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Transition metal sulfides as anode materials for sodium‐ion batteries (SIBs) have the advantage of high capacity. However, their cycle‐life and rate performance at ultra‐high current density is still a thorny issue that limit the applicability of these materials. In this paper, the carbon‐embedded heterojunction with sulfur‐vacancies regulated by ultrafine bimetallic sulfides (vacancy‐CoS2/FeS2@C) with robust interfacial C‐S‐Co/Fe chemical bonds is successfully synthesized and explored as an anode material for sodium‐ion battery. By changing the ratio of two metal cations, the concentration of anion sulfur vacancies can be in‐situ adjusted without additional post‐treatment. The as‐prepared vacancy‐CoS2/FeS2@C anode material offers ultrahigh rate performance (285.1 mAh g−1 at 200 A g−1), and excellent long‐cycle stability (389.2 mAh g−1 at 40 A g−1 after 10000 cycles), outperforming all reported transition metal sulfides‐based anode materials for SIBs. Both in‐situ and ex‐situ characterizations provide strong evidence for the evolution mechanism of the phases and stable solid‐electrolyte interface (SEI) on the vacancy‐CoS2/FeS2@C surface. The density functional theory calculations show that constructing heterojunction with reasonable concentration of vacancies can significantly increase the anode electronic conductivity. Notably, the assembled vacancy‐CoS2/FeS2@C//Na3V2(PO4)3/C full‐cell shows a capacity of 226.2 mAh g−1 after 400 cycles at 2.0 A g−1, confirming this material's practicability. [ABSTRACT FROM AUTHOR]

VS4 has a unique layered atomic chain structure and has the potential to become a high-performance cathode material of magnesium-ion batteries with a high capacity and long cycle life. However, low conductivity and sluggish Mg2+ diffusivity during cycling limit its practical application in large-scale energy storage. Herein, a cooperative assembly-directed strategy is adopted to synthesize VS4 nanorods grown in situ on carbon nanotubes (CNTs/VS4). VS4 nanorods are tightly anchored to CNTs through V–O–C interface covalent bonds, and CNTs can enhance the electronic conductivity of the nanocomposite. In addition, the ion insertion reaction using Mg2+ and MgCl+ as carriers reduces the polar barrier for divalent Mg2+ ion transport. This rationally designed architecture promotes ion diffusion and electron transfer, thus facilitating reaction kinetics. The cooperative assembly-oriented strategy can endow CNTs/VS4 with excellent magnesium storage properties, including a high reversible capacity of 223.2 mAh g−1 at a current density of 50 mA g−1, a remarkable discharge capacity of 91.8 mAh g−1 even at 2,000 mA g−1, and an impressive capacity retention of 85.2% after 1,000 cycles at 500 mA g−1. Moreover, this strategy can serve as a general synthetic method for the complexation of VS4 with other carbon nanostructures. [ABSTRACT FROM AUTHOR]

Electrodeposition, a binder-free technique, enables the formation of uniform and well-defined structures on the electrode surface. Herein, the material has directly grown on nickel foam by deposition through cyclic voltammetry at a fixed scan rate. The surface morphology of as-synthesized electrodes is observed with SEM and the electrochemical examination has been performed in three-electrode assembly. The highest specific capacitance attained from GCD analysis for MnS is 1453 F/g, CoS has 2476 F/g and CuS exhibits 1908 F/g at 6 A/g current density. The quantitative investigation of the inherent charge storage mechanism of an individual electrode is achieved by implementing different mathematical models on experimental data sets. The electrodes displayed a more diffusive contribution which uncovered our findings that each electrode illustrates the battery-grade properties. The results suggested that the fabricated electrode consumes an excellent potential as a high energy source for hybrid energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical core-shelled CoMo-LDH@CuCo 2 S 4 NWAs/NF is prepared by hydrothermal synthesis and electrodeposition. • The electrode exhibits a high specific capacity of 1265.9 C g−1 at 1 A g−1. • The electrode shows a 92.2% capacity retention ratio at 10 A g−1 after 10, 000 cycles. • The energy density of the assembled HSC device is 52.2 Wh kg−1 at the power density of 983.9 W kg−1. The development of core-shelled heterostructures with the unique morphology can improve the electrochemical properties of hybrid supercapacitors (HSC). Here, CuCo 2 S 4 nanowire arrays (NWAs) are vertically grown on nickel foam (NF) utilizing hydrothermal synthesis. Then, CoMo-LDH nanosheets are uniformly deposited on the CuCo 2 S 4 NWAs by electrodeposition to obtain the CoMo-LDH@CuCo 2 S 4 NWAs/NF electrode. Due to the superior conductivity of CuCo 2 S 4 (core) and good redox activity of CoMo-LDH (shell), the electrode shows excellent electrochemical properties. The electrode's specific capacity is 1271.4 C g−1 at 1 A g−1, and after 10, 000 cycles, its capacity retention ratio is 92.2 % at 10 A g−1. At a power density of 983.9 W kg−1, the CoMo-LDH@CuCo 2 S 4 NWAs/NF//AC/NF device has an energy density of 52.2 Wh kg−1. This indicates that CoMo-LDH@CuCo 2 S 4 /NF has a great potential for supercapacitors. [ABSTRACT FROM AUTHOR]

