Nano-Confined Tin Oxide in Carbon Nanotube Electrodes via Electrostatic Spray Deposition for Lithium-Ion Batteries:  Alexandra Henriques, Amin Rabiei Baboukani, Borzooye Jafarizadeh, Azmal Huda Chowdhury  and Chunlei Wang; Materials 2022, 15(24), 9086 (https://doi.org/10.3390/ma15249086)

Abstract

The development of novel materials is essential for the next generation of electric vehicles and portable devices. Tin oxide (SnO2), with its relatively high theoretical capacity, has been considered as a promising anode material for applications in energy storage devices. However, the SnO2 anode material suffers from poor conductivity and huge volume expansion during charge/discharge cycles. In this study, we evaluated an approach to control the conductivity and volume change of SnO2 through a controllable and effective method by confining different percentages of SnO2 nanoparticles into carbon nanotubes (CNTs). The binder-free confined SnO2 in CNT composite was deposited via an electrostatic spray deposition technique. The morphology of the synthesized and deposited composite was evaluated by scanning electron microscopy and high-resolution transmission electron spectroscopy. The binder-free 20% confined SnO2 in CNT anode delivered a high reversible capacity of 770.6 mAh g−1. The specific capacity of the anode increased to 1069.7 mAh g−1 after 200 cycles, owing to the electrochemical milling effect. The delivered specific capacity after 200 cycles shows that developed novel anode material is suitable for lithium-ion batteries (LIBs).

Correlation between Laboratory-Accelerated Corrosion and Field Exposure Test for High-Strength Stainless Steels:  Jinchao Jiao, Yong Lian, Zhao Liu, He Guo, Jin Zhang, Yan Su, Junpeng Teng, Yiming Jin and Jinyan Chen;  Materials 2022, 15(24), 9075; https://doi.org/10.3390/ma15249075

Abstract

Equipment in a long-term marine atmosphere environment is prone to corrosion failure. Natural field exposure tests usually require a long time to obtain corrosion information. This study worked out a laboratory-accelerated corrosion test method that has a strong correlation with the natural environment test in Wanning, Hainan, and can be used as the basis for life assessment and the prediction of two high-strength stainless-steel materials. The mathematical model of corrosion weight loss of two high-strength stainless steels (3Cr13 and 00Cr12Ni10MoTi) was established by a field exposure test and a laboratory-accelerated corrosion test. Then, the correlation between the field exposure test and the laboratory-accelerated corrosion test was evaluated using qualitative and quantitative methods, and the acceleration ratio was calculated using the accelerated switching factor (ASF) method. The results show that: (1) The corrosion morphology of the two stainless steels after 15 days of laboratory-accelerated corrosion testing is similar to that obtained after two years of field exposure. (2) The value of gray correlation between the laboratory-accelerated corrosion test and the field exposure test is not less than 0.75. (3) The acceleration ratio of both stainless steels increases with the corrosion test time in the laboratory. The corrosion prediction models for the two stainless steels are T3Cr13 = 6.234 t1.634 and T00Cr12Ni10MoTi = 55.693 t1.322, respectively.

Direct Synthesis of Ethylene and Hydrogen from CO2 and Ethane over a Bifunctional Structured CaO/Cr2O3-V2O5/ZSM-5 Adsorbent/Catalyst Monolith: Khaled Baamran, Ali A.Rownaghi, and Fateme Rezaei;  ACS Sustainable Chem. Eng. 2023, 11, 3, 1006–1018 (https://doi.org/10.1021/acssuschemeng.2c05627)

Abstract

In this study, we synthesized bifunctional adsorbent/catalyst materials (BFMs) consisting of a CaO adsorbent admixed with Cr2O3-V2O5/ZSM-5 catalysts. The obtained BFMs were further formulated, processed, and shaped through additive manufacturing (3D printing) method. The physical and chemical properties of structured CaO/Cr2O3-V2O5/ZSM-5 adsorbent/catalyst monoliths were thoroughly characterized and evaluated. The effects of operating conditions including reaction temperature, ethane composition, and space velocity on single-bed CO2 capture and selective formation of ethylene and hydrogen were systematically investigated. The adsorption–reaction experiments revealed that Cr-based BFMs, in particular, CaO/Cr4/ZSM-5 monoliths undergo the oxidative dehydrogenation pathway with high C2H4 selectivity, whereas increasing the content of V leads to enhanced catalytic activity for the reforming pathway to produce hydrogen. The best adsorption/catalyst BFM performance was observed for CaO/Cr1-V3/ZSM-5, which was balanced between the two reaction pathways and resulted in 1.72 mmol/g CO2 capture capacity, 63.95% CO2 conversion, 22.4% C2H6 conversion, 42% C2H4 selectivity, and 45% syngas (31% hydrogen) selectivity. Furthermore, the cyclic test results revealed excellent catalytic stability across the initial two cycles over CaO/Cr1-V3/ZSM-5 monolith, highlighting the synergetic effect of bimetallic catalyst constituents on maintaining high catalytic durability. This novel formulation and processing method can pave the way toward formulation of various structured BFM monoliths with cooperative CO2 adsorptive removal and catalytic performance for one-pot CO2 capture–utilization and simultaneous production of light olefins and hydrogen.

Navigating within the Safe Operating Space with Carbon Capture On-Board: Valentina Negri, Margarita A. Charalambous, Juan D. Medrano-García, and Gonzalo Guillén-Gosálbez; ACS Sustainable Chem. Eng. 2022, 10, 51, 17134–17142 (https://doi.org/10.1021/acssuschemeng.2c04627)

Abstract

Despite the global pandemic that recently affected human and cargo transportation, the emissions of the maritime sector are projected to keep growing steadily. The International Maritime Organization focused on boosting the fleets’ efficiency to improve their environmental performance, while more sustainable fuels are currently under investigation. Here, we assess the economic, technical, and environmental feasibility of an interim solution for low-carbon shipping using state-of-the-art CO2 capture technology, namely, chemical absorption, on-board cargo ships. We compute the carbon footprint of this alternative and perform an absolute sustainability study based on seven planetary boundaries. Our results show that the capture on-board scenario can achieve 94% efficiency on the net CO2 emissions at 85 $/tCO2 while substantially reducing impacts on core planetary boundaries (relative to the business as usual) and outperforming a direct air capture scenario in global warming and all planetary boundaries, except for the nitrogen flow. Hence, capture on-board seems an appealing solution to decarbonize shipping in the short term while alternative carbon-free fuels and related infrastructure are developed and deployed.

Synthesis of a Low-Cost V3.5+ Electrolyte for Vanadium Redox Flow Batteries through the Catalytic Reduction of V2O5: Hansol Choi, Debasish Mandal, and Hansung Kim;  ACS Sustainable Chem. Eng. 2022, 10, 51, 17143–17150 (https://doi.org/10.1021/acssuschemeng.2c04632)

Abstract

In this study, a cost-effective method for preparing a V3.5+ electrolyte for a vanadium redox flow battery (VRFB) was developed using the cheapest vanadium precursor, V2O5, through the catalytic reduction method. It is revealed that VRFBs do not operate properly with a V3.5+ electrolyte prepared by the catalytic reduction method using V2O5 salts because of the significant H ion consumption during the catalytic reduction reaction, contributing to a decrease in the solution’s viscosity. As a result, more vanadium ions could permeate through the membrane, increasing the imbalance between the negative and positive electrolytes. To solve this problem, the H ions corresponding to the amount consumed during the catalytic reduction reaction were replenished using a H ion-supplemented electrolyte. This electrolyte exhibited an excellent VRFB performance, comparable to that of standard V+++3.5+ electrolytes prepared by the expensive and time-consuming electrolysis of VOSO4 salts. Thus, this study offers a simple strategy for the cost-efficient production of the V3.5+ electrolyte.

