaoxu Wang, Rui Wen, and Shenzhen Xu:  Impact of the Local Environment on Li Ion Transport in Inorganic Components of Solid Electrolyte Interphases ; J. Am. Chem. Soc. 2023, 145, 2, 1327–1333 https://doi.org/10.1021/jacs.2c11521)

Abstract

The spontaneously formed passivation layer, the solid electrolyte interphase (SEI) between the electrode and electrolyte, is crucial to the performance and durability of Li ion batteries. However, the Li ion transport mechanism in the major inorganic components of the SEI (Li2CO3 and LiF) is still unclear. Particularly, whether introducing an amorphous environment is beneficial for improving the Li ion diffusivity is under debate. Here, we investigate the Li ion diffusion mechanism in amorphous LiF and Li2CO3 via machine-learning-potential-assisted molecular dynamics simulations. Our results show that the Li ion diffusivity in LiF at room temperature cannot be accurately captured by the Arrhenius extrapolation from the high temperature (>600 K) diffusivities (difference of ∼2 orders of magnitude). We reveal that the spontaneous formation of Li–F regular tetrahedrons at low temperatures (<500 K) leads to an extremely low Li ion diffusivity, suggesting that designing an amorphous bulk LiF-based SEI cannot help with the Li ion transport. We further show the critical role of Li2CO3 in suppressing the Li–F regular tetrahedron formation when these two components of SEIs are mixed. Overall, our work provides atomic insights into the impact of the local environment on Li ion diffusion in the major SEI components and suggests that suppressing the formation of large-sized bulk-phase LiF might be critical to improve battery performance.

Marilia T. C. Martins-Costa and Manuel F. Ruiz-López:  Electrostatics and Chemical Reactivity at the Air–Water Interface ;  J. Am. Chem. Soc. 2023, 145, 2, 1400–1406, https://doi.org/10.1021/jacs.2c12089)

Abstract

It has been recently discovered that chemical reactions at aqueous interfaces can be orders of magnitude faster compared to conventional bulk phase reactions, but despite its wide-ranging implications, which extend from atmospheric to synthetic chemistry or technological applications, the phenomenon is still incompletely understood. The role of strong electric fields due to space asymmetry and the accumulation of ions at the interface has been claimed as a possible cause from some experiments, but the reorganization of the solvent around the reactive system should provide even greater additional electrostatic contributions that have not yet been analyzed. In this study, with the help of first-principles molecular dynamics simulations, we go deeper into this issue by a careful assessment of solvation electrostatics at the air–water interface. Our simulations confirm that electrostatic forces can indeed be a key factor in rate acceleration compared to bulk solution. Remarkably, the study reveals that the effect cannot simply be attributed to the magnitude of the local electric field and that the fluctuations of the full electrostatic potential resulting from unique dynamical behavior of the solvation shells at the interface must be accounted for. This finding paves the way for future applications of the phenomenon in organic synthesis, especially for charge transfer or redox reactions in thin films and microdroplets.

Katelyn J. Baumler, Lucas T. Alameda, Rowan R. Katzbaer, Sarah K. O’Boyle, Robert W. Lord, and Raymond E. Schaak:  Introducing Porosity into Refractory Molybdenum Boride through Controlled Decomposition of a Metastable Mo–Al–B Precursor;  J. Am. Chem. Soc. 2023, 145, 2, 1423–1432 (https://doi.org/10.1021/jacs.2c12496)

Abstract

The high temperatures typically required to synthesize refractory compounds preclude the formation of high-energy morphological features, including nanoscopic pores that are beneficial for applications, such as catalysis, that require higher surface areas. Here, we demonstrate a low-temperature multistep pathway to engineer mesoporosity into a catalytic refractory material. Mesoporous molybdenum boride, α-MoB, forms through the controlled thermal decomposition of nanolaminate-containing sheets of the metastable MAB (metal–aluminum–boron) phase Mo2AlB2 and amorphous alumina. Upon heating, the Mo2AlB2 layers of the Mo2AlB2–AlOx nanolaminate, which is derived from MoAlB, begin to bridge and decompose, forming inclusions of alumina in a framework of α-MoB. The alumina can be dissolved in aqueous sodium hydroxide in an autoclave, forming α-MoB with empty and accessible pores. Statistical analysis of the morphologies and dimensions of the pores reveals a correlation with grain size, which relates to the pathway by which the alumina inclusions form. The transformation of Mo2AlB2 to α-MoB is topotactic due to crystal structure relationships, resulting in a high density of stacking faults that can be modeled to account for the observed experimental diffraction data. Porosity was validated by comparing surface areas and demonstrating catalytic viability for the hydrogen evolution reaction.