Abstract Electrochemical CO2 reduction (ECR) to value-added products is regarded as a sustainable strategy to mitigate global warming and energy crisis, and designing highly efficient and robust catalysts is essential. In this work, transition metal sulfides (TMS)-decorated CuS microflower-like structures were prepared via the one-pot hydrothermal synthesis method for ECR to CO, and the influence of TMS doping on ECR performance was demonstrated. Characterization of the catalysts was performed using XRD, FESEM-EDS, N2 physisorption, and XPS, revealing the successful loading of TMS, the formation of microflower-like architectures and the generation of sulfur vacancies. Electrochemical tests demonstrated that doping ZnS, Bi2S3, CdS and MoS2 improved the intrinsic CO2 reduction activity of the CuS catalyst. Particularly, the MoS2-CuS composite catalyst with imperfect petal-like structure showed uniform distribution of edge Mo sites, which worked synergistically with the formed grain boundaries (GBs) and undercoordinated S vacancy sites in promoting CO2 activation, stabilizing *COOH adsorption, facilitating *CO desorption, and lowering the energy barrier of the potential-limiting step for improved CO selectivity. The MoS2-CuS catalyst achieved a maximum CO selectivity of 83.2% at –0.6 V versus the reversible hydrogen electrode (RHE) and a high CO cathodic energetic efficiency of 100%. At this potential, the catalyst maintained stable catalytic activity and CO selectivity during a 333-min electrolysis process. The findings will offer a promising avenue for the development of efficient and stable catalysts for CO production from ECR.

Electrochemical CO2 reduction (ECR) to value-added products is regarded as a sustainable strategy to mitigate global warming and energy crisis, and designing highly efficient and robust catalysts is essential. In this work, transition metal sulfides (TMS)-decorated CuS microflower-like structures were prepared via the one-pot hydrothermal synthesis method for ECR to CO, and the influence of TMS doping on ECR performance was demonstrated. Characterization of the catalysts was performed using XRD, FESEM-EDS, N2 physisorption, and XPS, revealing the successful loading of TMS, the formation of microflower-like architectures and the generation of sulfur vacancies. Electrochemical tests demonstrated that doping ZnS, Bi2S3, CdS and MoS2 improved the intrinsic CO2 reduction activity of the CuS catalyst. Particularly, the MoS2-CuS composite catalyst with imperfect petal-like structure showed uniform distribution of edge Mo sites, which worked synergistically with the formed grain boundaries (GBs) and undercoordinated S vacancy sites in promoting CO2 activation, stabilizing *COOH adsorption, facilitating *CO desorption, and lowering the energy barrier of the potential-limiting step for improved CO selectivity. The MoS2-CuS catalyst achieved a maximum CO selectivity of 83.2% at –0.6 V versus the reversible hydrogen electrode (RHE) and a high CO cathodic energetic efficiency of 100%. At this potential, the catalyst maintained stable catalytic activity and CO selectivity during a 333-min electrolysis process. The findings will offer a promising avenue for the development of efficient and stable catalysts for CO production from ECR. [ABSTRACT FROM AUTHOR]

Supercapattery is an ideal energy storage device combining the features of supercapacitors and batteries, offers a high‐energy density as well as high‐power density with extended operational lifespan. In this work, zinc sulfide (ZnS) and zinc sulfide/nickel oxide (ZnS/NiO) nanocomposite was synthesized via chemical coprecipitation method and characterized using state‐of‐the‐art analytical tools. The ZnS/NiO electrode exhibited remarkable electrochemical performance as an electrode material than pure ZnS. The ZnS/NiO nanocomposite exhibited high crystallinity, and spherical nanoparticles with an average grain size of 20–40 nm having a homogeneous dispersion. The ZnS/NiO electrode exhibited an ultrahigh specific capacity of 1803.87 Cg−1 at a relatively low scan rate of 10 mVs−1 in a 1 M KOH solution from cyclic voltammetry and 393 Cg−1 at 16 Ag−1 from charge discharge measurements, and it showed exceptional cycling stability (98 % capacity retention after 1000 cycles). Furthermore, the ZnS/NiO symmetric supercapattery device exhibited 44.43 Fg−1 specific capacitance, 5.52 Wh kg−1 energy density, and 1600 Wkg−1 power density at current density of 0.8 Ag−1 in 1 M KOH solution from galvanostatic charge discharge. After 3000 cycles, the ZnS/NiO nanomaterial demonstrated promising cyclic stability of 95 %. The ZnS/NiO supercapattery nanocomposite might be considered as a potential hybrid electrode material for the future development of electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

Developing a reasonable design of a lithiophilic artificial solid electrolyte interphase (SEI) to induce the uniform deposition of Li+ ions and improve the Coulombic efficiency and energy density of batteries is a key task for the development of high-performance lithium metal anodes. Herein, a high-performance separator for lithium metal anodes was designed by the in situ growth of a metal–organic framework (MOF)-derived transition metal sulfide array as an artificial SEI on polypropylene separators (denoted as Co9S8-PP). The high ionic conductivity and excellent morphology provided a convenient transport path and fast charge transfer kinetics for lithium ions. The experimental data illustrate that, compared with commercial polypropylene separators, the Li//Cu half-cell with a Co9S8-PP separator can be cycled stably for 2000 h at 1 mA cm−2 and 1 mAh cm−2. Meanwhile, a Li//LiFePO4 full cell with a Co9S8-PP separator exhibits ultra-long cycle stability at 0.2 C with an initial capacity of 148 mAh g−1 and maintains 74% capacity after 1000 cycles. This work provides some new strategies for using transition metal sulfides to induce the uniform deposition of lithium ions to create high-performance lithium metal batteries. [ABSTRACT FROM AUTHOR]