Light-Induced Defect Formation and Pt Single Atoms Synergistically Boost Photocatalytic H2 Production in 2D TiO2-Bronze Nanosheets: Sourav Rej, S. M. Hossein Hejazi, Zdeněk Badura, Giorgio Zoppellaro, Sergii Kalytchuk, Štěpán Kment, Paolo Fornasiero, and Alberto Naldoni;  ACS Sustainable Chem. Eng. 2022, 10, 51, 17286–17296 (https://doi.org/10.1021/acssuschemeng.2c05708)

Abstract

Ultrathin two-dimensional (2D) semiconductor nanosheets decorated with single atomic species (SAs) have recently attracted increasing attention due to their abundant surface-exposed reactive sites and maximum SAs binding capabilities thus lowering the catalyst cost, without sacrificing high performance for photocatalytic hydrogen (H2) production from water. Here, we present a strategy to prepare titanium dioxide-bronze nanosheets (TiO2-BNS) and H2-reduced TiO2 nanosheets (TiO2-HRNS) synthesized, characterized, and applied for photocatalytic H2 production. Surprisingly, black TiO2-HRNS show complete photo inactivity, while the TiO2-BNS-Pt0.05 nanohybrid shows excellent H2 production rate with a very low loading of 0.05 wt % Pt. TiO2-BNS-Pt0.05 presents around 10 and 99 times higher photocatalytic rate than pristine TiO2-BNS under solar and 365 nm UV-LED light irradiation, respectively. Due to the 2D morphology and the presence of abundant coordinating sites, the successful formation of widely dispersed Pt SAs was achieved. Most excitingly, the in situ formation of surface-exposed defect sites (Ti3+) was observed for TiO2-BNS under light illumination, suggesting their significant role in enhancing the H2 production rate. This self-activation and amplification behavior of TiO2-BNS can be extended to other 2D systems and applied to other photocatalytic reactions, thus providing a facile approach for fully utilizing noble metal catalysts via the successful formation of SAs.

Breaking the N2 Solubility Limit to Achieve Efficient Electrosynthesis of NH3 over Cr-Based Spinel Oxides:  Baochen Cui, Yanming Lei, Zhucheng Li, Yancheng Wang, and Shuzhi Liu;  ACS Sustainable Chem. Eng. 2022, 10, 51, 17297–17307 (https://doi.org/10.1021/acssuschemeng.2c05731)

Abstract

Electrochemical synthesis of NH3 from H2O and N2, as a sustainable alternative to the Haber–Bosch process, has attracted extensive attention. However, the achievement of effective NH3 electrosynthesis remains challenging since N2 features remarkable thermodynamic stability and ultralow solubility in aqueous electrolytes. Here, we prepare new-type Cr-based spinel oxides using co-precipitation and hydrothermal methods. The ternary spinel ZnCr2–xFexO4 phases are formed by substituting Fe3+ ions for Cr3+ ions at octahedral sites of ZnCr2O4. The introduction of Fe results in lattice expansion, lattice distortion, an increase in oxygen vacancies, and a remarkable change in the electronic structure, which further affect nitrogen chemisorption and activation properties. The as-fabricated ZnCr1.2Fe0.8O4 spinel has bifunctional active sites of Cr3+ and Fe3+ and exhibits large capacity and moderate strength of N2 chemisorption. To break the N2 solubility limit in the aqueous electrolytes for electrosynthesis of NH3, a novel two-step process of gas-phase N2 adsorption and electroreduction is successfully developed. The catalyst has excellent catalytic performances with an ammonia formation rate of 29.26 μg h–1 cm–2, the highest Faradaic efficiency of 18.41%, and long-term stability for 20 h. This study provides a new strategy for developing a highly efficient electrocatalyst for the electrosynthesis of NH3.

Effect of the Partial Replacement of Cement with Waste Granite Powder on the Properties of Fresh and Hardened Mortars for Masonry Applications:  Zuzanna Zofia Woźniak, Adrian Chajec  and Łukasz Sadowski; Materials 2022, 15(24), 9066; https://doi.org/10.3390/ma15249066

Abstract

Granite is a well-known building and decorative material, and, therefore, the amount of produced waste in the form of granite powder is a problem. Granite powder affects the health of people living near landfills. Dust particles floating in the air, which are blown by gusts of wind, can lead to lung silicosis and eye infections, and can also affect the immune system. To find an application for this kind of waste material, it was decided to study the effect of partially replacing cement with waste granite powder on the properties of fresh and hardened mortars intended for masonry applications. The authors planned to replace 5%, 10%, and 15% of cement with waste material. Series of mortar with the addition of granite powder achieved 50% to 70% of the compressive strength of the reference series, and 60% to 76% of the bending strength of the reference series. The partial replacement of cement with the granite powder significantly increased the water sorption coefficient. The consistency of the fresh mortar, and its density and water absorption also increased when compared to the reference series. Therefore, Granite powder can be used as a partial replacement of cement in masonry mortars.

Investigation of the Effect of ECAP Parameters on Hardness, Tensile Properties, Impact Toughness, and Electrical Conductivity of Pure Cu through Machine Learning Predictive Models:  Mahmoud Shaban, Mohammed F. Alsharekh,Fahad Nasser Alsunaydih,Abdulrahman I. Alateyah,Majed O. Alawad,Amal BaQais,Mokhtar Kamel,Ahmed Nassef,Medhat A. El-Hadek  and  Waleed H. El-Garaihy; Materials 2022, 15(24), 9032; https://doi.org/10.3390/ma15249032

Abstract

Copper and its related alloys are frequently adopted in contemporary industry due to their outstanding properties, which include mechanical, electrical, and electronic applications. Equal channel angular pressing (ECAP) is a novel method for producing ultrafine-grained or nanomaterials. Modeling material design processes provides exceptionally efficient techniques for minimizing the efforts and time spent on experimental work to manufacture Cu or its associated alloys through the ECAP process. Although there have been various physical-based models, they are frequently coupled with several restrictions and still require significant time and effort to calibrate and enhance their accuracies. Machine learning (ML) techniques that rely primarily on data-driven models are a viable alternative modeling approach that has recently achieved breakthrough achievements. Several ML algorithms were used in the modeling training and testing phases of this work to imitate the influence of ECAP processing parameters on the mechanical and electrical characteristics of pure Cu, including the number of passes (N), ECAP die angle (φ), processing temperature, and route type. Several experiments were conducted on pure commercial Cu while altering the ECAP processing parameters settings. Linear regression, regression trees, ensembles of regression trees, the Gaussian process, support vector regression, and artificial neural networks are the ML algorithms used in this study. Model predictive performance was assessed using metrics such as root-mean-squared errors and R2 scores. The methodologies presented here demonstrated that they could be effectively used to reduce experimental effort and time by reducing the number of experiments runs required to optimize the material attributes aimed at modeling the ECAP conditions for the following performance characteristics: impact toughness (IT), electrical conductivity (EC), hardness, and tensile characteristics of yield strength (σy), ultimate tensile strength (σu), and ductility (Du)

Catalytic Activity and Coke Resistance of Gasification Slag-Supported Ni Catalysts during Steam Reforming of Plastic Pyrolysis Gas: Hang Meng Ong, Andrei Veksha, Quan Luu Manh Ha, Jijiang Huang, Zviad Tsakadze, and Grzegorz Lisak; ACS Sustainable Chem. Eng. 2022, 10, 51, 17167–17176 (https://doi.org/10.1021/acssuschemeng.2c04946)

Abstract

Pyrolysis gas from polyolefinic plastic waste is a hydrocarbon-rich feedstock for sustainable syngas production. The effect of Cr, Mo, and W promoters on the activity of gasification slag-supported Ni catalysts during the reforming of plastic pyrolysis gas was investigated (polyethylene and polypropylene mixed feedstock, Ni:promoter molar ratio = 4.5, 800 °C, steam-to-carbon molar ratio of 7). Based on 3 h reforming tests, all catalysts showed stable conversion efficiency, suggesting that gasification slag from municipal solid waste is a promising replacement material for traditionally used alumina supports. Moreover, the slag demonstrated good thermal stability and potential for catalyst recycling, justifying the economic benefit of valorizing the material. Interestingly, interaction between slags and promoters is evidenced by the formation of CaWO4 and CaMoO4 phases, which may have an impact on the reforming activity of bimetallic catalysts. Among the studied catalysts, the highest conversion efficiency of hydrocarbon compounds (76%), highest H2 (122.65 mmol Lfeed–1) and CO (49.34 mmol Lfeed–1) yields, and lowest coke deposition (0.06 wt %) were demonstrated by the Ni–Mo catalyst. The superior performance of Ni–Mo was accompanied by the growth of carbon nanotubes via a tip-growth mechanism, which was not observed in other catalysts. Spherical carbon nanocages and filamentous carbon nanofibers predominated in coke deposits of Ni, Ni–W, and Ni–Cr. The high syngas production efficiency of Ni–Mo could be attributed to the dispersion of metal by the growing carbon nanotubes providing the reaction sites for reforming and coke gasification reactions. Owing to these properties, Ni catalyst promoted by Mo and loaded on a gasification support has high potential for the syngas production from plastic pyrolysis gas.

