Recovery and Utilization of Electrolytic Manganese Anode Slime for the High-Value Industrialized Products─A Review: Tianyu Zhang, Jiancheng Shu, Mengjun Chen, Liang Wei, and Yong Yang; Ind. Eng. Chem. Res. 2023, XXXX, XXX, XXX-XXX, Publication Date:August 10, 2023 (https://doi.org/10.1021/acs.iecr.3c00960)

Abstract

The high-value recovery and utilization of electrolytic manganese anode slime (EMAS) have emerged as a pressing concern in the global electrolytic manganese industry. EMAS, a black-brown byproduct generated during the electrolytic process of manganese metal, contains over 40% Mn as well as heavy metals, such as Pb and Se. This Review delves into the status of research pertaining to the properties of EMAS as a resource, waste reduction strategies, and resource utilization both at home and abroad. The resource reduction technology of EMAS focuses primarily on modifying titanium-coated electrolytic manganese anode plates, adding additives, regulating electric currents, and developing advanced electrolytic equipment. The resource utilization technology, on the other hand, centers around the recovery and separation of Mn, Pb, and Se to generate MnO2, LiMn2O4, high-purity MnSO4, adsorbent, catalyst, and oxidant products. Furthermore, this Review points out the existing issues and future development prospects of EMAS. The research results of this Review will provide technical support for global EMAS comprehensive resource utilization and manganese pollution treatment in electrolytic manganese enterprises.

Data-Driven Quantitative Intrinsic Hazard Criteria for Nanoproduct Development in a Safe-by-Design Paradigm: A Case Study of Silver Nanoforms: Irini Furxhi, Rossella Bengalli, Giulia Motta, Paride Mantecca, Ozge Kose, Marie Carriere, Ehtsham Ul Haq, Charlie O’Mahony, Magda Blosi, Davide Gardini, and Anna Costa;  ACS Appl. Nano Mater. 2023, 6, 5, 3948–3962 (https://doi.org/10.1021/acsanm.3c00173)

Abstract

The current European (EU) policies, that is, the Green Deal, envisage safe and sustainable practices for chemicals, which include nanoforms (NFs), at the earliest stages of innovation. A theoretically safe and sustainable by design (SSbD) framework has been established from EU collaborative efforts toward the definition of quantitative criteria in each SSbD dimension, namely, the human and environmental safety dimension and the environmental, social, and economic sustainability dimensions. In this study, we target the safety dimension, and we demonstrate the journey toward quantitative intrinsic hazard criteria derived from findable, accessible, interoperable, and reusable data. Data were curated and merged for the development of new approach methodologies, that is, quantitative structure–activity relationship models based on regression and classification machine learning algorithms, with the intent to predict a hazard class. The models utilize system (i.e., hydrodynamic size and polydispersity index) and non-system (i.e., elemental composition and core size)-dependent nanoscale features in combination with biological in vitro attributes and experimental conditions for various silver NFs, functional antimicrobial textiles, and cosmetics applications. In a second step, interpretable rules (criteria) followed by a certainty factor were obtained by exploiting a Bayesian network structure crafted by expert reasoning. The probabilistic model shows a predictive capability of ≈78% (average accuracy across all hazard classes). In this work, we show how we shifted from the conceptualization of the SSbD framework toward the realistic implementation with pragmatic instances. This study reveals (i) quantitative intrinsic hazard criteria to be considered in the safety aspects during synthesis stage, (ii) the challenges within, and (iii) the future directions for the generation and distillation of such criteria that can feed SSbD paradigms. Specifically, the criteria can guide material engineers to synthesize NFs that are inherently safer from alternative nanoformulations, at the earliest stages of innovation, while the models enable a fast and cost-efficient in silico toxicological screening of previously synthesized and hypothetical scenarios of yet-to-be synthesized NFs.

Influence of Pd(II) Adsorption on High-Temperature Ferroelastic Phase Transition in (2-Amino-2-thiazolinium)PbBr3: Yan Xu, Ke Xu, Lei He, Ti-Jian Yin, Jie Mu, Jin-Tao Men, Wen Zhang, and Qiong Ye;  Inorg. Chem. 2023, 62, 3, 1279–1285 (https://doi.org/10.1021/acs.inorgchem.2c04163)

Abstract

Ferroelastic materials have received special attention because of their great promise for mechanical switches, piezoelectric sensors, and data storage applications. Here, we report a novel ferroelastic semiconducting hybrid organic–inorganic perovskite (C3H7N2S)PbBr3 (1) [(C3H7N2S) is 2-amino-2-thiazolinium] with a ferroelastic phase transition at 395 K and an optical band gap of 3.43 eV. 1 has a one-dimensional BaNiO+3-type structure and undergoes a high-temperature ferroelastic phase transition with an Aizu notation of mmmF2/m. Meanwhile, 1 exhibits dielectric switch near the phase transition temperature. By introducing the thioether group, the motion of the molecules or ions of 1 is hindered after the sorption of Pd(II) metal ions, which leads to the disappearance of the high-temperature ferroelastic phase transition and dielectric switch. This is the first reported ferroelastic semiconductor material with Pd(II) adsorption property, by studying the influence of Pd(II) adsorption on high-temperature ferroelastic phase transition, it may be enlightening to further uncover the mechanism of phase transition or the origin of ferroelasticity, which represents an important step toward multifunctional applications of lead-hybrid perovskite-based ferroelastic materials.