Coral-clustered CoNi 5 S 8 -Ni 2 P-FeP 2 three-phase heterostructure, which is anchored on nickel foam surface by a two-step gas-phase sulfurization/phosphorization strategy as free-standing multifunctional electrocatalysts, exhibits excellent HER/OER/UOR properties and shows great potential in water electrolysis applications. [Display omitted] Rational designing efficient transition metal-based multifunctional electrocatalysts is highly desirable for improving the efficiency of hydrogen production from water cracking. Herein, a self-supported three-phase heterostructure electrocatalyst of nickel–cobalt sulfide/nickel phosphide/iron phosphide (CoNi 5 S 8 -Ni 2 P-FeP 2) was prepared by a two-step gas-phase sulfurization/phosphorization strategy. The heterostructure in CoNi 5 S 8 -Ni 2 P-FeP 2 provides a favorable interfacial environment for electron transfer and synergistic interaction of multiphase active components, while the introduced electronegative P/S not only serves as a carrier for proton capture in the hydrogen evolution reaction (HER) process but also promotes the metal-electron outflow, which in turn accelerates the generation of high-valent Ni3+ species to enhance the catalytic activity of oxygen evolution reaction (OER) and urea oxidation reaction (UOR). As expected, CoNi 5 S 8 -Ni 2 P-FeP 2 reveals excellent multifunctional electrocatalytic properties. An overpotential of 35/215 mV is required to reach 10 mA cm−2 for HER/OER. More encouragingly, a current of 100 mA cm−2 requires only 1.36 V for UOR with CoNi 5 S 8 -Ni 2 P-FeP 2 as anode, which is much lower as compared to the OER (1.50 V). Besides, a two-electrode water/urea electrolyzer assembled based on CoNi 5 S 8 -Ni 2 P-FeP 2 has a voltage of only 1.59/1.48 V when the system reaches 50 mA cm−2. This work provides a new idea for the design of energy-efficient water/urea-assisted water-splitting multifunctional catalysts with multi-component heterostructure synergistic interface engineering. [ABSTRACT FROM AUTHOR]

It is of great significance to use biomass resources to prepare electrocatalysts for hydrogen evolution reaction (HER) during water splitting. Herein, using egg white as S source (adding Na2MoO4 only), we fabricate amorphous N/P-doped molybdenum oxygen sulfide grown on Ni foam (NF) via a facile one-pot hydrothermal method. N and P elements in egg white can be partially doped into MoOxSy to produce the electrocatalyst used for HER. Under different reaction temperature of m °C (m = 160, 170, 180) and mole number of n (n = 6, 10, 12 mmol) of the Mo salt (Na2MoO4) added, series of N/P-MoOxSy/NF-m–n materials are obtained. The loose and porous morphology of the MoOxSy/NF-m–n is conducive to full contact with the electrolyte, and N/P doping can optimize the electronic structure, together improving the HER performance. The optimized electrocatalyst of N/P-MoOxSy/NF-170–10 (m = 170, n = 10) shows the best HER activity and stability, requiring a much low overpotential of 122 mV to achieve the current density of 10 mA cm−2 (η10 = 122 mV), and operating long-term (≥ 40 h) electrolysis at a constant potential of − 130 mV (vs. RHE) in acidic media (0.5 M H2SO4). The electrocatalytic property is comparable to or even beyond the known HER electrocatalysts derived from biomass. This work provides a new strategy for the design of non-metal-doped catalysts using biomass as raw materials. [ABSTRACT FROM AUTHOR]

Transition metal sulfides (TMS) exhibit significant promise as non‐noble‐metal electrocatalysts for the oxygen evolution reaction (OER) in alkaline environments, notwithstanding their susceptibility to long‐term instability due to the gradual leaching of surface‐reconstructed sulfate ions (SO42−). In this study, a sulfate ion‐assisted strategy is proposed to stabilize the surface‐reconstructed SO42− of FeNiS2. The findings reveal that SO42− experiences considerable loss in KOH due to the infinite concentration gradient of SO42− on the surface. Conversely, in K2SO4/KOH, this strategy mitigates rapid leaching and preserves the predominant surface‐reconstructed SO42−, thereby enhancing stability in both accelerated degradation (5000 cycles) and long‐term (≥120 h) tests, with ≈95% current density retained. Furthermore, the optimal concentration of SO42− proves to be crucial, as supported by both experimental and theoretical results. This approach offers insights into bolstering the long‐term OER stability of TMS and similar compounds, thereby advancing the prospects for widespread application in electrocatalytic water splitting. [ABSTRACT FROM AUTHOR]