Examining Electrolyte Compatibility on Polymorphic MnO2 Cathodes for Room-Temperature Rechargeable Magnesium Batteries: Xiatong Ye, Hongyi Li, Takuya Hatakeyama, Hiroaki Kobayashi, Toshihiko Mandai, Norihiko L. Okamoto, and Tetsu Ichitsubo;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56685–56696 (https://doi.org/10.1021/acsami.2c14193)

Abstract

Rechargeable magnesium batteries are promising candidates for post-lithium-ion batteries, owing to the large source abundance and high theoretical energy density. However, there remain few reports on constructing practical cells with oxide cathodes and Mg anodes at room temperature. In this work, we compare the reaction behavior of various MnO2 polymorph cathodes in two representative electrolytes: Mg[TFSA]2/G3 and Mg[Al(hfip)4]2/G3. In Mg[TFSA]2/G3, discharge capacities of the MnO2 cathodes are well consistent with the changes in Mg composition, where nanorod-like α-MnO2 and λ-MnO2 show the capacities of about 100 mA h g–1 at room temperature. However, this electrolyte has the disadvantage that the Mg anodes are easily passivated. In contrast, Mg[Al(hfip)4]2/G3 allows highly reversible deposition/dissolution of Mg anodes, whereas the discharge process of the MnO2 cathodes involves a large part of side reactions, in which the MnO2 active material takes part in some reductive reaction together with electrolyte species instead of the expected Mg2+ intercalation. Such an unstable electrode/electrolyte interface would lead to continuous degradation on/near the cathode surface. Thus, the interfacial stability between the oxide cathodes and the electrolytes must be improved for practical applications.

Ultralight Porous Cu Nanowire Aerogels as Stable Hosts for High Li-Content Metal Anodes: Sijia Li, Jianyu Chen, Guanyu Liu, Hanbo Wu, Huanran Chen, Mingshi Li, Li Shi, Yizhou Wang, Yanwen Ma, and Jin Zhao;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56697–56706 (https://doi.org/10.1021/acsami.2c14637)

Abstract

Using porous copper (Cu) as the host is one of the most effective approaches to stabilize Li metal anodes. However, the most widely used porous Cu hosts usually account for the excessive mass proportion of composite anodes, which seriously decreases the energy density of Li metal batteries. Herein, an ultralight porous Cu nanowire aerogel (UP-Cu) is reported as the Li metal anode host to accommodate a high mass loading of Li content of 77 wt %. Specifically, the Li/UP-Cu electrode displays a satisfactory gravimetric capacity of 2715 mAh g–1, which is higher than that of the most reported Li metal composite anodes. The UP-Cu host achieves a high Coulombic efficiency of ∼98.9% after 250 cycles in the half cell and exceptional electrochemical stability under high-current-density and deep-plating-stripping conditions in the symmetrical cell. The Li/UP-Cu|LiFePO4 battery displays a specific capacity of 102 mAh g–1 at 5 C for 5000 cycles. The Li/UP-Cu|LiFePO4 pouch cell achieves a significantly high capacity of 146.3 mAh g–1 with a high capacity retention of 95.83% for 360 cycles. This work provides a lightweight porous host to stabilize Li-metal anodes and maintain their high mass-specific capacity.

Lithium-Ion Transport through Complex Interphases in Lithium Metal Batteries: Stefany Angarita-omez and Perla B. Balbuena;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56758–56766 (https://doi.org/10.1021/acsami.2c16598)

Abstract

Lithium metal is one of the best anode candidates for next-generation batteries. However, there are still many unknowns regarding the structure and properties of the solid electrolyte interphase (SEI) formed due to electron transfer reactions between the Li metal surface and the electrolyte. In addition, because of the difficulties to study amorphous and dynamic phases and interphases, there are many questions about the ion diffusion mechanism through complex multicomponent materials and interphases. In this study, using first-principles theory and computation, we focus on developing a better understanding of the ion motion mechanisms in the vicinity of a SEI formed when a seed Li2O or LiOH cluster nucleates on the Li metal surface. We study the role of charge transfer at the interface between charged surfaces and the electrolyte, and we investigate the evolution of inhomogeneous Li metal deposits present in the neighborhood of the SEI nuclei, aiming to fundamentally understand how these events modify the ion transport through complex electrochemically active materials.

Surface Capping Layer Prepared from the Bulky Tetradodecylammonium Bromide as an Efficient Perovskite Passivation Layer for High-Performance Perovskite Solar Cells: Seid Yimer Abate, Surabhi Jha, Guorong Ma, Jawnaye Nash, Nihar Pradhan, Xiaodan Gu, Derek Patton, and Qilin Dai; ACS Appl. Mater. Interfaces 2022, 14, 51, 56900–56909 (https://doi.org/10.1021/acsami.2c19201)

Abstract

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased and levels with silicon solar cells; however, their commercialization has not yet been realized because of their poor long-term stability. One of the primary causes of the instability of PSC devices is the large concentration of defects in the polycrystalline perovskite film. Such defects limit the device performance besides triggering hysteresis and device instability. In this study, tetradodecylammonium bromide (TDDAB) was used as a postsurface modifier to suppress the density of defects from the mixed perovskite film (CsFAMA). X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses validated that TDDAB binds to the mixed perovskite through hydrogen bonding. The X-ray diffraction (XRD) and two-dimensional grazing incidence wide-angle X-ray scattering (2D GIWAXS) study uncovered that the TDDAB modification formed a capping layer of (TDDA)2PbI1.66Br2.34 on the surface of the three-dimensional (3D) perovskite. The single charge transport device prepared from the TDDAB-modified perovskite film revealed that both the electron and hole defects were considerably repressed due to the modification. Consequently, the modified device displayed a champion PCE of 21.33%. The TDDAB surface treatment not only enhances the PCE but the bulky cation of the TDDAB also forms a hydrophobic capping surface (water contact angle of 93.39°) and safeguards the underlayer perovskite from moisture. As a result, the modified PSC has exhibited almost no performance loss after 30 days in air (RH ≈ 40%).

Robust Direct Hydrocarbon Solid Oxide Fuel Cells with Exsolved Anode Nanocatalysts: Tengpeng Wang, Runze Wang, Xiaoyu Xie, Shuo Chang, Tao Wei, Dehua Dong, and Zhi Wang;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56735–56742 (https://doi.org/10.1021/acsami.2c16284)

Abstract

Perovskite anodes with in situ exsolved nanocatalysts have been proven to overcome carbon deposition and increase anode catalytic activity as an alternative to conventional Ni/YSZ anodes for direct hydrocarbon solid oxide fuel cells (SOFCs). This study, for the first time, demonstrates the state-of-the-art exsolution over cathode-supported SOFCs, which achieve the highest cell performance compared to conventional electrolyte-supported SOFCs with perovskite anodes using CH4 as a fuel. The dendritic channel structure of cathode supports retains a high active surface during high-temperature electrolyte sintering. Sr2Ti0.8Co0.2FeO6−δ perovskite ceramic is employed as anodes, and Co–Fe alloy nanoparticles are exsolved after reduction, which increases the cell power output by about 40%. The peak power densities of the cells are 0.82, 0.59, 0.43, and 0.33 W cm–2 at 800 °C using hydrogen, methane, methanol, and ethanol, respectively. The SOFCs with the exsolved nanocatalysts demonstrate stable power generation up to 110 h using methane, methanol, and ethanol fuels. Interestingly, the perovskite anodes show high methane fuel utilization by the complete oxidation of methane, which is in contrast to the partial oxidation over Ni catalysts. Robust hydrocarbon SOFCs have been developed by coupling anode catalyst exsolution with dendritically channeled cathode supports.