Shailesh Pandey, Vimal Chandra Srivastava, and Vimal Kumar:  High-Ash Low-Rank Coal Gasification: Process Modeling and Multiobjective Optimization ; ACS Eng. Au 2022, XXXX, XXX, XXX-XXX (https://doi.org/10.1021/acsengineeringau.2c00034)

Abstract

The diversification of coal for its sustainable utilization in producing liquid transportation fuel is inevitable in countries with huge coal reserves. Gasification has been contemplated as one of the most promising thermochemical routes to convert coal into high-quality syngas, which can be utilized to produce liquid hydrocarbons through catalytic Fischer–Tropsch (F-T) synthesis. Liquid transportation fuel production through coal gasification could help deal with environmental challenges and renewable energy development. The present study aims to develop an equilibrium model of a downdraft fixed-bed gasifier using Aspen Plus simulator to predict the syngas compositions obtained from the gasification of high-ash low-rank coal at different operating conditions. Air is used as a gasifying agent in the present study. The model validation is done using published experimental and simulation results from previous investigations. The sensitivity analysis is done to observe the influence of the major operating parameters, such as equivalence ratio (ER), gasification temperature, and moisture content (MC), on the performance of the CL-RMC concerning syngas generation. The gasification performance of CL-RMC is analyzed by defining various performance parameters such as syngas composition, hydrogen-to-carbon monoxide (H2/CO), molar ratio, syngas yield (YSyngas), the lower heating value of syngas (LHVSyngas), cold gas efficiency (CGE), and carbon conversion efficiency (CCE). The combined effects of the major operating parameters are studied through the response surface methodology (RSM) using the design of experiments. The optimized condition of the major operational parameters is determined for a target value of a H2/CO molar ratio of 1 and the maximum CGE and CCE using the multiobjective optimization approach. The high-degree accurate regression model equations were generated for the H2/CO molar ratio, CGE, and CCE using the variance analysis (ANOVA) tool. The optimal conditions of the major operating parameters, i.e., ER, gasification temperature, MC for the H2/CO molar ratio of 1, and the maximum CGE and CCE, are found to be 0.5, 655 °C, and 16.36 wt %, respectively. The corresponding optimal values of CGE and CCE are obtained as 22 and 16.36%, respectively, with a cumulative composite desirability value of 0.7348. The findings of the present investigation can be decisive for future developmental projects in countries concerning the utilization of high-ash low-rank coal in liquid fuel production through the gasification route.

Wim Buijs: CO2 Capture with PEI: A Molecular Modeling Study of the Ultimate Oxidation Stability of LPEI and BPEI;  ACS Eng. Au 2023, 3, 1, 28–36 (https://doi.org/10.1021/acsengineeringau.2c00033)

Abstract

Amine resins are frequently studied to capture CO2 from industrial emission sources and air. Polyethylene imine (PEI) is a typical example showing relatively high CO2 uptake and not too energy demanding desorption of CO2. For practical application, its oxidation stability is of great importance. In this DFT study, the ultimate oxidation stability of the two forms of PEI, linear PEI (LPEI) and branched PEI (BPEI), is investigated. First, the oxidation stability order for amines was determined using small amine clusters: primary > secondary > tertiary amines. Using LPEI and BPEI structure-related clusters, it turned out that under optimal conditions, the formation of α-amino hydroperoxide of PEI is the rate-determining step. Optimal conditions are the total absence of initiators like transition-metal ions, NOx, O3, or hydrocarbons and the presence of H2O and CO2. All computational results are in line with experimental results.

Hao-Jie Chen and Qiang Sun: “Ship-In-a-Bottle” Strategy to Construct Polymeric Sulfur Inside Mesoporous Carbon for High-Performance Lithium–Sulfur Batteries;  ACS Sustainable Chem. Eng. 2023, 11, 2, 777–784 (https://doi.org/10.1021/acssuschemeng.2c06353)

Abstract

Polymeric sulfur was synthesized via an interfacial polycondensation reaction and incorporated inside the mesopores of the mesoporous carbons through the “ship-in-a-bottle” strategy for lithium–sulfur batteries. Based on the excellent physical properties of the carbon host and the C–S bonds in the polymer, the polymeric sulfur composite cathode exhibited a strong confined effect on polysulfides, thus inhibiting the shuttle effect and delivering a reversible discharge capacity of 846 mA h g–1 at 0.5 C over 200 cycles and of 813 mA h g–1 at 1 C for 200 cycles with a capacity decay rate of 0.04% per cycle. Even at a rate of 2 C, the obtained polymeric sulfur-based cathode also maintained a capacity of 535 mA h g–1 after 600 cycles with a decay rate of only 0.04% per cycle.

Yi Rong, Zhengyi Lu, Chao Jin, Yadong Xu, Lin Peng, Ruhua Shi, Tianyi Gu, Chengyi Lu, and Ruizhi Yang: Tailoring of Li/LATP-PEO Interface via a Functional Organic Layer for High-Performance Solid Lithium Metal Batteries;  ACS Sustainable Chem. Eng. 2023, 11, 2, 785–795  (https://doi.org/10.1021/acssuschemeng.2c06404)