Inverse Oxide/Metal Catalysts for CO2 Hydrogenation to Methanol: Kashala Fabrice Kapiamba, Kashala Fabrice Kapiamba, Hope O. Otor, Sridhar Viamajala, and Ana C. Alba-Rubio;  Energy Fuels 2022, 36, 19, 11691–11711 (https://doi.org/10.1021/acs.energyfuels.2c02131)

Abstract

The hydrogenation of CO2 to methanol using heterogeneous catalysts is an appealing route for mitigating greenhouse gas emissions and generating useful products. The synthesis of methanol is attractive due to its utilization as a fuel, a fuel additive, or an intermediate for a wide array of industrial chemicals. Traditional catalytic systems, like those based on Cu or Ni, have been extensively explored but have thus far shown limited conversion and selectivity to desired products like methanol primarily due to the chemical stability of CO2. These catalysts are also difficult to use industrially due to the high pressures and temperatures needed for these catalytic reactions. In the search for improvements in the reaction rates, conversion, and selectivity to liquid products, inverse oxide/metal catalysts have been recently explored and have yielded promising results. This review summarizes the latest advances in the use of inverse catalysts for the hydrogenation of CO2 to methanol. First, this review focuses on some strategies for synthesizing inverse oxide/metal catalysts. Next, the relationship between the interfacial properties and the catalytic activity is reviewed, emphasizing the nature of the oxide layer and its dispersion on the metal surface. Lastly, the activities of inverse catalysts and materials prepared by traditional synthesis approaches are compared.

Theoretical Screening of CO2 Electroreduction over MOF-808-Supported Self-Adaptive Dual-Metal-Site Pairs: Wenjuan Xue, Jian Li, Hongliang Huang, Weiwei Zhang, and Donghai Mei;  Inorg. Chem. 2023, 62, 2, 930–941 (https://doi.org/10.1021/acs.inorgchem.2c03734)

Abstract

Electrochemical CO2 reduction to transportation fuels and valuable platform chemicals provides a sustainable avenue for renewable energy storage and realizes an artificially closed carbon loop. However, the rational design of highly active and selective CO2 reduction electrocatalysts remains a challenging task. Herein, a series of metal–organic framework (MOF)-supported flexible, self-adaptive dual-metal-site pairs (DMSPs) including 21 pairwise combinations of six transition metal single sites (MOF-808-EDTA-M1M2, M1/M2 = Fe, Cu, Ni, Pd, Pt, Au) for the CO2 reduction reaction (CO2RR) were theoretically screened using density functional theory calculations. Against the competitive hydrogen evolution reaction, MOF-808-EDTA-FeFe and MOF-808-EDTA-FePt were identified as the promising CO2RR electrocatalysts toward C1 and C2 products. The calculated limiting potential for CO2 electroreduction to C2H6 and C2H5OH over MOF-808-EDTA-FeFe is −0.87 V. Compared with an applied potential of −0.56 eV toward CH4 production over MOF-808-EDTA-FeFe, MOF-808-EDTA-FePt exhibits an even better activity for CO2 reduction to C1 products at a limiting potential of −0.35 V. The present work not only identifies promising candidates for highly selective CO2RR electrocatalysts leading to C1 and C2 products but also provides mechanistic insights into the dynamic nature of DMSPs for stabilizing various reaction intermediates in the CO2RR process.

Recent Progress in Transition-Metal Sulfide Catalyst Regulation for Improved Oxygen Evolution Reaction: Runze He, Xingyu Huang, and Ligang Feng;  Energy Fuels 2022, 36, 13, 6675–6694 (https://doi.org/10.1021/acs.energyfuels.2c01429)