Dimensionally Stable Composite Li Electrode with Cu Skeleton and Lithophilic Li–Mg Alloy Microstructure: Xue Liu, Jian Liu, Guo-Ran Li, Sheng Liu, and Xue-Ping Gao;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56801–56807 (https://doi.org/10.1021/acsami.2c17084)

Abstract

Lithium electrodes have gained increasing attention in recent years for their promising applications in high-energy-density secondary batteries. However, structural instability during cycling remains a considerable obstacle to development. In this study, a dimensionally stable Li–Mg/Cu composite electrode was fabricated. Cu foam as a plate grid can sustain the structure, and Li–Mg alloy as the active and lithophilic component can guide the uniform Li plating within the composite. Thus, Li–Mg/Cu electrode shows long-term stability in terms of dimensional change and surface morphology. This work provides a facile and practical way to fabricate composite Li electrodes with high dimensional stability for secondary batteries.

Facile Synthesis of a LiC15H7O4/Graphene Nanocomposite as a High-Property Organic Cathode for Lithium-Ion Batteries: Xiaoyun Yang, Huan Deng, Junfeng Liang, Jiaying Liang, Ronghua Zeng, Ruirui Zhao, Qing Chen, Mingzhe Chen, Yifan Luo, and Shulei Chou;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56808–56816 (https://doi.org/10.1021/acsami.2c17104)

Abstract

Organic electrode materials face two outstanding issues in the practical applications in lithium-ion batteries (LIBs), dissolution and poor electronic conductivity. Herein, we fabricate a nanocomposite of an anthraquinone carboxylate lithium salt (LiAQC) and graphene to address the two issues. LiAQC is synthesized via a green and facile one-pot reaction and then ball-milled with graphene to obtain a nanocomposite (nr-LiAQC/G). For comparison, single LiAQC is also ball-milled to form a nanorod (nr-LiAQC). Together with pristine LiAQC, the three samples are used as cathodes for LIBs. Results show that good cycling performance can be obtained by introducing the −CO2Li hydrophilic group on anthraquinone. Furthermore, the nr-LiAQC/G demonstrates not only a high initial discharge capacity of 187 mAh g–1 at 0.1 C but also good cycling stability (reversible capacity: ∼165 mAh g–1 at 0.1 C after 200 cycles) and good rate capability (the average discharge capacity of 149 mAh g–1 at 2 C). The superior electrochemical properties of the nr-LiAQC/G profit from graphene with high electronic conductivity, the nanorod structure of LiAQC shortening the transport distance for lithium ions and electrons, and the introduction of the −CO2Li hydrophilic group decreasing the dissolution of LiAQC in the electrolyte. Meanwhile, density functional theory calculations support the roles of graphene and −CO2Li groups. The fabrication is general and facile, ready to be extended to other organic electrode materials.

Aging-Responsive Phase Transition of VOOH to V10O24·nH2O vs Zn2+ Storage Performance as a Rechargeable Aqueous Zn-Ion Battery Cathode: Radha Nagraj, Rangaswamy Puttaswamy, Prahlad Yadav, Hemanth Kumar Beere, Shrish Nath Upadhyay, Nataraj Sanna Kotrappanavar, Srimanta Pakhira, and Debasis Ghosh;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56886–56899 (https://doi.org/10.1021/acsami.2c18872)

Abstract

Vanadium oxyhydroxide has been recently investigated as a starting material to synthesize different phases of vanadium oxides by electrochemical or thermal conversion and has been used as an aqueous zinc-ion battery (AZIB) cathode. However, the low-valent vanadium oxides have poor phase stability under ambient conditions. So far, there is no study on understanding the phase evolution of such low-valent vanadium oxides and their effect on the electrochemical performance toward hosting the Zn2+ ions. The primary goal of the work is to develop a high-performance AZIB cathode, and the highlight of the current work is the insight into the auto-oxidation-induced phase transition of VOOH to V10O24·nH2O under ambient conditions and Zn2+ intercalation behavior thereon as an aqueous zinc-ion battery cathode. Herein, we demonstrate that hydrothermally synthesized VOOH undergoes a phase transition to V10O24·nH2O during both the electrochemical cycling and aerial aging over 38–45 days. However, continued aging till 150 days at room temperature in an open atmosphere exhibited an increased interlayer water content in the V10O24·nH2O, which was associated with a morphological change with different surface area/porosity characteristics and notably reduced charge transfer/diffusion resistance as an aqueous zinc-ion battery cathode. Although the fresh VOOH cathode had impressive specific capacity at rate performance, (326 mAh/g capacity at 0.1 A/g current and 104 mAh/g capacity at 4 A/g current) the cathode suffered from a continuous capacity decay. Interestingly, the aged VOOH electrodes showed gradually decreasing specific capacity with aging at low current and however followed the reverse order at high current. At a comparable specific power of ∼64–66 W/kg, the fresh VOOH and aged VOOH after 60, 120, and 150 days of aging showed the respective energy densities of 208.3, 281.2, 269.2, and 240.6 Wh/kg. Among all the VOOH materials, the 150 day-aged VOOH cathode exhibited the highest energy density at a power density beyond 1000 W/kg. Thanks to the improved kinetics, the 150 day-aged VOOH cathode delivered a considerable energy density of 39.7 Wh/kg with a high specific power of 4466 W/kg. Also, it showed excellent cycling performance with only 0.002% capacity loss per cycle over 20 300 cycles at 10 A/g.

Three-Dimensional Crosslinked PAA-TA Hybrid Binders for Long-Cycle-Life SiOx Anodes in Lithium-Ion Batteries: Weiting Tang, Li Feng, Xiujuan Wei, Guoyong Lai, Haopeng Chen, Zeheng Li, Xiuhuan Huang, Shuxing Wu, and Zhan Lin;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56910–56918 (https://doi.org/10.1021/acsami.2c19344)

Abstract

The large volume expansion hinders the commercial application of silicon oxide (SiOx) anodes in lithium-ion batteries. Recent studies show that binders play a vital role in mitigating the volume change of SiOx electrodes. Herein, we introduce the small molecule tannic acid (TA) with high branching into the linear poly(acrylic acid) (PAA) binder for SiOx anodes. The three-dimensional (3D) crosslinked network with multiple hydrogen bonds is formed by the incorporation of abundant hydroxyl groups with unique carboxyl groups, which increases the interfacial adhesive strength with SiOx particles. As a consequence, SiOx electrodes based on the PAA-TA binder show an excellent cycling performance with a high specific capacity of 1025 mA h g–1 at 500 mA g–1 after 250 cycles. Moreover, the SiOx||NCM811 full cell exhibits a reversible capacity of 143 mA h g–1 corresponding to 87.4% capacity retention after 100 cycles.