Amino acids are one of the most important building blocks of life. During the biochemical process of translation, cells sequentially connect amino acids via amide bonds to synthesize proteins, using the genetic information in messenger RNA (mRNA) as a template. From a prebiotic perspective (i.e., without enzymatic catalysis), joining amino acids to peptides via amide bonds is difficult due to the highly endergonic nature of the condensation reaction. We show here that amides can be formed in reactions catalyzed by the transition metal sulfides from acetylene, carbon monoxide and ammonia under aqueous conditions. Some α- and β-amino acids were also formed under the same conditions, demonstrating an alternative cyanide-free path for the formation of amino acids in prebiotic environments. Experiments performed with stable isotope labeled precursors, like 15NH4Cl and 13C-acetylene, enabled the accurate mass spectroscopic identification of the products formed from the starting materials and their composition. Reactions catalyzed using the transition metal sulfides seem to offer a promising alternative pathway for the formation of amides and amino acids in prebiotic environments, bypassing the challenges posed by the highly endergonic condensation reaction. These findings shed light on the potential mechanisms by which the building blocks of life could have originated on early Earth. [ABSTRACT FROM AUTHOR]

Supercapacitor (SC) devices holds an important position between traditional capacitors and ion batteries in terms of energy density and power density values. In particular, SC′s greater power density values than Li‐ion batteries make them useful for some specific applications, such as storing energy in hybrid cars while the car slows down. Increasing energy density values is one of the key challenges for the SC community. Transition metal dichalcogenides (TMDCs), are one of the new developing important material systems to have this potential, compared to their counterparts' transition metal oxides and conductive polymers. This review is about giving insight into the electrochemical performances of two‐dimensional (2D) layered transition metal sulfides (TMS) such as MoS2, WS2, TaS2, NbS2, VS2, TiS2 and ZrS2 materials. On the other hand, the methods mostly used in synthesizing these materials are presented. [ABSTRACT FROM AUTHOR]

Transition metal sulfides (TMSs) still confront the challenges of capacity fading and inferior fast‐charging capability for sodium storage. The rational design of heterostructures enables a new approach to conquer these drawbacks. In this work, a hierarchical structure consisting of SnS2 nanosheets and FeS2 microrods with triphasic heterostructures is proposed by the facile secondary growth and sulfidation process. The introduction of tin sources regulates the proportion of pyrite and marcasite phases, thereby achieving the triphasic heterostructures comprising pyrite, marcasite FeS2, and SnS2. When served as anode material for sodium‐ion batteries, the optimized sample exhibits a high reversible capacity (901 mAh g−1) and durable cycling performances (827 mAh g−1 after 200 cycles at 1 A g−1 and 742 mAh g−1 after 700 cycles at 5 A g−1). Paring with the commercial Na3V2(PO3)3 cathodes, the full‐cell also delivers extraordinary cyclic stability with a high capacity of 618 mAh g−1 (based on the weight of anode material) after 200 cycles at 1 A g−1 (98.7% capacity retention). The hierarchical structure with adjustably triphasic heterogeneous interfaces alleviates the volumetric expansion and interfacial passivation of active material, while modulating the energy band structure and inducing the build‐in electric fields to boost Na+/electrons transport rate. [ABSTRACT FROM AUTHOR]

The commercialization of Li−S batteries is seriously hindered by polysulfides with severe shuttle effect, and the inherent insulating properties and slow reaction kinetics of insoluble Li2S products. Transition metal sulfides (TMSs) have a high adsorption capacity for polysulfides and have been shown to have a strong catalytic effect on polysulfide conversion reactions. This paper reviews the research on the application of Unary TMSs, heterostructures, etc. in Li−S batteries, and gives some research methods for TMD catalysts in Li−S batteries. Finally, it points out the main focuses and direction of future Li−S battery research and development. It aims to provide some insights into the design and manufacture of advanced Li−S batteries for commercial use. [ABSTRACT FROM AUTHOR]

[Display omitted] • PBA@CCH nanocubes are successfully constructed via an in-situ epitaxial growth strategy. • The morphology and structure of the coating can be modulated by varying the composition of reaction reagents. • The formation mechanism of the coating with variable morphology are discussed and analyzed in detail. • The CoNi2S4/Co9S8@Co4S3 heterogeneous nanocubes are fabricated via one-step carbonization and sulfidation method. Construction of Prussian blue analogues (PBAs) with heterostructure is beneficial to preparing PBAs derivatives with superior electrochemical performance. In this work, the core–shell nanostructured nanocubes composed of nickel hexacyanocobalt PBA (NiCo-PBA)@cobalt carbonate hydroxide (CCH) are synthesized through an in-situ epitaxial growth strategy, and the formation mechanisms of coating are carefully validated and specifically discussed. Then, the precursors are successfully transformed into hierarchical CoNi 2 S 4 /Co 9 S 8 @Co 4 S 3 via the gas-phase vulcanization method. Benefiting from the intriguing heterostructure and multicomponent sulfides, the CoNi 2 S 4 /Co 9 S 8 @Co 4 S 3 -80 electrode exhibits a high specific capacity of 799 ± 16C/g (specific capacitance of 1595 ± 31F/g) at 1 A/g, ultra-high capacity retention of 80 % at a high current density of 20 A/g. The assembled asymmetric supercapacitor (ASC) device delivers a high energy density of 43.3 Wh kg−1 at a power density of 899 W kg−1 and exhibits superior cycling stability with the capacity retention of 88 % after 5,000 cycles. Subsequently, the fabricated all-solid-state ASC device shows an excellent energy density of 36.4 Wh kg−1 with a power density of 824 W kg−1. This work proposing rational design of combining multicomponent sulfides and core–shell heterostructure based on PBA nanocubes opens up a novel route for developing asymmetric supercapacitor electrode materials with superior performance. [ABSTRACT FROM AUTHOR]