Abstract

Surface functionalization is an effective strategy to reduce the chemical reactivity between a Li1.3Al0.3Ti1.7(PO4)3 (LATP) electrolyte and Li metal anode and optimize the interfacial contact of different components. Herein, sodium itaconate (SI) is introduced to modify the surfaces of LATP particles (LATP@SI) via a self-polymerizing process, and a composite solid electrolyte (CSE) composed of poly(ethylene oxide) (PEO) and LATP@SI is fabricated. Benefiting from the protection of the SI nanolayer, LATP demonstrates chemical compatibility with the Li metal anode, while the reduced surface energy renders a good dispersion of LATP in PEO. Furthermore, abundant carboxyl groups in SI can offer a bridge between LATP and PEO to accelerate Li transmission. As a result, the as-prepared PEO-LATP@SI-6 CSE exhibits a high ionic conductivity of 1.15 × 10+–4 S cm–1 at 30 °C and 1.20 × 10–3 S cm–1 at 60 °C, a wide electrochemical stable window beyond 5.0 V, an improved Li transference number of 0.41, and an optimized lithium compatibility over 1200 h with Li dendrite free. The as-assembled Li||PEO-LATP@SI-6 CSE||LiFePO+4 full battery delivers a high reversible capacity of 155 mAh g–1 and an outstanding capacity retention of 89% after 200 cycles. The Li||LiFePO4 pouch cell also successfully runs 50 cycles with a terminal discharge capacity of 116.6 mA h g–1. This study opens a new avenue to protect LATP. The developed surface functionalization technique promises a facile and efficient method for interfacial engineering to accelerate the practical application of LATP in solid-state lithium batteries.

François Larouche, Frédéric Voisard, Kamyab Amouzegar, Georges Houlachi, Patrick Bouchard, Ashok Vijh, and George P. Demopoulos: Kinetics, Mechanism, and Optimization Modeling of a Green LFP Delithiation Process Developed for Direct Recycling of Lithium-Ion Batteries;  Ind. Eng. Chem. Res. 2023, 62, 2, 903–915 (https://doi.org/10.1021/acs.iecr.2c03552)

Abstract

Orthorhombic LiFePO4 (LFP) offers highly reversible redox reactions, making it an attractive cathodic material for lithium-ion batteries. This electrochemical property was exploited to develop an environmentally benign selective lithium extraction process based on CO2 and hydrogen peroxide that can be applied to direct LFP recycling. The proof of concept of this green delithiation process was demonstrated in a previously published paper, while the process optimization and the establishment of the reaction kinetic mechanism are addressed in the current paper. First, the effects of solid to liquid ratio (S/L), temperature, CO2 pressure, and initial H2O2 to LFP molar ratio were studied through an orthogonal design of experiments. In the range of conditions studied and considering the objective of maximizing the S/L ratio, the optimal conditions are a temperature of 20 °C, a CO2 pressure of 2 atm, and a H2O2 to LFP molar ratio of 1.25. In addition, reaction kinetic models were used to determine the reaction mechanism. The activation energies obtained based on rate constants from shrinking core and Avrami models are 15.7 and 13.9 kJ mol–1, respectively. While these values reveal a mixed or diffusion-controlled heterogeneous reaction, the analysis of half-delithiated LFP particles under scanning–transmission electron microscopy revealed the reaction being controlled by nucleation rather than diffusion. In this context, the Avrami model that accounts for nucleation and growth in solid-state reactions proved the most appropriate. Further, the reaction mechanism is concluded to be limited by nucleation of FP phase within the body of LFP during the early reaction stage and to sequentially shift to the one-dimensional diffusion-limited crystallite growth regime. Finally, it is shown that CO2 acts as a buffering agent by neutralizing the LiOH formed by Fenton-like reactions between H2O2 and ferric iron in LFP.

Vahideh Elhami, Mark A. Hempenius, and Boelo Schuur: Crotonic Acid Production by Pyrolysis and Vapor Fractionation of Mixed Microbial Culture-Based Poly(3-hydroxybutyrate-co-3-hydroxyvalerate);  Ind. Eng. Chem. Res. 2023, 62, 2, 916–923 (https://doi.org/10.1021/acs.iecr.2c03791)

Abstract

Crotonic acid (CA) and trans-2-pentenoic acid (2-PA) can be obtained from renewable resources by pyrolysis of the bio-based poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer. In this study, direct pyrolysis of the PHBV-enriched biomass into CA and 2-PA was studied under an inert atmosphere and N2 carrier gas flow, aiming at obtaining high acid yields from mixed microbial cultures (MMCs). The highest yields of 80 ± 2% for CA and 67 ± 1% for 2-PA were obtained at conditions of 240 °C, 1 h, and 0.15 L/min nitrogen flow rate, corresponding to a mean hot vapor residence time of 20 s. A similar acid yield was achieved when the pyrolysis was performed under reduced pressure (150 mbar) instead of using nitrogen gas. The combined pyrolysis of extracted PHBV at 220 °C and 90 min with vapor fractionation by distillation resulted in yields of 81 and 92% for CA and 2-PA, respectively.