A Novel Hierarchical Structure of SnCu2Se4/d-Ti3C2Tx/NPC for a Lithium/Sodium Ion Battery and Hybrid Capacitor with Long-Term Cycling Stabilities: Haoqiang Wang, Yu Wang, Yani Liu, Shuming Dou, Wei Gan, and Qunhui Yuan;  ACS Appl. Mater. Interfaces 2022, 14, 51, 56919–56929 (https://doi.org/10.1021/acsami.2c19347)

Abstract

To alleviate kinetics imbalance and capacity insufficiency simultaneously, a novel hierarchical structure (SnCu2Se4/d-Ti3C2Tx/NPC) composed of delaminated Ti3C2Tx, SnCu2Se4 nanoparticles, and N-doped porous carbon layers is designed as a battery-type anode for lithium/sodium ion hybrid capacitor (LIC/SIC). The combination of SnCu2Se4 nanoparticles with high specific capacity, d-Ti3C2Tx with accelerated ion diffusion path, and NPC with enhanced electronic conductivity makes the SnCu2Se4/d-Ti3C2Tx/NPC composite possess excellent cycling stabilities in half-cell lithium-ion and sodium-ion batteries (LIB and SIB), with capacities of 114 mAh g–1 after 6000 cycles at 10 A g–1 for LIB and 296 mAh g–1 after 900 cycles at 1.0 A g–1 for SIB. The rate performance is also outstanding, with recovered capacity of 738 mAh g–1 at 0.1 A g–1 after cycles at current densities up to 50 A g–1 for LIB. Subsequently, LIC and SIC based on the SnCu2Se4/d-Ti3C2Tx/NPC anode and activated carbon cathode exhibit high energy densities of 147.9 and 158.6 Wh kg–1 at a power density of 100 W kg–1, respectively. They also possess distinctive long lifespans with capacity retentions of 78 and 81% after 10,000 cycles at 1.0 A g–1, respectively, demonstrating the feasibility of SnCu2Se4/d-Ti3C2Tx/NPC toward energy devices requiring high energy density, power density, and long-term stability.

Multi-Scale Computer-Aided Design of Covalent Organic Frameworks for CO2 Capture in Wet Flue Gas: Shuna Yang, Weichen Zhu, Linbin Zhu, Xue Ma, Tongan Yan, Nengcui Gu, Youshi Lan, Yi Huang, Mingyuan Yuan, and Minman Tong;  ACS Appl. Mater. Interfaces 2022, 14, 50, 56353–56362 (https://doi.org/10.1021/acsami.2c17109)

Abstract

Discovery of remarkable porous materials for CO2 capture from wet flue gas is of great significance to reduce the CO2 emissions, but elucidating the most critical structure features for boosting CO2 capture capabilities remains a great challenge. Here, machine-learning-assisted Monte Carlo computational screening on 516 experimental covalent organic frameworks (COFs) identifies the superior secondary building units (SBUs) for wet flue gas separation using COFs, which are tetraphenylporphyrin units for boosting CO2 adsorption uptake and functional groups for boosting CO2/N2 selectivity. Accordingly, 1233 COFs are assembled using the identified superior SBUs. Density functional theory calculation analysis on frontier orbitals, electrostatic potential, and binding energy reveals the influencing mechanism of the SBUs on the wet flue gas separation performance. The “electron-donating-induced vdW interaction” effect is discovered to construct the better-performing COFs, which can achieve high CO2 uptake of 4.4 mmol·g–1 with CO2/N2 selectivity of 104.8. Meanwhile, the “electron-withdrawing-induced vdW + electrostatic coupling interaction” effect is unearthed to construct the better-performing COFs with superior CO2/N2 selectivity, which can reach 277.6 with CO2 uptake of 2.2 mmol·g–1; in this case, H2O plays a positive contribution in improving CO2/N2 selectivity. This work provides useful guidelines for designing optimized two-dimensional-COF adsorbents for wet flue gas separation.

Insights into Capacity Fading Mechanism and Coating Modification of High-Nickel Cathodes in Lithium-Ion Batteries: Hexin Liu, Xiayan Zhao, Yongjia Xie, Shuting Luo, Zhenyu Wang, Lingyun Zhu, and Xing Zhang;  ACS Appl. Mater. Interfaces 2022, 14, 50, 55491–55502 (https://doi.org/10.1021/acsami.2c14235)

Abstract

Developments in electric vehicles and mobile electronic devices are promoting the demand for lithium-ion batteries with higher capacity and longer lifetime. The performances of lithium-ion batteries are crucially affected by cathode materials, among which ternary cathode materials are the most competitive option with the advantages of high capacity, safety, and cost-effectiveness. However, although high-nickel ternary cathode materials can achieve relatively high specific capacity, they generally have unsatisfactory stability during long-term cycling. In this study, the microscopic mechanisms of the cathode failure and the principle of coating modification in lithium-ion batteries have been comprehensively examined. It has been revealed that the irreversible capacity fading is mainly attributed to the interface chemical reaction, which reduces the transition-metal valence states and generates undesired disordered rock-salt phases. This structural phase transformation at the interface induces the dissolution of transition metals and results in irreversible capacity loss of the cathode. To restrain the occurrence of this process, a LiNbO3 coating-modified single-crystal LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material has been prepared. The electrochemical properties as well as the microstructural evolution of the cathode–electrolyte interface during cycling of both the uncoated and coated samples have been comprehensively characterized and compared through impedance spectroscopy testing, SEM-EDX, STEM, and EELS characterization. Additionally, molecular dynamics simulation results confirmed that LiNbO3 coating can effectively inhibit the dissolution of transition metals while providing stable lithium-ion channels. The experimental results also indicate that the coating modification can effectively improve the cycling stability of the NCM811, with the capacity retention rate for 500 cycles increasing from 19% to 70%. This study is helpful to deepen the understanding of the capacity fading mechanisms, and the coating method is effective at maintaining the structural stability and improving the cycle life of lithium-ion batteries.

Unstructured Self-Assembled Molecular Lamella Induces Ultrafast Thermal Transfer through a Cathode/Separator Interphase in Lithium-Ion Batteries:  Jinlong He, Weikang Xian, Lei Tao, Patrick Corrigan, and Ying Li;  ACS Appl. Mater. Interfaces 2022, 14, 50, 56268–56279 (https://doi.org/10.1021/acsami.2c15718)

Abstract

Thermal issues associated with lithium-ion batteries (LIBs) can dramatically affect their life cycle and overall performance. However, the effective heat transfer is deeply restrained by the high thermal resistance across the cathode (lithium cobalt oxide, LCO)–separator (polyethylene, PE) interface. This work presents a new approach to tailoring the interfacial thermal resistance, namely, unstructured self-assembled lamella (USAL). Compared to the popular self-assembled monolayers, although the USAL gives a redundant interface and amorphous molecule patterns, it can also provide many benefits, including easy assembly, more thermal bridges, and ready pressurization. Three small organic molecules (SOMs) were assembled into an LCO–PE interface, providing unique functional groups, −NH2, −SH, and −CH3, to illustrate its energy conversion efficiency. Through molecular dynamics simulations, our results show that the USAL can facilitate interfacial heat transfer remarkably. A 3-aminopropyl trimethoxysilane (APTMS)-coated LCO–PE system with 11.4 Å thickness demonstrates the maximum enhancement of thermal conductance, about 320% of the pristine system. Such enhancement is attributed to the developed double heat passages by strong non-bonded interactions across LCO–SOM and PE–SOM interfaces, a tuned temperature field, and high compatibility between SOMs and PE. Importantly, due to SOMs’ amorphous morphology, the pressure can be imposed and further enhance the interfacial heat transfer. Results show the improved thermal conductance rises the most for the APTMS-coated LCO–PE system with 11.4 Å thickness at 10 GPa, almost 685% higher than that of the pristine system. The high efficiency of heat transfer comes as a result of the enhanced binding strength across the LCO–SOM and SOM–PE interface, the reduced phonon scattering in PE and SOMs, and the high LCO stiffness. These investigations are expected to provide a new perspective for modulating the heat transfer across the interphase of LIBs and achieve more effective thermal management for the multi-material system.