Hydrogen energy as the alternative to fossil fuel received wide attention. Among different methods of hydrogen production, water electrolysis is the cleanest and most promising method. However, its development is greatly limited by hydrogen evolution reaction (HER) reaction and oxygen evolution reaction (OER) reaction. Therefore, it is very necessary to develop low-cost, high activity, and good stability of non-precious metal catalyst to replace the precious metal catalyst (Pt, RuO2), and to further reduce overpotential and power consumption. To date, great efforts have been made to develop transition metal compounds with electrocatalytic performance, such as sulfides, oxides, and carbides materials. Especially, transition metal sulfides play a very important role as catalysts and have attracted wide attention for their structural adjustability, high abundance, and mild preparation process. In this introduction, we focus on the role of transition metal sulfides in catalysts for water electrolysis, especially in a few most studied sulfides such as cobalt/molybdenum based sulfides and the recently reported homogeneous cobalt-molybdenum based sulfides, in which cobalt acts as a key element. Composition, morphology, and size are the most important factors that influence the intrinsic activity, electrical conductivity, and electronic structure of these transition metal sulfides. Besides, the effect of carbon nanomaterials as carrier materials is also discussed. The aim of this review is to emphasize the great potentials of cobalt and molybdenum based sulfides with high performance, and to help improve the performance of existing sulfides and explore new modification methods.

In this study, we synthesized a transition metal sulfide (TMS) with a spinel structure, i.e., MnIn2S4 (MIS), using a two-step hydrothermal and sintering process. In the context of lithium-ion battery (LIB) applications, ternary TMSs are being considered as interesting options for anode materials. This consideration arises from their notable attributes, including high theoretical capacity, excellent cycle stability, and cost-effectiveness. However, dramatic volume changes result in the electrochemical performance being severely limited, so we introduced single-walled carbon nanotubes (SWCNTs) and prepared an MIS/SWCNT composite to enhance the structural stability and electronic conductivity. The synthesized MIS/SWCNT composite exhibits better cycle performance than bare MIS. Undergoing 100 cycles, MIS only yields a reversible capacity of 117 mAh/g at 0.1 A/g. However, the MIS/SWCNT composite exhibits a reversible capacity as high as 536 mAh/g after 100 cycles. Moreover, the MIS/SWCNT composite shows a better rate capability. The current density increases with cycling, and the SWCNT composite exhibits high reversible capacities of 232 and 102 mAh/g at 2 A/g and 5 A/g, respectively. Under the same conditions, pristine MIS can only deliver reversible capacities of 21 and 4 mAh/g. The results indicate that MIS/SWCNT composites are promising anode materials for LIBs. [ABSTRACT FROM AUTHOR]

This manuscript reports the facile preparation of Co-NSC@CBC84 porous carbon-based and self-supported catalysts containing Co 9 S 8 active species by pyrolysis and sulfidation of ZIF-67 in-situ grown on polydopamine-modified biomass bacterial cellulose. Owing to the strong synergy effect between Co-NSC nanoparticles and CBC substrate, Co-NSC@CBC84 is superior to other reported cobalt-based sulfide catalytic materials and has good stability in acidic electrolyte. [Display omitted] Metal-organic framework (MOF) derived transition metal-based electrocatalysts have received great attention as substitutes for noble metal-based hydrogen evolution catalysts. However, the low conductivity and easy detachments from electrodes of raw MOF have seriously hindered their applications in hydrogen evolution reaction. Herein, we report the facile preparation of Co-NSC@CBC84, a porous carbon-based and self-supported catalyst containing Co 9 S 8 active species, by pyrolysis and sulfidation of in-situ grown ZIF-67 on polydopamine-modified biomass bacterial cellulose (PDA/BC). As a binder-free and self-supported electrocatalyst, Co-NSC@CBC84 exhibits superior electrocatalytic properties to other reported cobalt-based sulfide catalytic materials and has good stability in 0.5 M H 2 SO 4 electrolyte. At the current density of 10 mA cm−2, only an overpotential of 138 mV was required, corresponding to a Tafel slope of 123 mV dec−1, owing to the strong synergy effect between Co-NSC nanoparticles and CBC substrate. This work therefore provides a feasible approach to prepare self-supported transition metal sulfides as HER catalysts, which is helpful for the development of noble metal-free catalysts and biomass carbon materials. [ABSTRACT FROM AUTHOR]