Abstract

Electrochemical hydrogen production is considered the most reliable approach to transfer the renewable energies to the chemical energy─namely, the hydrogen─for storage, and intensive attention has been directed to the nonprecious catalyst development for water splitting reactions. Among the catalyst candidates, metal sulfides have been extensively explored as an emerging electrocatalyst material for oxygen evolution reaction (OER) in water splitting reaction, because of their abundant active centers, good electrical conductivity, and high intrinsic activity. By optimizing the structure and chemical states, some advanced catalysts have been reported recently, which was instructive and inspiring for novel catalyst development. Herein, the recent advances in electrocatalytic performance and optimization strategies of transition-metal sulfide for OER are reviewed systematically and comprehensively. The fundamental catalytic mechanism and key parameters of OER are first presented and then followed by the physicochemical properties of metal sulfides, which could be helpful in understanding the correlation between the structure and catalytic performance. Importantly, the intrinsic activity of metal sulfides boosted by the general strategies, in terms of the defect/vacancy effect, lattice mismatch, phase engineering, heterostructure, and the doping effect, is mainly discussed in this work. The challenges and opportunities related to the further development of metal sulfide materials with high activity and long-term durability are finally proposed. It can be concluded that these regulatory strategies could largely improve the electrocatalytic performance by increasing the active site exposure and reducing the energy barrier of catalytic reactions. In addition, the problems and future challenges in improving the catalytic performance of metal sulfide materials are presented, which provides beneficial enlightenment and guidance for the development of efficient and low-cost electrocatalysts in the future. Hopefully, this effort would be helpful to the design and preparation of metal sulfides catalyst for OER.

Anionic Redox Chemistry for Sodium-Ion Batteries: Mechanisms, Advances, and Challenges: Quan Wu, Tong Zhang, Jiarun Geng, Suning Gao, Hua Ma, and Fujun Li; Energy Fuels 2022, 36, 15, 8081–8095 (https://doi.org/10.1021/acs.energyfuels.2c01601)

Abstract

The increasing reliance on energy demands has called for continual improvement of sodium-ion batteries (SIBs) due to the abundant Na resources and low cost. Na-based layered transition metal oxides (TMOs) are promising cathode materials due to their unique structural characteristics that provide two-dimensional (2D) ion diffusion channels and maintain structural integrity during the extraction and insertion of Na-ions. However, the energy density of conventional TMO cathodes is mainly limited by cationic redox reactions. Activating anionic redox (O2–/On–) for additional capacity in TMO cathodes is promising to improve the energy density of SIBs, though the chemistry of anionic redox reaction (ARR) is still unclear. This overview focuses on the underlying science, development, and latest advances of ARR in SIBs. The challenges and possible approaches are discussed in light of ARR reversibility and voltage hysteresis. This review will provide insights on improving the energy density of advanced TMOs cathodes with ARR activity.

Unraveling the Role of Defects in Electrocatalysts for Water Splitting: Recent Advances and Perspectives : Liuchen Wang, Chaoxia Peng, Haoqing Lin, and Bote Zhao;  Energy Fuels 2022, 36, 19, 11660–11690 (https://doi.org/10.1021/acs.energyfuels.2c02017)

Abstract

The development of highly efficient and robust electrocatalysts plays a crucial role in the success of sustainable energy conversion technologies, like electrochemical water splitting for hydrogen production. Defect engineering has been considered as an effective strategy to tune the electrocatalysts and enhance the activity. This review covers recent advances in engineering, probing, and understanding the defects in electrocatalysts toward the hydrogen evolution reaction and oxygen evolution reaction. In particular, the role of defects in electrocatalysts have been comprehensively discussed and summarized on the basis of both experimental results and theoretical calculations. We further provide a summary of the computational insight into the role of defects. Finally, we propose the critical challenges and corresponding future directions.

Staged Pyrolytic Conversion of Acid-Loaded Woody Biomass for Production of High-Strength Coke and Valorization of Volatiles: Fu Wei, Shinji Kudo, Shusaku Asano, and Jun-ichiro Hayashi; Energy Fuels 2022, 36, 13, 6949–6958 (https://doi.org/10.1021/acs.energyfuels.2c01352)

Abstract

Lignocellulosic biomass is an attractive resource for metallurgical coke. The hot pelletization of powdered biomass followed by carbonization produces a high-strength biocoke. However, the fate of a major portion of biomass after carbonization is the production of low-value volatiles. Here, we enabled the valorization of woody biomass as valuable chemicals, such as anhydrosugars and phenols, and strong coke by loading mineral acid over wood and staged conversion consisting mainly of torrefaction, pelletization, and then carbonization. The loading of H2SO4 or H3PO4 at an amount equal to or slightly less than that of metals inherent in the wood, having catalysis for promoting the formation of valueless light oxygenates from carbohydrates, was effective for passivating those metals and drastically improving the anhydrosugar yield in torrefaction at 300–320 °C. The total yield of anhydrosugars from wood and the yield of levoglucosan, a dominant anhydrosugar, from cellulose in the wood reached 12.1 and 25.3 wt %, respectively. It was noteworthy that torrefaction altered the composition of components in wood and positively influenced the strength of coke prepared by pelletization and carbonization. In particular, torrefaction in the presence of H2SO4 led to a remarkable densification of pellets during carbonization. The resulting coke had a strength (tensile strength) of up to 24.2 MPa, which was much higher than that of coke directly pelletized and carbonized from wood (9.0 MPa). Moreover, the lignin-enriched torrefied wood selectively produced phenols and combustible gas with H2 as the major component in the carbonization. Under the most optimal conditions examined in this work, 45.7 wt % of the wood was converted into the desired products with the remainder being water and heavy condensable volatiles, while the yield of light oxygenates was greatly reduced.