Bin Jiang, Rongwei Guo, Taotao Fu, Chunying Zhu, and Youguang Ma: Distribution and Mass Transfer of Gas–Liquid Two-Phase Flow in Comb-Shaped Microchannels;   Ind. Eng. Chem. Res. 2023, 62, 2, 924–935 (https://doi.org/10.1021/acs.iecr.2c03851)

Abstract

For gas–liquid two-phase flow in comb-shaped microchannels, operating conditions could change the flow pattern and the uniformity of flow distribution and further affect the mass transfer performance. In this study, the hydrodynamics and mass transfer of gas–liquid two-phase flow in comb-shaped microchannels are investigated. Four flow patterns are observed: single-phase or foam flow, slug-bubbly flow, slug flow, and compact slug flow. When the flow pattern is slug flow, the flow distribution and velocity distribution in the microchannel are ideal, and its mass transfer performance is close to that of a single microchannel. Before the appearance of slug flow, the uniformity of flow distribution and mass transfer performance are improved with the increase of the ratio of gas–liquid flow rate. After the appearance of slug flow, the uniformity of flow distribution and mass transfer performance are deteriorated with the increase of the ratio of gas–liquid flow rate.

Shaoxiong Fu, Yuan Zhang, Yuhan Bian, Jiahao Xu, Li Wang, and Guangchuan Liang: Effect of Fe3+ and/or PO43– Doping on the Electrochemical Performance of LiNi0.5Mn1.5O4 Cathode Material for Li-Ion Batteries;  Ind. Eng. Chem. Res. 2023, 62, 2, 1016–1028 (https://doi.org/10.1021/acs.iecr.2c04037)

Abstract

An Fe3+/PO43– codoped LiNi0.5Mn1.4667Fe0.02P0.0133O4 sample has been prepared by a coprecipitation–hydrothermal method followed by two-step calcination. A novel wet chemical route, using FeSO4 rather than Fe2(SO4)3 as the Fe3+ source and NaH2PO4 as the PO43– source, is adopted to obtain uniform codoping of Fe3+ and PO43– ions in a carbonate precursor according to the precipitation–dissolution–transformation mechanism. For comparison, Fe3+-doped and PO43–-doped samples have been also synthesized via the same route. The effects of Fe3+/PO43– codoping and single doping on the crystalline structure, morphology, and electrochemical performance of LiNi0.5Mn1.5O4 are investigated. Compared with pristine and single doped samples, the codoped sample shows better electrochemical performance, with a specific discharge capacity of 125.2 mAh g–1 at 10 C and a capacity retention rate of 85.9% after 200 cycles at 1 C, under the synergy of Fe3+/PO43– codoping, including enhanced crystallinity, decreased Mn3+ content, significantly reduced primary particle size and secondary agglomeration, as well as the appearance of (110) surfaces in truncated octahedral primary particles.

Hongbo Jin, Jiahao Zhang, Li Qin, Yanjie Hu, Hao Jiang, and Chunzhong Li : Dual Modification of Olivine LiFe0.5Mn0.5PO4 Cathodes with Accelerated Kinetics for High-Rate Lithium-Ion Batteries; Ind. Eng. Chem. Res. 2023, 62, 2, 1029–1034 (https://doi.org/10.1021/acs.iecr.2c04303)

Abstract

Developing olivine-type lithium ferromanganese phosphates with high ionic/electronic conductivity is vital to promote their practical application in long-life and high-rate lithium-ion batteries (LIBs). Herein, we propose a dual modification strategy combining C-coating and Nb-doping and apply it to enhance LiFe0.5Mn0.5PO4 cathode materials. The uniform and compact C-coating layer successfully fabricates the high-speed conductive network among primary particles and meantime prevents the attack of electrolytes. The strong Nb–O coordination can effectively accelerate ion diffusion and electron transport within the nanoparticles while suppressing the Jahn–Teller effect of Mn3+. The dual modifications synergistically improve the LiFe0.5Mn0.5PO4 cathode materials with superior lithium-storage capacities of 152 and 115 mAh g–1 at 0.1 and 5 C, respectively. Furthermore, it exhibits an impressive cycling performance with an ultrahigh capacity retention of 95.4% after 1000 cycles at 1 C. These findings extend the application of surface-to-bulk co-modification in developing novel cathode materials used in high-performance LIBs.

Si-Rui Zhao, Zi-Xiang Liu, Jin-Ku Liu, Jichang Liu, Bo Luan, Yun-Sheng Ma, and Peng-Peng Liu: Enhanced Weathering and Corrosion Resistance of Eu-Doped ZnO Solid Solution Material by Fluorescence Modification;  Ind. Eng. Chem. Res. 2023, 62, 2, 1035–1043 (https://doi.org/10.1021/acs.iecr.2c04350)

Abstract

Influencing the electrochemical properties of materials by modulating luminescence is a fascinating topic. It was found that the corrosion protection of the material could be enhanced by fluorescence. Utilizing the fluorescence of the material, the energy of the photons entering the system is reduced, thereby increasing the durability of the coating. The experimental results showed that the europium-doped zinc oxide solid solution (ZEOSS) composite shielding layer has good weathering resistance. The corrosion inhibition efficiency of the ZEOSS composite shielding layer in the laboratory was 751.8% of that of the epoxy resin coating. The corrosion inhibition efficiency in the atmosphere was further improved to 916.0%. The improved corrosion resistance is attributed to the improvement in energy conversion, electron transport hindrance, and shielding properties of the ZEOSS material. Therefore, it is of great importance to explore the enhanced corrosion inhibition of materials through optical modifications.