In Situ Formed Core–Shell LiZnxMn2–xO4@ZnMn2O4 as Cathode for Li-Ion Batteries: Wangqiong Xu, Chengzhen Song, Ruijuan Qi, Yonghui Zheng, Yuning Wu, Yan Cheng, Hui Peng, Hechun Lin, and Rong Huang;  ACS Appl. Mater. Interfaces 2022, 14, 50, 55528–55537 (https://doi.org/10.1021/acsami.2c15783)

Abstract

Elemental doping and surface modification are commonly used strategies for improving the electrochemical performance of LiMn2O4, such as the rated capacity and cycling stability. In this study, in situ formed core–shell LiZnxMn2–xO4@ZnMn2O4 cathodes are prepared by tuning the Zn-doping content. Through comprehensive microstructural analyses by the spherical aberration-corrected scanning transmission microscopy (Cs-STEM) technique, we shed light on the correlation between the microstructural configuration and the electrochemical performance of Zn-doped LiMn2O4. We demonstrate that part of Zn2+ ions dope into the spinel to form LiZnxMn2–xO4 in bulk and other Zn2+ ions occupy the 8a sites of the spinel to form the ZnMn2O4 shell on the outermost surface. This in situ formed core–shell LiZnxMn2–xO4@ZnMn2O4 contributes to better structural stabilization, presenting a superior capacity retention ratio of 95.8% after 700 cycles at 5 C at 25 °C for the optimized sample (LiZn0.02Mn1.98O4), with an initial value of 80 mAh g–1. Our investigations not only provide an effective way toward high-performance LIBs but also shed light on the fundamental interplay between the microstructural configuration and the electrochemical performance of Zn-doped spinel LiMn2O4.

A Critical Outlook on Lignocellulosic Biomass and Plastics Co-Gasification: A Mini-Review.:  Ankush Halba, Sonal K. Thengane, and Pratham Arora;  Energy Fuels 2023, 37, 1, 19–35 (https://doi.org/10.1021/acs.energyfuels.2c02907)

Abstract

The generation of solid waste and lignocellulosic biomass (LCB) residues and their environmentally responsible disposal have emerged as major global challenges. A major part (around 12%) of solid waste is plastic, and the increased accumulation has become a serious public health and environmental hazard. For the combined management of residual LCB biomass and plastic waste, thermochemical conversion, particularly gasification, appears to be a potential alternative. Gasification is a process that turns high carbon-containing solid feedstocks into a combustible gas mixture known as syngas or producer gas based on the gasifying agent. Co-gasification (the gasification of two distinct feedstocks) has the potential to facilitate eco-friendly plastic waste disposal while also contributing to the production of green energy. The literature on the co-gasification of LCB and plastic waste is reviewed in the current study. These are mostly experimental studies on biomass and plastics carried out in various reactors with multiple gasifying mediums. The synergistic effects of various feedstock compositions and attributes are examined during co-gasification using experimental studies and reactor-level modeling. The impacts of operating parameters on the gas yield, tar formation, and gasifier performance are also analyzed. Finally, the challenges, research gaps, and the way toward commercialization in the context of co-gasification of various combinations of LCB and plastics are presented.

Toward Native Hardwood Lignin Pyrolysis: Insights into Reaction Energetics from Density Functional Theory: Tanzina Azad, Maria L. Auad, Thomas Elder, and Andrew J. Adamczyk; Energy Fuels 2023, 37, 1, 401–423 (https://doi.org/10.1021/acs.energyfuels.2c03025)

Abstract

Lignin is one of the three structural components of lignocellulosic biomass and the only renewable source for sustainably producing aromatic chemicals. Despite lignin’s promise for targeted valorization to fine chemicals, fuels, and polymer composites, a major roadblock is an ambiguity associated with its molecular structure. Due to the lack of an established molecular structure, all types of computational studies from reaction mechanism to reaction energetics are performed with model lignin compounds. Among several thermochemical conversion techniques, lignin pyrolysis has been an active research area for both experimental and computational investigations. Historically, computational studies on the pyrolysis of lignin have mainly been limited to dimeric or trimeric models using electronic structure methods. Very recently, model oligomers up to the size of decamers have been studied with density functional theory (DFT) calculations. While these studies used very simplified models to study lignin’s pyrolysis behavior, theoretical investigations on a more realistic lignin structure are warranted to advance its state-of-the-art. To address this, we have modeled a native hardwood lignin polymer consisting of 20 repeating units, including all three monolignols, i.e., guaiacyl (G), syringyl (S), and p-hydroxy coumaryl (H) units, and multiple types of linkages, i.e., β-O-4, 4-O-5, β–β, and β-5. This more realistic molecular model for the wild-type poplar lignin is based on a proposed lignin structure reported in a previous experimental study. The initial stage in lignin pyrolysis involves the homolytic cleavage of β-O-4 linkages present in lignin. The activation energy for homolysis of this linkage is considered to be slightly greater than the bond dissociation enthalpy (BDE) required to cleave it. We used a composite method using molecular mechanics-based conformational sampling and quantum mechanically based density functional theory (DFT) calculations to determine the reaction energetics for this reaction, which indicates the activation energy required for the early stage of lignin pyrolysis. In addition, we calculated standard thermodynamic properties for all species, including enthalpy of formation, heat capacity, entropy, and Gibbs free energy of formation as a function of temperature. This study provides the reaction energetics and standard thermodynamic quantities that could be used in kinetic and reactor modeling for biomass conversion. Additionally, these predictions would be particularly helpful in advanced-generation biorefinery, where hardwoods can be used as a potential feedstock. Moreover, the predictions reported in this study will benefit further computational studies and cross-validation with pyrolysis experiments, ultimately contributing to solving the puzzle of the structural ambiguity of lignin.

Truncated Octahedral Shape of Spinel LiNi0.5Mn1.5O4 via a Solid-State Method for Li-Ion Batteries: Jotti Karunawan, Putri Nadia Suryadi, Lauqhi Mahfudh, Sigit Puji Santosa, Afriyanti Sumboja, and Ferry Iskandar;  Energy Fuels 2023, 37, 1, 754–762 (https://doi.org/10.1021/acs.energyfuels.2c03507)

Abstract

Spinel cathode LiNi0.5Mn1.5O4 (LNMO) has attracted high interest owing to its high-energy-density, cobalt-free, and high-voltage operation. For further application, the solid-state method as the simpler parameter control is favorable for scalable synthesis of LNMO cathode materials. However, the solid-state method has the disadvantage of producing irregular particle shapes that form the non-uniform cathode-electrolyte interphase, leading to the low cycle stability of the batteries. Here, we investigate the effective synthesis route of LNMO cathode materials via a solid-state method that can produce a regular truncated octahedral shape. The route of adding a Li-source (i.e., LiOH) to the transition metal in the oxide phase after the first heat treatment is proven to effectively produce a regular truncated octahedral shape that affects high specific capacity, long-term stability, and high-rate performance. The LNMO produced via this route synthesis showed a specific capacity of 128.53 mA h/g at a current density of 0.1 C. After 250 cycles, the truncated octahedral shape LNMO still possessed excellent cycling performance, 90.32% 3–4.8 V at 0.5 C. These results showed that this route is an effective way for the scalable and easy solid-state synthesis of the truncated octahedral shape of high-performance spinel LNMO cathode materials.

Photo-Assisted Catalytic CO2 Hydrogenation to CO with Nearly 100% Selectivity over Rh/TiO2 Catalysts: Yunxiang Tang, Simeng Wu, Yanxiang Wang, Lixiang Song, Zhengyi Yang, Chan Guo, Jiurong Liu, and Fenglong Wang;  Energy Fuels 2023, 37, 1, 539–546 (https://doi.org/10.1021/acs.energyfuels.2c03604)

Abstract

Photo-assisted catalytic CO2 hydrogenation represents a promising route to convert CO2 into value-added chemicals under mild conditions, but challenges remain in the design and development of highly active and selective catalysts. Herein, we synthesized highly efficient catalysts comprising Rh nanoparticles supported on TiO2 nanosheets for photo-assisted catalytic CO2 hydrogenation, which achieved a high CO production rate of 20.6 mmol gcat–1 h–1 (5.15 mol gRh–1 h–1) with nearly 100 % selectivity and excellent stability at 250 °C under light irradiation, outperforming most reported metal-based catalysts. X-ray photoelectron spectroscopy revealed that the electrons transfer from Rh nanoparticles to TiO2, hinting a strong interaction between Rh and the TiO2 support. Under illumination, the accumulated hot electrons on TiO2 surfaces could effectively promote the activation of CO2 molecules. In situ diffuse reflectance infrared Fourier transform spectroscopy results revealed that formate was the critical intermediate in the reverse water–gas shift reaction process, and light irradiation could effectively facilitate the activation and conversion of reactants and intermediate species, thereby improving CO production. This work provides a new strategy for the integration of solar and thermal energy for an efficient RWGS reaction under mild conditions.