Atomically Dispersed Metals on Nanodiamond-Derived Hybrid Materials for Heterogeneous Catalysis: Fei Huang, Mi Peng, Hongyang Liu, and Ding Ma;  Acc. Mater. Res. 2023, 4, 3, 223–236 (https://doi.org/10.1021/accountsmr.2c00152)

Abstract

Supported metal catalyst, has been one of the most important systems in the field of heterogeneous catalysis. The great complexity of both the compositions and structures of such supported metal catalysts provides a great degree of freedom for tuning their catalytic properties, which has essentially triggered the explosive growth in research on design and control active metals’ surface structures for decades. An ideal metal catalyst theoretically features maximum active sites and optimal intrinsic reactivity to facilitate a desired chemical reaction. Inspired by the catalytic concepts brought by natural enzymes and homogeneous catalysis, the fabrication of heterogeneous catalysts with atomically dispersed metal atoms has attracted much attention and been extensively explored in recent years. Atomically dispersed metal catalysts (ADMCs) including single-atom catalyst (SACs) and fully exposed cluster catalyst (FECCs), as shining stars in heterogeneous catalysts have recently drawn much attention. The advantages of ADMCs mainly include the following three aspects: (1) the fully exposed active metal atoms can realize the utmost atomic utilization efficiency and reduce the cost of catalysts; (2) the geometric and electronic structure can be effectively regulated by altering the coordination environments of metal atoms and then further tuning the catalytic performance in terms of activity, selectivity, and stability; (3) the precisely designed structures provide a promising platform for digging the structure–performance relationships of active sites with the assistance of theoretical calculations. Owing to these advantages, ADMCs have been used in thermal-catalysis, electrocatalysis, photocatalysis, etc. until now. In this Account, a summary of recent progress regarding ADMCs for heterogeneous thermal catalysis in our group will be presented from the following aspects. First, an overview of great opportunities brought by nanodiamond and its derivatives as substrates for anchoring atomically dispersed metals (ADMs) and tailoring their structures. Next, our recent progress in achieving desirable catalytic performance, including activity, selectivity, and stability over nanodiamond–graphene (ND@G) supported ADMCs will be introduced in detail. Finally, a brief outlook regarding the development directions for ADMCs by discussing current challenges and opportunities will be proposed. It is hoped that this Account can inspire the development of the rational design and various application of ADMCs.

Ruthenium Metal–Organic Frameworks as Stable Nanostructures for Selective Hydrogen Production from Acetaldehyde and Water under Mild Conditions: Yangbin Shen, Chunmei Zhang, Feng Du, Ting Zhang, Yulu Zhan, Hao Tian, and Chang Ming Li; ACS Appl. Nano Mater. 2023, 6, 5, 3750–3757 (https://doi.org/10.1021/acsanm.2c05460)

Abstract

Hydrogen is a promising energy carrier because it is a wide and sustainable source. However, it is still extremely difficult to store and transport hydrogen safely because of its active chemical properties and harsh explosion limits. Organic liquid is a popular research field for hydrogen production and storage. Inspired by its biological metabolism, here acetaldehyde is innovatively used for hydrogen production. The hydrogen content of an acetaldehyde–water solution is 10.2 wt %, which is slightly lower than that of a methanol–water solution but much higher than that of formic acid and formaldehyde. For the first time, we prepared several ruthenium metal–organic frameworks (MOFs) as stable nanostructures for selective hydrogen production from acetaldehyde and water under mild conditions (∼60 °C). Ru-MOFs all have nanoscale pores, and the turnover frequency of ruthenium 2,3,5,6-tetramethyl-1,4-phenylenediamine for acetaldehyde decomposition is up to 223 h–1 in water at 90 °C. Because C–C bond cleavage is an inevitable step for hydrogen or energy production from C2 organics, ion chromatography, high-performance liquid chromatography, 1H NMR spectroscopy, and mass spectrometry were employed to propose a catalytic process of hydrogen production from acetaldehyde decomposition. We evidently prove that water participates in acetaldehyde decomposition, thereby claiming an acetaldehyde–water reforming process. Additionally, we confirm that formic acid and acetic acid are the intermediates during the hydrogen production process. This research not only holds great promise for hydrogen production from C2 organics at low temperatures, as well as catalytic technology for C–C bond cleavage, but it also provides certain profound scientific insights for hydrogen or energy production from multicarbon organics, such as biomass.