Khim Hoong Chu, Mohd Ali Hashim, Hadis Bashiri, Jean Debord, Michel Harel, and Jean-Claude Bollinger:  The Flory–Huggins Isotherm and Water Contaminant Adsorption: Debunking Some Modeling Fallacies;  Ind. Eng. Chem. Res. 2023, 62, 2, 1121–1131 (https://doi.org/10.1021/acs.iecr.2c03799)

Abstract

The Flory–Huggins (FH) isotherm first appeared in the literature of water contaminant adsorption in the mid-2000s. It has come into the limelight and received considerable attention in recent years, in large part due to regular coverage in review articles. Here, we point out that a linear form of the FH isotherm is incompatible with the original nonlinear version. We show conclusively that the original FH isotherm was destroyed beyond recognition by the linearization method. As a result, the linearized FH isotherm suffers from the following serious defects: (1) Its parameter estimates are incorrect and nonsensical. (2) It is not possible to plot standard isotherm curves in the form of adsorbed phase concentration versus liquid phase concentration. These anomalies, or “red flags”, that arise in the use of the linearized FH isotherm in data correlation are reported for the first time. To avoid publishing meaningless research, it is advisable to use the original form of the FH isotherm in data fitting. To go beyond routine application (e.g., simple data correlation and thermodynamic calculation), this work describes a novel application that uses the FH isotherm to evaluate the energy distribution of heterogeneous adsorbents.

Chenyang Deng, Zhifei Hu, Mingming Wang, Yanan Wang, Zhigang Wang, Tianjia Chen, Xiaoyao Tan, and Shaomin Liu: Sintering of the Metallic Nickel Hollow Fibers into High-Performance Membranes for H2 Permeation;   Ind. Eng. Chem. Res. 2023, 62, 2, 1132–1140 (https://doi.org/10.1021/acs.iecr.2c04024)

Abstract

The sintering process is a crucial step for fabricating nickel hollow fiber membranes (NHFMs), which significantly affects hydrogen permeability of the membrane and the qualified rate of membrane manufacturing. Optimizing sintering conditions will accelerate the industrial applications of nickel hollow fiber membranes. In this work, the effects of the sintering conditions (temperatures, duration, and the atmosphere) on the membrane microstructure and hydrogen permeation performance of the resultant NHFMs are extensively investigated. Results show that small metal grain size results in large grain boundary density, leading to enhanced hydrogen permeability and decreased activation energy for hydrogen permeation. Sintering temperatures significantly affect the metal grain size, thereby affecting hydrogen permeation and activation energy. When the sintering temperature decreases from 1400 to 1100 °C, the hydrogen flux remarkably increases by a factor of 2 and the activation energy decreases from 57.47 to 48.89 kJ mol–1. On the other hand, increasing the sintering time and hydrogen concentration in the sintering atmosphere only slightly affects the grain size and thus results in a minor change in hydrogen permeation. However, short sintering time and low hydrogen concentration in the sintering atmosphere may cause defects on the membrane and increase the difficulties on full removal of carbon residues in the membrane, which leads to the decrease in the qualified rate of produced membranes.

Zixuan Wang, Dandan Wu, Xi Wang, Ye Huang, and Xu Wu:  Green Phosphate Route of Regeneration of LiFePO4 Composite Materials from Spent Lithium-Ion Batteries; Ind. Eng. Chem. Res. 2023, 62, 2, 1181–1194 (https://doi.org/10.1021/acs.iecr.2c03743)

Abstract

To develop efficient, viable, and promising routes to regenerate nano-LiFePO4 (nano-LFP) composite materials from spent LFP batteries, this paper studied phosphate approaches by taking Li3PO4 and FePO4 as raw materials. The crystalline structure, morphology, and physicochemical properties of regenerated LiFePO4 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurement. Regenerated LiFePO4 owned a good olivine structure with a space group of Pnma. After being coated with carbon, rectangular-structured LiFePO4 prepared by hydrothermal synthesis exhibited high specific capacity, excellent rate capability, and good Li diffusivity. When the pH value was around 8.0 and the amount of the Li+3PO4 raw material was 14 mmol, the discharge capacity at 0.1C was 158.6 mAh g–1 and the capacity retention rate was 99.19% at 1C after 300 cycles. Meanwhile, flake-like LiFePO4/C synthesized by the carbothermal method at 700 °C and a 14 wt % carbon mass fraction showed an initial discharge capacity of 159.0 mAh g–1 at 0.1C and a capacity retention rate of 97.45% after 300 cycles at 1C, exhibiting excellent electrochemical performance. Overall, this study provides a facile, feasible, and sustainable recovery method for the battery industry for recovering phosphate products from spent LFP cathode materials and subsequent large-scale regeneration of LiFePO4 composite materials.