Coupling Nonstoichiometric Zn0.76Co0.24S with NiCo2S4 Composite Nanoflowers for Efficient Synergistic Electrocatalytic Oxygen and Hydrogen Evolution Reactions: Rathindranath Biswas, Pooja Thakur, Imtiaz Ahmed, Tanmay Rom, Mir Sahidul Ali, Ranjit A. Patil, Bhupender Kumar, Shubham Som, Deepak Chopra, Avijit Kumar Paul, Yuan-Ron Ma, and Krishna Kanta Haldar;  Energy Fuels 2023, 37, 1, 604–613 (https://doi.org/10.1021/acs.energyfuels.2c03384)

Abstract

Transition-metal sulfide-based composite nanomaterials have garnered extensive interest not only for their unique morphological architectures but also for exploring as a noble-metal-free cost-effective, durable, and highly stable catalyst for electrochemical water splitting. In this work, we synthesized in situ nonstoichiometric Zn0.76Co0.24S with NiCo2S4 binary composite flowers (Zn0.76Co0.24S/NiCo2S4) in one step by thermal decomposition of Zn2[PDTC]4 and Ni[PDTC]2 complexes by a solvothermal process in a nonaqueous medium from their molecular precursor, and their potential application in electrochemical oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) was investigated. Field-emission scanning electron microscopy and transmission electron microscopy analyses revealed the flower-shaped morphology of as-synthesized Zn0.76Co0.24S/NiCo2S4. Again, the structural and chemical compositions were confirmed through powder X-ray diffraction and X-ray photoelectron spectroscopy studies, respectively. The as-obtained 3D flower-type Zn0.76Co0.24S/NiCo2S4 nanostructure was further subject to electrochemical OER and HER in alkaline and acidic media, respectively. Zn0.76Co0.24S/NiCo2S4 showed low overpotential values of 248 mV (Tafel slope, 85 mV dec–1) and 141 mV (Tafel slope, 79 mV dec–1) for OER and HER activities, respectively, due to the synergistic effects of Zn0.76Co0.24S and NiCo2S4. Several long-term stability tests also affirmed that the Zn0.76Co0.24S/NiCo2S4 composite nanostructure is a highly stable and efficient electrocatalyst toward OER and HER activities as compared to the recently reported superior bifunctional electrocatalysts as well as state-of-the-art materials.

Introducing Oxygen Vacancies and Ti3+ on Rh/TiO2 via Plasma Treatment for CO Hydrogenation to Ethanol: Zhenyu Wang, Shoushuai Tian, Junxin Guo, and Zhao Wang; Energy Fuels 2023, 37, 1, 214–221 (https://doi.org/10.1021/acs.energyfuels.2c03018)

Abstract

Rh-based catalysts are widely used in CO hydrogenation to ethanol. In this work, Rh/TiO2 catalysts were prepared by glow discharge plasma. Rhodium salt was reduced by electrons in an electric field at room temperature. Oxygen vacancies and Ti3+ were produced on the surface of Rh/TiO2 by plasma. The defects promoted the synergistic effect of Rh and TiO2 through the enhanced interaction between active metal and supporter. Ti3+ is beneficial for the adsorption of intermediate formyl group. In situ IR revealed that the bridged and linear adsorption mechanisms of CO can promote the formation of ethanol intermediates. Rh/TiO2 catalysts by plasma exhibited a superior space-time yield of 0.106 gMeOH·gcat–1 h–1, at 260 °C and 3 MPa, which was approximately 1.8 times that by traditional hydrogen reduction.

Feasibility Analysis of Coupling Hydrogen-Derived Fuel on a Coal-Fired Boiler for Power Generation: Qiaopeng Yao, Ruiyu Li, Yikun Wang, Yuhang Li, Lei Zhang, Lei Deng, and Defu Che;  Energy Fuels 2023, 37, 1, 477–491 (https://doi.org/10.1021/acs.energyfuels.2c03079)

Abstract

As an alternative to hydrogen, hydrogen-derived fuel (NH3, CH3OH, or CH3OCH3) is considered to be an ideal secondary energy source. The effects of coupling hydrogen-derived fuels with coal on the thermodynamic parameters of a boiler are analyzed through thermal calculations according to the principles of mass and energy conservation. A 300 MW tangentially fired boiler is selected for a case study. The results show that the variations of boiler thermodynamic parameters depend on the properties of hydrogen-derived fuels and coupling mass percentage. After the coupling, the furnace exit flue gas temperature changes, which results in alterations in heat distribution of radiation and convection for the water-cooled walls and the convective heating surfaces. The furnace exit flue gas temperature drops for coupling H2 or NH3 but rises for coupling CH3OH or CH3OCH3 with the growth of the coupling mass percentage. The variations of boiler thermal efficiency with different coupling mass percentages under BMCR load are 0.55% to 0.90% for H2, −0.32% to −1.16% for NH3, −0.22% to −2.03% for CH3OH, and −0.08% to −0.59% for CH3OCH3. The acid dew point rises and then drops as the coupling mass percentage grows. The flow rate of the total flue gas increases at the outlet of the air preheater. Thus, the current forced draft fan could not meet the requirements, and its retrofit should be performed. After the large proportion of cofiring, the coal consumption rate drops. The annual emissions reductions of CO2 are up to 0.734 million tons for H2, 0.231 million tons for NH3, 0.062 million tons for CH3OH, and 0.101 million tons for CH3OCH3 under BMCR load at a 20% coupling mass percentage. The lifecycle CO2 reduction potential should be considered for better illustrating the benefits of cocombustion in future studies.

A Minireview of the Influence of CO2 Injection on the Pore Structure of Reservoir Rocks: Advances and Outlook: Hui Gao, Yonggang Xie, Zhilin Cheng, Chen Wang, Teng Li, Xiulan Zhu, Kaiqing Luo, Jiangfeng Cao, and Ning Li;  Energy Fuels 2023, 37, 1, 118–135 (https://doi.org/10.1021/acs.energyfuels.2c03328)

Abstract

The recoverable hydrocarbon reserves of conventional oil and gas resources are very limited in China. As important alternative resources, unconventional oil and gas have become a research hotspot. Though tight reservoirs have great potential to alleviate the increasing demand, issues during the development process, such as the rapid pressure depletion, fast decline in production, low productivity, and difficulties in water injection, are usually encountered due to poor physical properties like small pore throats and strong heterogeneity of the pore structure. The CO2 flooding technique could effectively replace crude oil from micro-nanopores, which is considered as a promising way to enhance the development performance of tight oil. However, precipitation and dissolution phenomena usually occur along with the CO2 injection process into reservoirs, affecting the pore structure evolution and oil displacement efficiency. In addition, artificial and natural fractures will even make this process more complicated. This paper presents the commonly used experimental approaches for CO2 injection into tight reservoirs and summarizes the main methods for investigating the influence of CO2 injection on the pore structure of reservoir rocks. Based on this, we highlighted that more attention should be paid to the influence of fractures and their dynamic changes on the evolution of pore structure during CO2 injection and the study of the solid–liquid interactions. To establish a method that could quantitatively evaluate the full-scale evolution of pore throats after CO2 injection is necessary. Meanwhile, the interaction strength of precipitation and dissolution and their effects on pore structure also remain open. Finally, a rigorous framework that could reveal the evolution mechanism and characterize the multiscale pore structure involving multiple influencing factors is urgently warranted.