Highly Cross-Linked 3D ε-Fe2O3 Networks Organized by Ultrathin Nanosheets as High-Performance Anode Materials for Lithium-Ion Storage: Deli Li, Jun Liang, Shuang Song, and Li Li; ACS Appl. Nano Mater. 2023, 6, 4, 2356–2365 (https://doi.org/10.1021/acsanm.2c04359)

Abstract

The rational design and engineering of three-dimensional (3D) micro-/nano-architectures still remains a technological challenge for electrochemical energy storage materials. In the current work, a facile and scalable structural engineering strategy is described for the synthesis of highly cross-linked 3D ε-Fe2O3 networks via an in situ manipulation of the molecular framework-engaged reactions. The as-obtained ε-Fe2O3 with a large specific surface area and abundant mesopores possesses a 3D interlocked architecture organized by ultrathin nanosheets. The formation mechanism of this unique structure is explored, which is shown to be Fe(CN)64–-mediated molecular-level template action leading to the self-assembly of a 3D framework. As a conversion-type anode for LIBs, the optimized ε-Fe2O3 networks exhibit a high reversible specific capacity, good rate capability, as well as long-term stability, with a reversible capacity of 953.8 mAh g–1 that is retained beyond 600 cycles at 1.0 A g–1. In addition, the excellent Li storage performance can be ascribed to the microarchitectured ε-Fe2O3 networks, which provide multiscale dimensions, mesoporous structure, some oxygen deficiencies, as well as good structural integrity upon prolonged cycling. Furthermore, the experimental results and DFT calculations showed that ε-Fe2O3 was able to form a key Li5Fe5O8–x  phase during the lithiation/delithiation process, in which the structural properties of ε-Fe2O3 inherently favor the intercalation of Li ions within ε-Fe+2O3, thus leading to the experimentally observed high performance rates.

Bifunctional Electrocatalyst for Rechargeable Zn–Air Batteries: Xiangyi Li, Yijiang Liu, Jikai Wen, Baoyu Qing, Mei Yang, Bei Liu, Hongbiao Chen, and Huaming Li;  ACS Appl. Nano Mater. 2023, 6, 4, 2719–2728 (https://doi.org/10.1021/acsanm.2c05107)

Abstract

The exploration of highly efficient, low-cost, and durable oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional electrocatalysts is extremely desirable but challenging for the practical application of Zn–air batteries. Herein, we report the fabrication of a FeNi alloy nanoparticle (NP)-decorated N,S dual-doped carbon nanocomposite (denoted FeNi/NS-C) as a bifunctional electrocatalyst for Zn–air batteries. The FeNi/NS-C electrocatalyst is produced through the complexation of a N-rich imidazolyl-phenanthroline derivative with metal salts, followed by pyrolysis in the presence of trithiocyanuric acid (TTCA). The FeNi/NS-C electrocatalyst shows comparable ORR activity to that of Pt/C (E1/2 = 0.83 V) and superior OER activity to that of IrO2 (Ej=10 = 1.585 V). The liquid- and solid-state Zn–air batteries assembled with the FeNi/NS-C exhibit high power density and specific capacity. In particular, the FeNi/NS-C-based Zn–air batteries display remarkable durability over 1000 h at 5 mA cm–2 and 70 h at 2 mA cm–2 in liquid and solid electrolytes, respectively. The high performance of the FeNi/NS-C may be related to the synergistic effect of the bimetallic alloy NPs and the N,S dual-doped carbon matrix with a high surface area, porous structure, and unique hybridized morphology.

Nanometer-thin ZrO2 Coating for NiO on MWCNTs as Anode for Improved Performance of Sodium-Ion Batteries: Fazal Subhan, Ata-ur Rehman, Norah Alwadai, Maryam Al Huwayz, Beriham Ibrahim Basha, Karma Albalawi, Violeta Jevtovic, Abdulaziz A. Alanazi, Hamza S. Al-Shehri, and Syed Mustansar  Abbas;  ACS Appl. Nano Mater. 2023, 6, 4, 2507–2516 (https://doi.org/10.1021/acsanm.2c04860)

Abstract

A very simple coprecipitation approach is adopted to prepare ZrO2-coated NiO on MWCNTs nanocomposites with NiO nanoparticles within 10–15 nm size. The XPS studies confirm the presence of Zr, Ni, C, and O elements in the sample, while the BET and BJH analyses reveal a typical surface area of 204.44 m2 g–1 with pores between 10 and 15 nm. The electrochemical performance studies of the ZrO2-coated nanocomposite electrode show a higher charge/discharge capacity of 688.3/688.7 mAh g–1 after 200 cycles with excellent retention capacity (96%) and cycling stability. A minor capacity fading has been observed in the rate performance of the electrodes at currents ranging from 100 to 5000 mA g–1. It also reveals that coin cells tend to maintain their maximum Coulombic efficiency of 99.9% at a low current density, revealing a notable reversible capacity. Therefore, adding MWCNTs significantly increases electrochemical performance and prevents pulverization of active materials. While structural flexibility helps in mitigating the volumetric expansion. During the cycling process, the ZrO2 coating helps improve structural stability and facilitate the diffusion of Na ions.