Wai Siong Chai,  Jie Ying Cheun, P.Senthil Kumar, Kuhammad Mubashir, Zahid Majeed, Fawzi  Banat, Shih-Hsin Ho, Pau Loke Show:  A review on conventional and novel materials towards heavy metal adsorption in wastewater treatment application; Journal of Cleaner Production, Volume 296, 10 May 2021, 126589 (https://doi.org/10.1016/j.jclepro.2021.126589)

Abstract

Wastewater treatment remains a critical issue globally till date despite various technological advancements and breakthroughs. Heavy metal in wastewater poses a great threat to human health if untreated properly, which makes its removal of utmost importance. Among various wastewater treatment techniques, adsorption is the most common technique to remove heavy metal in wastewater due to its flexible design, operation, and cost-effectiveness. Activated carbon being the most conventional adsorbent to remove heavy metal ion in wastewater owing to its microporous structure and ease of surface functionalization. However, the activated carbon separation from wastewater solution has been difficult and its high cost have prohibited its wide usage. Recently, the emergence of different novel materials has also showed their competitiveness in heavy metal ion removal. These promising novel materials exhibit several excellent attributes, for example large surface area, great mechanical strength, and high chemical inertness. This paper presents a brief review on the use, theory and future perspectives of conventional, as well as novel materials towards heavy metal adsorption in wastewater treatment application.

Jiayu Feng, Ping Ning, Kai Li, Xin Sun, Chi Wang, Lijuan Jia, and Maohong Fan: One-Step Synthesis of Ammonia Directly from Wet Air/N2 by Plasma Combined with a γ-Al2O3 Catalyst;  ACS Sustainable Chem. Eng. 2023, 11, 2, 804–814 (https://doi.org/10.1021/acssuschemeng.2c06706)

Abstract

The conventional Haber–Bosch NH3 synthesis process requires high temperatures and pressures, resulting in a high carbon footprint and the need to develop alternative NH3 synthesis methods. Accordingly, plasma-based and γ-Al2O3-catalyzed NH3 synthesis from H2O (a hydrogen source) and air/N2 (a nitrogen source) was studied under low temperature and low pressure conditions. The experimental results show that NH3 can be synthesized with air/N2 and H2O, although byproducts such as NO and N2O are also formed. The NH3 formation rate resulting from the use of N2 and H2O is higher than that of air and H2O. Increasing specific energy input (SEI) can increase the NH3 formation rate. Nevertheless, the energy efficiency of NH3 synthesis technology first increases and then decreases with SEI. An NH3 formation rate of 2.92 μmol h–1 g–1 was achieved with an SEI of 11.68 J mL–1 and energy efficiency of 5.10 mg kW–1 h–1 (1.28 mg kWh–1g–1), when wet air at a flow rate of 200 mL min–1 was introduced into the dielectric barrier discharge (DBD) reactor, which was lower than that (4.30 μmol h–1 g–1) attained with N2 + H2O under an SEI of 11.50 J mL–1 and energy efficiency of 7.63 mg kW–1 h–1 (1.91 mg kWh–1g–1). Additionally, the γ-Al2O3 catalyst exhibited good stability. Different results show that plasma-based and γ-Al2O3 catalyzed NH3 synthesis technology is promising.

Jiuyong Li, Weiming Liu, Youxiu Wei, and Yue Yan: SiO2: A Novel Electrolyte for High-Performance All-Solid-State Electrochromic Devices;   ACS Sustainable Chem. Eng. 2023, 11, 2, 824–830 (https://doi.org/10.1021/acssuschemeng.2c06780)

Abstract

For the practical application of electrochromic devices (ECDs), the development and preparation of high-performance electrolyte materials is one of the urgent problems to be solved. In this work, an all-solid-state ECD with the integrated structure of glass/ITO/WO3/Li/SiO2/NiO/ITO has been prepared by the magnetron sputtering method. The amorphous SiO2 film prepared by pulsed direct current reactive magnetron sputtering was used as the electrolyte layer in the ECD for the first time and shows promising potential due to its ultrahigh transparency, good intrinsic electronic insulation, and loose structure for fast ion conduction. The ECD exhibits low leakage current density (8.5 μA cm–2 for bleaching and 43.4 μA cm–2 for coloring), high optical modulation (ΔT = 71.9% at 707 nm), fast response speed (1.1 s for the bleaching process and 8.5 s for the coloring process), excellent cycle stability, and high coloration efficiency (126.4 cm2 C–1). This work not only indicates that SiO2 as a dielectric material can be used as the electrolyte layer in all-solid-state ECDs but also provides new avenues in the selection of electrolyte materials for the preparation of high-performance ECDs.