Solar-Driven Hydrogen Production: Recent Advances, Challenges, and Future Perspectives: Hui Song, Shunqin Luo, Hengming Huang, Bowen Deng, and Jinhua Ye;  ACS Energy Lett. 2022, 7, 3, 1043–1065 (https://doi.org/10.1021/acsenergylett.1c02591)

Abstract

Solar H2 production is considered as a potentially promising way to utilize solar energy and tackle climate change stemming from the combustion of fossil fuels. Photocatalytic, photoelectrochemical, photovoltaic–electrochemical, solar thermochemical, photothermal catalytic, and photobiological technologies are the most intensively studied routes for solar H2 production. In this Focus Review, we provide a comprehensive review of these technologies. After a brief introduction of the principles and mechanisms of these technologies, the recent achievements in solar H2 production are summarized, with a particular focus on the high solar-to-H2 (STH) conversion efficiency achieved by each route. We then comparatively analyze and evaluate these technologies based on the metrics of STH efficiency, durability, economic viability, and environmental sustainability, aiming to assess the commercial feasibility of these solar technologies compared with current industrial H2 production processes. Finally, the challenges and prospects of future research on solar H2 production technologies are presented.

Impact of Gas–Solid Reaction Thermodynamics on the Performance of a Chemical Looping Ammonia Synthesis Process: Reinaldo Juan Lee Pereira, Wenting Hu, and Ian S. Metcalfe;  Energy Fuels 2022, 36, 17, 9757–9767 (https://doi.org/10.1021/acs.energyfuels.2c01372)

Abstract

Novel ammonia catalysts seek to achieve high reaction rates under milder conditions, which translate into lower costs and energy requirements. Alkali and alkaline earth metal hydrides have been shown to possess such favorable kinetics when employed in a chemical looping process. The materials act as nitrogen carriers and form ammonia by alternating between pure nitrogen and hydrogen feeds in a two-stage chemical looping reaction. However, the thermodynamics of the novel reaction route in question are only partially available. Here, a chemical looping process was designed and simulated to evaluate the sensitivity of the energy and economic performance of the processes toward the appropriate gas–solid reaction thermodynamics. Thermodynamic parameters, such as reaction pressure and especially equilibrium ammonia yields, influenced the performance of the system. In comparison to a commercial ammonia synthesis unit with a 28% yield at 150 bar, the chemical looping process requires a yield greater than 38% to achieve similar energy consumptions and a yield greater than 26% to achieve similar costs at a given temperature and 150 bar. Entropies and enthalpies of formation of the following pairs were estimated and compared: LiH/Li2NH, MgH2/MgNH, CaH2/CaNH, SrH2/SrNH, and BaH2/BaNH. Only the LiH/Li2NH pair has satisfied the given criteria, and initial estimates suggest that a 62% yield is obtainable.

3D Modeling of the Solidification Structure Evolution and of the Inter Layer/Track Voids Formation in Metallic Alloys Processed by Powder Bed Fusion Additive Manufacturing:  Laurentiu Nastac; Materials 2022, 15(24), 8885; https://doi.org/10.3390/ma15248885

Abstract

A fully transient discrete-source 3D Additive Manufacturing (AM) process model was coupled with a 3D stochastic solidification structure model to simulate the grain structure evolution quickly and efficiently in metallic alloys processed through Electron Beam Powder Bed Fusion (EBPBF) and Laser Powder Bed Fusion (LPBF) processes. The stochastic model was adapted to rapid solidification conditions of multicomponent alloys processed via multi-layer multi-track AM processes. The capabilities of the coupled model include studying the effects of process parameters (power input, speed, beam shape) and part geometry on solidification conditions and their impact on the resulting solidification structure and on the formation of inter layer/track voids. The multi-scale model assumes that the complex combination of the crystallographic requirements, isomorphism, epitaxy, changing direction of the melt pool motion and thermal gradient direction will produce the observed texture and grain morphology. Thus, grain size, morphology, and crystallographic orientation can be assessed, and the model can assist in achieving better control of the solidification microstructures and to establish trends in the solidification behavior in AM components. The coupled model was previously validated against single-layer laser remelting IN625 experiments performed and analyzed at National Institute of Standards and Technology (NIST) using LPBF systems. In this study, the model was applied to predict the solidification structure and inter layer/track voids formation in IN718 alloys processed by LPBF processes. This 3D modeling approach can also be used to predict the solidification structure of Ti-based alloys processes by EBPBF.

The Mechanical Properties of Aluminum Metal Matrix Composites Processed by High-Pressure Torsion and Powder Metallurgy:  Mohamed Ibrahim Abd El Aal, Hossam Hemdan El-Fahhar, Abdelkarim Yousif Mohamed  and  Elshafey Ahmed Gadallah; Materials 2022, 15(24), 8827; https://doi.org/10.3390/ma15248827

Abstract

Al-Al2O3 and SiC metal matrix composites (MMCs) samples with different volume fractions up to 20% were produced by high-pressure torsion (HPT) using 10 GPa for 30 revolutions of Al-Al2O3, and SiC and powder metallurgy (PM). The effect of the processing method of micro-size Al MMCs on the density, microstructure evolution, mechanical properties, and tensile fracture mode was thoroughly investigated. HPT processing produces fully dense samples relative to those produced using powder metallurgy (PM). The HPT of the Al MMCs reduces the Al matrix grain size and fragmentation of the reinforcement particles. The Al matrix average grain size decreased to 0.39, 0.23, and 0.2 µm after the HPT processing of Al, Al-20% Al2O3, and SiC samples. Moreover, Al2O3 and SiC particle sizes decreased from 31.7 and 25.5 µm to 0.15 and 0.13 µm with a 99.5% decrease. The production of ultrafine grain (UFG) composite samples effectively improves the microhardness and tensile strength of the Al and Al MMCs by 31–88% and 10–110% over those of the PM-processed samples. The good bonding between the Al matrix and reinforcement particles noted in the HPTed Al MMCs increases the strength relative to the PM samples. The tensile fracture surface morphology results confirm the tensile properties results.

Research Progress of Steels for Nuclear Reactor Pressure Vessels: Linjun Zhou,  Jie Dai, Yang Li, Xin Dai, Changsheng Xie, Linze Li  and  Liansheng Chen;  Materials 2022, 15(24), 8761; https://doi.org/10.3390/ma15248761

Abstract

The nuclear reactor pressure vessel is an important component of a nuclear power plant. It has been used in harsh environments such as high temperature, high pressure, neutron irradiation, thermal aging, corrosion and fatigue for a long time, which puts forward higher standards for the performance requirements for nuclear pressure vessel steel. Based on the characteristics of large size and wall thickness of the nuclear pressure vessel, combined with its performance requirements, this work studies the problems of forging technology, mechanical properties, irradiation damage, corrosion failure, thermal aging behavior and fatigue properties, and summarizes the research progress of nuclear pressure vessel materials. The influencing factors of microstructures evolution and mechanism of mechanical properties change of nuclear pressure vessel steel are analyzed in this work. The mechanical properties before and after irradiation are compared, and the influence mechanisms of irradiation hardening and embrittlement are also summarized. Although the stainless steel will be surfacing on the inner wall of nuclear pressure vessel to prevent corrosion, long-term operation may cause aging or deterioration of stainless steel, resulting in corrosion caused by the contact between the primary circuit water environment and the nuclear pressure vessel steel. Therefore, the corrosion behavior of nuclear pressure vessels materials is also summarized in detail. Meanwhile, the evolution mechanism of the microstructure of nuclear pressure vessel materials under thermal aging conditions is analyzed, and the mechanisms affecting the mechanical properties are also described. In addition, the influence mechanisms of internal and external factors on the fatigue properties, fatigue crack initiation and fatigue crack propagation of nuclear pressure vessel steel are analyzed in detail from different perspectives. Finally, the development direction and further research contents of nuclear pressure vessel materials are prospected in order to improve the service life and ensure safe service in harsh environment.