Ferromagnetism of Nanometer Thick Sputtered Fe3GeTe2 Films in the Absence of Two-Dimensional Crystalline Order: Implications for Spintronics Applications: Qianwen Zhao, ChaoChao Xia, Hanying Zhang, Baiqing Jiang, Tunan Xie, Kaihua Lou, and Chong Bi; ACS Appl. Nano Mater. 2023, 6, 4, 2873–2882 (https://doi.org/10.1021/acsanm.2c05213)

Abstract

The discovery of ferromagnetism in two-dimensional (2D) monolayers has stimulated growing research interest in both spintronics and material science. However, these 2D ferromagnetic layers are mainly prepared through an incompatible approach for large-scale fabrication and integration, and moreover, a fundamental question of whether the observed ferromagnetism actually correlates with the 2D crystalline order has not been explored. Here, we choose a typical 2D ferromagnetic material, Fe3GeTe2, to address these two issues by investigating its ferromagnetism in an amorphous state. We have fabricated nanometer thick amorphous Fe3GeTe2 films approaching the monolayer thickness limit of crystallized Fe3GeTe2 (0.8 nm) through magnetron sputtering. Compared to crystallized Fe3GeTe2, we found that the basic ferromagnetic attributes, such as the Curie temperature which directly reflects magnetic exchange interactions and local anisotropic energy, do not change significantly in the amorphous states. This is attributed to the short-range atomic order, as confirmed by valence state analysis, being almost the same for both phases. The persistence of ferromagnetism in the ultrathin amorphous counterpart has also been confirmed through magnetoresistance measurements, where two unconventional switching dips arising from electrical transport within domain walls are clearly observed in the amorphous Fe3GeTe2 single layer. These results indicate that the long-range ferromagnetic order of crystallized Fe3GeTe2 may not correlate to the 2D crystalline order, and the corresponding ferromagnetic attributes can be utilized in an amorphous state which suits large-scale fabrication in a semiconductor technology-compatible manner for spintronics applications.

Origin of Ferromagnetic Exchange Coupling in Donor–Acceptor Biradical Analogues of Charge-Separated Excited States: Ju Chen, Jing Yang, Munendra Yadav, David A. Shultz, and Martin L. Kirk; Inorg. Chem. 2023, 62, 2, 739–747 (https://doi.org/10.1021/acs.inorgchem.2c02903)

Abstract

A new donor–acceptor biradical complex, TpCum,MeZn(SQ-VD) (TpCum,MeZn = zinc(II) hydro-tris(3-cumenyl-5-methylpyrazolyl)borate complex cation; SQ = orthosemiquinone; VD = oxoverdazyl), which is a ground-state analogue of a charge-separated excited state, has been synthesized and structurally characterized. The magnetic exchange interaction between the S = 1/2 SQ and the S = 1/2 VD within the SQ-VD biradical ligand is observed to be ferromagnetic, with J+SQ-VD = +77 cm–1 (H = −2JSQ-VDŜSQ·ŜVD) determined from an analysis of the variable-temperature magnetic susceptibility data. The pairwise biradical exchange interaction in TpCum,MeZn(SQ-VD) can be compared with that of the related donor–acceptor biradical complex TpCum,MeZn(SQ-NN) (NN = nitronyl nitroxide, S = 1/2), where JSQ-NN ≅ +550 cm–1. This represents a dramatic reduction in the biradical exchange by a factor of ∼7, despite the isolobal nature of the VD and NN acceptor radical SOMOs. Computations assessing the magnitude of the exchange were performed using a broken-symmetry density functional theory (DFT) approach. These computations are in good agreement with those computed at the CASSCF NEVPT2 level, which also reveals an S = 1 triplet ground state as observed in the magnetic susceptibility measurements. A combination of electronic absorption spectroscopy and CASSCF computations has been used to elucidate the electronic origin of the large difference in the magnitude of the biradical exchange coupling between TpCum,MeZn(SQ-VD) and TpCum,MeZn(SQ-NN). A Valence Bond Configuration Interaction (VBCI) model was previously employed to highlight the importance of mixing an SQSOMO → NNLUMO charge transfer configuration into the electronic ground state to facilitate the stabilization of the high-spin triplet (S = 1) ground state in TpCum,MeZn(SQ-NN). Here, CASSCF computations confirm the importance of mixing the pendant radical (e.g., VD, NN) LUMO (VDLUMO and NNLUMO) with the SOMO of the SQ radical (SQSOMO) for stabilizing the triplet, in addition to spin polarization and charge transfer contributions to the exchange. An important electronic structure difference between TpCum,MeZn(SQ-VD) and TpCum,MeZn(SQ-NN), which leads to their different exchange couplings, is the reduced admixture of excited states that promote ferromagnetic exchange into the TpCum,MeZn(SQ-VD) ground state, and the intrinsically weaker mixing between the VDLUMO and the SQSOMO compared to that observed for TpCum,MeZn(SQ-NN), where this orbital mixing is significant. The results of this comparative study contribute to a greater understanding of biradical exchange interactions, which are important to our understanding of excited-state singlet–triplet energy gaps, electron delocalization, and the generation of electron spin polarization in both the ground and excited states of (bpy)Pt(CAT-radical) complexes.