Choi, W., Ha, J., Kim, Y. T., & Choi, J. (2022): Highly Stable Iron-and Carbon-Based Electrodes for Li-Ion Batteries: Negative Fading and Fast Charging within 12 Min. ChemSusChem, 15(19), e202201137. https://doi/10.1002/cssc.202201137

Abstract

Lithium-ion batteries (LIBs) with high energy density and safety under fast-charging conditions are highly desirable for electric vehicles. However, owing to the growth of Li dendrites, increased temperature at high charging rates, and low specific capacity in commercially available anodes, they cannot meet the market demand. In this study, a facile one-pot electrochemical self-assembly approach has been developed for constructing hybrid electrodes composed of ultrafine Fe3O4 particles on reduced graphene oxide (Fe3O4@rGO) as anodes for LIBs. The rationally designed Fe3O4@rGO electrode containing 36 wt % rGO exhibits an increase in specific capacity as cycling progresses, owing to improvements in the active sites, electrochemical kinetics, and catalytic behavior, leading to a high specific capacity of 833 mAh g−1 and outstanding cycling stability over 2000 cycles with a capacity loss of only 0.127 % per cycle at 5 A g−1, enabling the full charging of batteries within 12 min. Furthermore, the origin of this abnormal improvement in the specific capacity (called negative fading), which exceeds the theoretical capacity, is investigated. This study opens up new possibilities for the commercial feasibility of Fe3O4@rGO anodes in fast-charging LIBs.

Zhang, S., Zeng, Z., Zhai, W., Hou, G., Chen, L., & Ci, L. (2021): Bifunctional in situ polymerized interface for stable LAGP-based lithium metal batteries. Advanced Materials Interfaces, 8(10), 2100072. https://doi.org/10.1002/admi.202100072

Abstract

All-solid-state lithium metal batteries (ASSLMBs) have attracted intensive research attention since their incomparable energy density and the further advance of ASSLMBs is severely dependent on the development of solid electrolytes. Unfortunately, as one of the most studied solid electrolytes, the practical applications of (NASICON)-type Li1.5Al0.5Ge0.5P3O12 (LAGP) electrolyte is hindered by not only its inferior interfacial contact with electrodes but also its undesirable instability toward Li metal anodes. In this work, a bifunctional in situ formed poly(vinylene carbonate) (PVCA)-based buffer layer is introduced between the LAGP electrolyte and the metallic Li anode to improve interface compatibility and the electrolyte stability. The improved interface contact between LAGP and electrodes and the enhanced stability of LAGP enable ASSLMBs with excellent electrochemical performance. The Li/LAGP/Li symmetric cell with the PVCA-based interlayer can maintain a low overpotential of 80 mV for 800 h at 0.05 mA cm–2. Inspiringly, the as-assembled ASSLMBs with LiFePO4 as the cathode also present excellent cyclic stability with a high initial discharge capacity of 150 mAh g–1 at 0.5 C and superior capacity retention of 96% after 200 cycles.

Chen, Y., Huo, F., Chen, S., Cai, W., & Zhang, S. (2021): In-built quasi-solid-state poly-ether electrolytes enabling stable cycling of high-voltage and wide-temperature Li metal batteries. Advanced Functional Materials, 31(36), 2102347. https://doi.org/10.1002/adfm.202102347

Abstract

Developing solid-state electrolytes with good compatibility for high-voltage cathodes and reliable operation of batteries over a wide-temperature-range are two bottleneck requirements for practical applications of solid-state metal batteries (SSMBs). Here, an in situ quasi solid-state poly-ether electrolyte (SPEE) with a nano-hierarchical design is reported. A solid-eutectic electrolyte is employed on the cathode surface to achieve highly-stable performance in thermodynamic and electrochemical aspects. This performance is mainly due to an improved compatibility in the electrode/electrolyte interface by nano-hierarchical SPEE and a reinforced interface stability, resulting in superb-cyclic stability in Li||Li symmetric batteries (>4000 h at 1 mA cm−2/1 mAh cm−2; >2000 h at 1 mA cm−2/4 mAh cm−2), which are the same for Na, K, and Zn batteries. The SPEE enables outstanding cycle-stability for wide-temperature operation (15–100 °C) and 4 V-above batteries (Li||LiCoO2 and Li||LiNi0.8Co0.1Mn0.1O2). The work paves the way for development of practical SSMBs that meet the demands for wide-temperature applicability, high-energy density, long lifespan, and mass production.

Zhang, L., Wang, Z., Zhou, H., Li, X., Liu, Q., Wang, P., & Yuan, A. (2022): Synergistic Coupling of Li6. 4La3Zr1. 4Ta0. 6O12 and Fluoroethylene Carbonate Boosts Electrochemical Performances of Poly (Ethylene Oxide)- Based All-Solid-State Lithium Batteries. ChemElectroChem, 9(17), e202200641. https://doi/10.1002/celc.202200641

Abstract

All-solid-state lithium batteries (ASSLBs) with poly(ethylene oxide) (PEO)-based composites solid-state electrolytes have received much attention owing to their higher energy density and better safety compared with conventional liquid electrolytes. However, ASSLBs with PEO-based solid-state electrolytes generally suffer from severe capacity degradation and interface transfer obstacles during the charge/discharge process. In this work, fluoroethylene carbonate (FEC) is employed as a reducing additive to in-situ form LiF-rich and stable solid-state electrolyte interface (SEI). Benefiting from the integrated advantages of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) and FEC binary additives, the number of lithium-ion transference increases to 0.48, which facilitates the stable cycling of Li||Li symmetrical batteries over 900 h at 0.1 mA cm−2. The synergistic interplay of LLZTO and FEC constructs a stable LiF-rich SEI film, effectively addressing the interfacial problems caused by lithium dendrites and promoting the transport of Li ions. Therefore, the high ionic conductivity and self-healing anode-electrolyte interface are achieved. This study provides a facile and economical strategy to solve the problem of the lithium-electrolyte interface. It is of great scientific significance for the development of dendrite-free solid-state lithium metal batteries.