Anchoring of single-atom Pt2+ and Pt0 on the surface of Sb 2 S 3 NRs highly benefits to the formation of metal (Pt)-semiconductor (Sb 2 S 3) electric interaction, which synergistically improves the broadband light harvesting and promotes the Sb 2 S 3 -to-Pt electron transfer following inhibited photoexciton recombination kinetics and enhanced H proton adsorption capacity, resulting higher and more durable photoactivity for H 2 O-to-H 2 conversion. [Display omitted] • Single atomic Pt2+/Pt0 active sites were successfully anchored on the Sb 2 S 3 nanorods. • The metal (Pt)-semiconductor (Sb 2 S 3) electric interaction was formed. • The optimal composite catalyst possesses enhanced H proton adsorption capacity. • Higher and more durable photoactivity for H 2 O-to-H 2 conversion were achieved. • The mechanism of multisite cocatalysis for photoactivity improvement was elucidated. Single atomic metal (SAM) cocatalysis is a potential strategy to improve the performance of photocatalytic materials. However, the cocatalytic mechanism of SAM sites in different valence states is rarely reported. Herein, single atomic Pt2+/Pt0 active sites were anchored on Sb 2 S 3 nanorods to synergistically improve the photoactivity for hydrogen production under simulated sunlight. Experimental results and density functional theory calculations indicated that the coexistence of single atomic Pt2+/Pt0 sites synergistically improves the broadband light harvesting and promotes the Sb 2 S 3 -to-Pt electron transfer following inhibited photoexciton recombination kinetics and enhanced H proton adsorption capacity, resulting higher and more durable photoactivity for hydrogen production. Therefore, the optimal Sb 2 S 3 -Pt 0.9‰ composite catalyst achieved remarkably enhanced hydrogen evolution rate of 1.37 mmol∙g−1∙h−1 (about 105-fold greater of that of Sb 2 S 3 NRs) under faintly alkaline condition, and about 5.41 % of apparent quantum yield (AQY 700 nm) was achieved, which shows obvious superiority in hydrogen production by contrasting with the reported Sb 2 S 3 -based photocatalysts and conventional semiconductor photocatalytic materials modified with noble metals. This study elucidate a well-defined mechanism of multisite cocatalysis for photoactivity improvement. [ABSTRACT FROM AUTHOR]

Although in‐plane heterostructure with high ion transport pathway and unique interfacial atomic structure offers endless possibilities in the catalysis field, it is still challenging to directly synthesize MXene‐based in‐plane heterostructure due to the differences in crystal structures and growth conditions. Here, Mo2C–MoS2 in‐plane multi‐heterostructures are synthesized by topological conversion of sandwich‐like mesoporous Mo2C–SiO2 layers in sulfur vapor and subsequent removal of SiO2. During the conversion process, the exposed Mo2C will efficiently converted to 2H phase MoS2, meanwhile, the covered Mo2C remained stable, affording metallic Mo2C MXene and semiconducting MoS2 in‐plane multi‐heterostructures compatible in one layer. The resultant Mo2C–MoS2 layer has multiple heterointerfaces, build‐in electric fields as well as abundant defects. Such structural features enable to improve of the electrochemical active surface area (16.4 mF cm−2), which not only facilitates the bidirectional sulfur electrochemistry between solid Li2S and soluble lithium polysulfides, but also enhances the transfer kinetics of electrons and ions, giving rise to a high‐rate performance (642 mAh g−1 at 5 C) and a long‐term cycle life (1000 cycles at 5 C) in lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]

We treated the reconstruction process of pyrite-type transition metal sulfides (TMSs) during oxygen evolution reaction (OER) process as a potential-dependent electrochemical reaction similar to OER, i.e. , sulfide oxidation reaction (SOR). Based on this analysis method, the reconstruction mechanism of various TMSs was elucidated and new descriptors for TMSs reconstruction were proposed: U SOR and ΔU, which provides a significant contribution to the understanding of the mechanism and quantifying this surface behavior. [Display omitted] Reconstruction universally occurs over non-layered transition metal sulfides (TMSs) during oxygen evolution reaction (OER), leading to the formation of active species metal (oxy)hydroxide and thus significantly influences the OER performance. However, the reconstruction process and underlying mechanism quantitatively remain largely unexplored. Herein, we proposed an electrochemical reaction mechanism, namely sulfide oxidation reaction (SOR), to elucidate the reconstruction process of pyrite-type TMSs. Based on this mechanism, we evaluated the reconstruction capability of NiS 2 doped with transition metals V, Cr, Mn, Fe, Co, Cu, Mo, Ru, Rh, and Ir within different doped systems. Two key descriptors were thus proposed to describe the reconstruction abilities of TMSs: U SOR (the theoretical electric potential of SOR) and ΔU (the difference between the theoretical electric potential of SOR and OER), representing the initiation electric potential of reconstruction and the intrinsic reconstruction abilities of TMSs, respectively. Our finding shows that a lower U SOR readily initiate reconstruction at a lower potential and a larger ΔU indicating a poorer reconstruction ability of the catalyst during OER. Furthermore, Fe-doped CoS 2 was used to validate the rationality of our proposed descriptors, being consistent with the experiment findings. Our work provides a new perspective on understanding the reconstruction mechanism and quantifying the reconstruction of TMSs. [ABSTRACT FROM AUTHOR]

Abstract Supercapacitor (SC) devices holds an important position between traditional capacitors and ion batteries in terms of energy density and power density values. In particular, SC′s greater power density values than Li‐ion batteries make them useful for some specific applications, such as storing energy in hybrid cars while the car slows down. Increasing energy density values is one of the key challenges for the SC community. Transition metal dichalcogenides (TMDCs), are one of the new developing important material systems to have this potential, compared to their counterparts’ transition metal oxides and conductive polymers. This review is about giving insight into the electrochemical performances of two‐dimensional (2D) layered transition metal sulfides (TMS) such as MoS2, WS2, TaS2, NbS2, VS2, TiS2 and ZrS2 materials. On the other hand, the methods mostly used in synthesizing these materials are presented.