Zn3Sb4O6F6 and KI-Doped Zn3Sb4O6F6: A Metal Oxyfluoride System for Photocatalytic Activity, Knoevenagel Condensation, and Bacterial Disinfection : Sayantani Paul, Bibaswan Sen, Nilendu Basak, Nirman Chakraborty, Kiron Bhakat, Sangita Das, Ekramul Islam, Swastik Mondal, Sk Jahir Abbas, and Sk Imran Ali;  Inorg. Chem. 2023, 62, 2, 1032–1046 (https://doi.org/10.1021/acs.inorgchem.2c04006)

Abstract

Zn3Sb4O6F6 crystallites were synthesized by a pH-regulated hydrothermal synthetic approach, while doping on Zn3Sb4O6F6 by KI was performed by the “incipient wetness impregnation technique.” The effect of KI in Zn3Sb4O6F6 is found with the changes in morphology in the doped compound, i.e., needle-shaped particles with respect to the irregular cuboid and granular shaped in the pure compound. Closer inspection of the powder diffraction pattern of doped compounds also reveals the shifting of Braggs’ peaks toward a lower angle and the difference in cell parameters compared to the pure compound. Both metal oxyfluoride comprising lone pair elements and their doped compounds have been successfully applied as photocatalysts for methylene blue dye degradation. Knoevenagel condensation reactions were performed using Zn3Sb4O6F6 as the catalyst and confirmed 99% yield even at 60 °C temperature under solvent-free conditions. Both pure and KI-doped compounds were tested against several standard bacterial strains, i.e., Enterobacter sp., Escherichia coli, Staphylococcus sp., Salmonella sp., Bacillus sp., Proteous sp., Pseudomonas sp., and Klebsiella sp. by the “disk diffusion method” and their antimicrobial activities were confirmed.

Emergent Transitions: Discord between Electronic and Chemical Pressure Effects in the REAl3 (RE = Sc, Y, Lanthanides) Series : Amber Lim, Katerina P. Hilleke, and Daniel C. Fredrickson;   Inorg. Chem. 2023, 62, 11, 4405–4416 (https://doi.org/10.1021/acs.inorgchem.2c03393)

Abstract

Atomic packing and electronic structure are key factors underlying the crystal structures adopted by solid-state compounds. In cases where these factors conflict, structural complexity often arises. Such is born in the series of REAl3 (RE = Sc, Y, lanthanides), which adopt structures with varied stacking patterns of face-centered cubic close packed (FCC, AuCu3 type) and hexagonal close packed (HCP, Ni3Sn type) layers. The percentage of the hexagonal stacking in the structures is correlated with the size of the rare earth atom, but the mechanism by which changes in atomic size drive these large-scale shifts is unclear. In this Article, we reveal this mechanism through DFT-Chemical Pressure (CP) and reversed approximation Molecular Orbital (raMO) analyses. CP analysis illustrates that the Ni3Sn structure type is preferable from the viewpoint of atomic packing as it offers relief to packing issues in the AuCu3 type by consolidating Al octahedra into columns, which shortens Al–Al contacts while simultaneously expanding the RE atom’s coordination environment. On the other hand, the AuCu3 type offers more electronic stability with an 18-n closed-shell configuration that is not available in the Ni3Sn type (due to electron transfer from the RE dz2 atomic orbitals into Al-based states). Based on these results, we then turn to a schematic analysis of how the energetic contributions from atomic packing and the electronic structure vary as a function of the ratio of FCC and HCP stacking configurations within the structure and the RE atomic radius. The minima on the atomic packing and electronic surfaces are non-overlapping, creating frustration. However, when their contributions are added, new minima can emerge from their combination for specific RE radii representing intergrowth structures in the REAl3 series. Based on this picture, we propose the concept of emergent transitions, within the framework of the Frustrated and Allowed Structural Transitions principle, for tracing the connection between competing energetic factors and complexity in intermetallic structures.