Cai, S., Chu, X., Liu, C., Lai, H., Chen, H., Jiang, Y., … & Gao, C. (2021): Water–Salt Oligomers Enable Supersoluble Electrolytes for High-Performance Aqueous Batteries. Advanced Materials, 33(13), 2007470. https://doi.org/10.1002/adma.202007470

Abstract

Aqueous rechargeable batteries are highly safe, low-cost, and environmentally friendly, but restricted by low energy density. One of the most efficient solutions is to improve the concentration of the aqueous electrolytes. However, each salt is limited by its physical solubility, generally below 21–32 mol kg−1 (m). Here, a ZnCl2/ZnBr2/Zn(OAc)2 aqueous electrolyte with a record super-solubility up to 75 m is reported, which breaks through the physical solubility limit. This is attributed to the formation of acetate-capped water–salt oligomers bridged by Br−/Cl−-H and Br−/Cl−/O-Zn2+ interactions. Mass spectrometry indicates that acetate anions containing nonpolarized protons prohibit the overgrowth and precipitation of ionic oligomers. The polymer-like glass transition temperature of such inorganic electrolytes is found at ≈−70 to −60 °C, without the observation of peaks for salt-crystallization and water-freezing from 40 to −80 °C. This supersoluble electrolyte enables high-performance aqueous dual-ion batteries that exhibit a reversible capacity of 605.7 mAh g−1, corresponding to an energy density of 908.5 Wh kg−1, with a coulombic efficiency of 98.07%. In situ X-ray diffraction and Raman technologies reveal that such high ionic concentrations of the supersoluble electrolyte enable a stage-1 intercalation of bromine into macroscopically assembled graphene cathode.

Jeena, C. B., Elsa, P. J., Moly, P. P., Ambily, K. J., & Joy, V. T. (2022): A dendrite free Zn-Fe hybrid redox flow battery for renewable energy storage. Energy Storage, 4(1), e275. https://doi.org/10.1002/est2.275

Abstract

About two thirds of global greenhouse emissions is caused by burning of fossil fuels for energy purposes and this has spurred great research interest to develop renewable energy technologies based on wind, solar power, and so on. Redox flow batteries (RFB) are receiving wide attention as scalable energy-storage systems to address the intermittency issues of renewable energy sources. However, for widespread commercialization, the redox flow batteries should be economically viable and environmentally friendly. Zinc based batteries are good choice for energy storage devices because zinc is earth abundant and zinc metal has a moderate specific capacity of 820 mA hg−1 and high volumetric capacity of 5851 mA h cm−3. We herein report a zinc-iron (Zn-Fe) hybrid RFB employing Zn/Zn(II) and Fe(II)/Fe(III) redox couples as positive and negative redox systems, respectively, separated by a self-made anion exchange membrane (AEM). The battery delivers a good discharge voltage of approximately 1.34 V at 25 mA cm−2, with a coulombic efficiency (CE) of 92%, voltage efficiency (VE) of 85% and energy efficiency (EE) of ~78% for 30 charge-discharge cycles. Repeated galvanostatic charge/discharge cycles show no degradation in performance, confirming the excellent stability of the system. A key advancement in the present Zn-Fe hybrid redox flow battery with AEM separator is that no dendrite growth was observed on zinc electrode on repeated charge-discharge cycles, which was the serious drawback of many previously reported zinc based redox flow batteries.

Ashraf, M., Shah, S. S., Khan, I., Aziz, M. A., Ullah, N., Khan, M., … & Tahir, M. N. (2021): A High-Performance Asymmetric Supercapacitor Based on Tungsten Oxide Nanoplates and Highly Reduced Graphene Oxide Electrodes. Chemistry–A European Journal, 27(23), 6973-6984.               https://doi/10.1002/chem.202005156

Abstract

Tungsten oxide/graphene hybrid materials are attractive semiconductors for energy-related applications. Herein, we report an asymmetric supercapacitor (ASC, HRG//m-WO3 ASC), fabricated from monoclinic tungsten oxide (m-WO3) nanoplates as a negative electrode and highly reduced graphene oxide (HRG) as a positive electrode material. The supercapacitor performance of the prepared electrodes was evaluated in an aqueous electrolyte (1 M H2SO4) using three- and two-electrode systems. The HRG//m-WO3 ASC exhibits a maximum specific capacitance of 389 F g−1 at a current density of 0.5 A g−1, with an associated high energy density of 93 Wh kg−1 at a power density of 500 W kg−1 in a wide 1.6 V operating potential window. In addition, the HRG//m-WO3 ASC displays long-term cycling stability, maintaining 92 % of the original specific capacitance after 5000 galvanostatic charge–discharge cycles. The m-WO3 nanoplates were prepared hydrothermally while HRG was synthesized by a modified Hummers method.