Abstract The commercialization of Li−S batteries is seriously hindered by polysulfides with severe shuttle effect, and the inherent insulating properties and slow reaction kinetics of insoluble Li2S products. Transition metal sulfides (TMSs) have a high adsorption capacity for polysulfides and have been shown to have a strong catalytic effect on polysulfide conversion reactions. This paper reviews the research on the application of Unary TMSs, heterostructures, etc. in Li−S batteries, and gives some research methods for TMD catalysts in Li−S batteries. Finally, it points out the main focuses and direction of future Li−S battery research and development. It aims to provide some insights into the design and manufacture of advanced Li−S batteries for commercial use.

In this paper, we report the use of femtosecond radially polarized vortex laser with MHz repetition rate for direct writing of cladding waveguides (WGs) and realization of waveguide laser oscillations in ytterbium-doped calcium fluoride crystal. The negative refractive index modification in Yb:CaF2 crystal is fabricated by the homemade all-fiber laser amplifier. At 976 nm pump wavelength, these Yb:CaF2 WGs can achieve continuous-wave (CW) laser oscillation. The length of resonant cavity is 4 mm, and the minimum laser threshold is 116 mW, corresponding to the propagation loss of 0.85 dB/cm, the center wavelength of 1045.2 nm, and the maximum output power of 91 mW. In addition, a saturable absorber mirror (SAM) was prepared by depositing ReS0.8Se1.2 on the reflective surface of a dichroic mirror to realize Q-switched waveguide laser output. The output Q-switched pulses with a tunable repetition rate in the range of 125–692.5 kHz, and the shortest pulse duration is 513 ns.

Electrochemical decomposition of water to produce hydrogen is an ideal clean fuel that promises to solve problems such as energy depletion and environmental pollution. Transition metal sulfides(TMS M = Fe, Co, Ni) have been widely explored and studied for their potential in oxygen evolution reactions (OER). However, due to their thermodynamic instability, surface reconstruction inevitably occurs during the OER process, forming oxides or (oxygen) hydroxide active species in situ. This process poses a great challenge to reveal the true active sites and the reaction mechanism. Therefore, a fundamental understanding of the catalyst surface reconstruction process is essential for the design of efficient catalysts. To this end, we want to explore the following issues, (1) determine the catalyst activity origin and structural evolution process, (2) clarify the reconstruction mechanism and establish the conformational relationships (3) manipulate the in situ catalyst surface reconstruction through rational modulation strategies. In this review, we summarize and discuss the recent progress of TMS as OER precatalysts, revealing the catalyst reconstruction behavior based on in situ operation techniques, DFT calculations, highlighting the most effective strategies to adjust TMS surface reconstruction.It provides a more comprehensive understanding of the surface reconstruction of TMS, as well as reference for the design and optimization of efficient and stable catalysts. [Display omitted] • Summarized the advances on surface reconstruction of TMS as precatalysts for OER. • Presenting a basic understanding of reconstruction behavior. • Revealed the active origin and catalytic mechanism of surface reconstruction. • The effective regulation of TMS surface reconstruction strategy is highlighted. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur (Li−S) batteries show advantage of high theoretical capacity. However, the shuttle effect of polysulfides and sluggish sulfur redox kinetics seriously reduce their service life. Inspired by the porous structural features of biomass materials, herein, a functional interlayer is fabricated by silkworm excrement‐derived three‐dimensional porous carbon accommodating nano sized CoS2 particles (SC@CoS2). The porous carbon delivers a high specific surface area, which provides adequate adsorption sites, being responsible for suppressing the shuttle effect of polysulfides. Meanwhile, the porous carbon is favorable for hindering the aggregation of CoS2 and maintaining its high activity during extended cycles, which effectively accelerates the polysulfides conversion kinetics. Moreover, the SC@CoS2 functional interlayer effectively limits the formation of Li dendrites and promotes the uniform deposition of Li on the Li electrode surface. As a result, the CMK‐3/S cathode achieves a high initial capacity of 1599.1 mAh g−1 at 0.2 C rate assisted by the polypropylene separator coated with the functional interlayer and 1208.3 mAh g−1 is maintained after the long cycling test. This work provides an insight into the designing of long‐lasting catalysts for stable functional interlayer, which encourages the application of biomass‐derived porous carbon in high‐energy Li−S batteries. [ABSTRACT FROM AUTHOR]

Fe@CoMo 2 S 4 /Ni 3 S 2 /NF catalysts with enhanced conductivity, enlarged electochemical active areas and modulated electronic structure for efficient water splitting. [Display omitted] Oxygen evolution reaction (OER) is a multi-electron transfer process, whose intrinsic sluggish dynamic restricts the whole process of overall water splitting (OWS). To address this issue, a porous transition metal sulfide (TMS) catalyst with rich heterojunctions was prepared by vulcanization and trace Fe doping of CoMo-based metal–organic framework (MOF). In this work, the nanoflower composed of ultrathin 2D nanosheets anchored on a nickel foam presents a layered interface that contributes to the exposure of active regions. The resulting electrode denoted as Fe@CoMo 2 S 4 /Ni 3 S 2 /NF required a low overpotential (η 10 = 167 mV @ 10 mA cm−2, η 50 = 260 mV @ 50 mA cm−2) in 1.0 M KOH for OER and a small cell voltage (E = 1.513 V @ 10 mA cm−2) to power OWS when coupled with commercial Pt/C. It also exhibited splendid morphological and chemical stability with virtually invariant polarization curve and flower-like appearance after 1000 CV cycles, as well as long-term durability over 100 h with a constant current density of 10 mA cm−2. This work revealed the multi-anionic regulation mechanism in the surface reconstruction of sulfide electrocatalysts, and verified that Co/Mo/Ni-based oxysulfide was the true active substance of OER, which inspired the understanding and design of multi-anionic regulated electrocatalysts. [ABSTRACT FROM AUTHOR]