Electrocatalytic NO Reduction to NH3 on Mo2C Nanosheets : Kai Chen, Peng Shen, Nana Zhang, Dongwei Ma, and Ke Chu;  Inorg. Chem. 2023, 62, 2, 653–658 (https://doi.org/10.1021/acs.inorgchem.2c03714)

Abstract

Electrocatalytic reduction of NO to NH3 (NORR) emerges as a promising route for achieving harmful NO treatment and sustainable NH3 generation. In this work, we first report that Mo2C is an active and selective NORR catalyst. The developed Mo2C nanosheets deliver a high NH3 yield rate of 122.7 μmol h–1 cm–2 with an NH3 Faradaic efficiency of 86.3% at −0.4 V. Theoretical computations unveil that the surface-terminated Mo atoms on Mo2C can effectively activate NO, promote protonation energetics, and suppress proton adsorption, resulting in high NORR activity and selectivity of Mo2C.

One Bridge, Three Bonds: A Frontier in Multiple Bonding in Heterobimetallic Complexes: Nathanael H. Hunter, Nathanael H. Hunter, Jeremiah E. Stevens, Curtis E. Moore, and Christine M. Thomas;  Inorg. Chem. 2023, 62, 2, 659–663 (https://doi.org/10.1021/acs.inorgchem.2c03716)

Abstract

A single bridging phosphinoamide ligand was shown to support a metal–metal triple bond in a Zr/Co heterobimetallic complex. The similarity of the bonding in this compound to previously synthesized Zr/Co species, and therefore the assignment of the Zr/Co triple bond, is supported by the structural parameters of the complex, the electronic structure predicted by density functional theory, and complete-active-space self-consistent-field (CASSCF) calculations. This demonstrates that metal–metal multiple bonds can be realized in heterobimetallic complexes without multiple bridging ligands to enforce the proximity of the two metals.

Screening out the Transition Metal Single Atom Supported on Onion-like Carbon (OLC) for the Hydrogen Evolution Reaction: Jiguang Du, Jun Chen, Chuanyu Zhang, and Gang Jiang;  Inorg. Chem. 2023, 62, 2, 1001–1006 (https://doi.org/10.1021/acs.inorgchem.2c03922)

Abstract

A recent experiment has confirmed that onion-like nanospheres of carbon (OLC) covered with single Pt atoms show comparable hydrogen evolution reaction (HER) catalytic activity to the commercial Pt/C. In this work, we have performed screening calculations on the single transition metal (TM) atom supported on OLC (a total of 26 candidates) using the density functional theory (DFT) to find excellent HER catalysts. Our calculated results indicate that the Nb1/CLO, Mo1/CLO, Ru1/CLO, Rh1/CLO, Pd1/CLO, and Ir1/OLC show high-efficient catalysts performance for the HER, as experimental Pt1/OLC does. We also try to seek an appropriate descriptor relevant to the Gibbs free energies, and the average local ionization energy (ALIE), which is first used to predict HER activity, shows a perfect linear correlation with Gibbs free energy. It is interesting to note that the ALIE descriptor is more successful than the commonly used d-band center.

Green Phosphate Route of Regeneration of LiFePO4 Composite Materials from Spent Lithium-Ion Batteries: Zixuan Wang, Dandan Wu, Xi Wang, Ye Huang, and Xu Wu;  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.

Enhanced Weathering and Corrosion Resistance of Eu-Doped ZnO Solid Solution Material by Fluorescence Modification: Si-Rui Zhao, Zi-Xiang Liu, Jin-Ku Liu, Jichang Liu, Bo Luan, Yun-Sheng Ma, and Peng-Peng Liu;  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.

Kinetics, Mechanism, and Optimization Modeling of a Green LFP Delithiation Process Developed for Direct Recycling of Lithium-Ion Batteries: François Larouche, Frédéric Voisard, Kamyab Amouzegar, Georges Houlachi, Patrick Bouchard, Ashok Vijh, and George P. Demopoulos;  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.

Effect of Fe3+ and/or PO43– Doping on the Electrochemical Performance of LiNi0.5Mn1.5O4 Cathode Material for Li-Ion Batteries: Shaoxiong Fu, Yuan Zhang, Yuhan Bian, Jiahao Xu, Li Wang, and Guangchuan Liang; 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.

Dual Modification of Olivine LiFe0.5Mn0.5PO4 Cathodes with Accelerated Kinetics for High-Rate Lithium-Ion Batteries: Hongbo Jin, Jiahao Zhang, Li Qin, Yanjie Hu, Hao Jiang, and Chunzhong Li;  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.