In this work, CuCo@C and CuCoS@C derived from an in-situ synthesis bi-metallic MOF HKUST-1/ZIF-67 (CuCo-MOF) were successfully fabricated by calcination and hydrothermal sulfide strategies. Morphology characterization results indicated that ZIF-67 grew uniformly on the surface of HKUST-1 to form CuCo-MOF. And, benefiting from bi-metallic MOFs precursors, the formed derivatives inherited and possessed good textural properties and dispersing well metal sites, which facilitated diffusions of molecules and enhancements of catalytic performances. In addition, carbon matrix produced in the materials further accelerated electron transporting properties, boosting HER and OER activities. Accordingly, in electrolytic water evaluations, CuCo@C and CuCoS@C showed good HER and OER performance, achieving 97 mV and 180 mV of overpotential at 10 mA cm−2 in an alkaline medium, respectively. Additionally, the catalysts exhibit long-term stabilities. Thus, this study provides a rational way for designing and constructing of high-efficient catalysts for H2 and O2 generations from electrolytic water processes. [ABSTRACT FROM AUTHOR]

The tetracarbonyl complexes of transition metal chalcogenides M2X2(CO)4, where M = Fe, Co, Ni, Cu and X = S, Se, are examined by density functional theory (DFT). The M2X2 core is cyclic with either planar or non-planar geometry. As a sulfide, it is present in natural enzymes and has a selective redox capacity. The reduced forms of the selenide and sulfide complexes are relevant to the hydrogen evolution reaction (HER) and they provide different positions of hydride ligand binding: (i) at a chalcogenide site, (ii) at a particular cation site and (iii) in a midway position forming equal bonds to both cation sites. The full pathway of water decomposition to molecular hydrogen and oxygen is traced by transition state theory. The iron and cobalt complexes, cobalt selenide, in particular, provide lower energy barriers in HER as compared to the nickel and copper complexes. In the oxygen evolution reaction (OER), cobalt and iron selenide tetracarbonyls provide a low energy barrier via OOH* intermediate. All of the intermediate species possess favorable excitation transitions in the visible light spectrum, as evidenced by TD-DFT calculations and they allow photoactivation. In conclusion, cobalt and iron selenide tetracarbonyl complexes emerge as promising photocatalysts in water splitting. [ABSTRACT FROM AUTHOR]

In this paper, we report the use of femtosecond radially polarized vortex laser with MHz repetition rate for direct writing of cladding waveguides (WGs) and realization of waveguide laser oscillations in ytterbium-doped calcium fluoride crystal. The negative refractive index modification in Yb:CaF2 crystal is fabricated by the homemade all-fiber laser amplifier. At 976 nm pump wavelength, these Yb:CaF2 WGs can achieve continuous-wave (CW) laser oscillation. The length of resonant cavity is 4 mm, and the minimum laser threshold is 116 mW, corresponding to the propagation loss of 0.85 dB/cm, the center wavelength of 1045.2 nm, and the maximum output power of 91 mW. In addition, a saturable absorber mirror (SAM) was prepared by depositing ReS0.8Se1.2 on the reflective surface of a dichroic mirror to realize Q-switched waveguide laser output. The output Q-switched pulses with a tunable repetition rate in the range of 125–692.5 kHz, and the shortest pulse duration is 513 ns. [ABSTRACT FROM AUTHOR]

Layered guest carbon materials could induce interlayer engineering, especially in regulating the interlayer structure and electronic properties of the hosts, leading to high performance in Li‐ion batteries (LIBs). Here, crystalline graphdiyne oxide (GDYO) is successfully inserted into MoS2 gallery via electrostatic self‐assembly. Experimental and theoretical data show that GDYO‐embedding induces interlayer engineering of MoS2 causing (i) enlarged MoS2 interlayer distance (supplying additional Li‐ion diffusion channels and storage sites and mitigating volume change), (ii) creating interfacial electric fields (significantly improving Li‐ion transport kinetics), (iii) limiting the electrochemical products of Mo and soluble lithium polysulfide (MoS2 structure regeneration), and (iv) regulation of the interfacial current density distribution during the electrochemical reaction (uniform Li plating). Moreover, through systematic ex situ and in situ investigations, the triple‐mechanism of Li‐ion storage is thoroughly elucidated in the heterostructure, emphasizing the positive effects of GDYO intercalation on the interfacial and interlayer storage as well as the phase conversion processes. Such a MoS2/GDYO anode exhibits high reversible capacity (≈652.6 mAh g−1 at 2.0 A g−1) and superior cyclic stability of 655.1 mAh g−1 after 1000 cycles. GDYO‐induced interlayer engineering based on host–guest chemistry can provide new ideas for designing effective heterostructures for high‐performance energy storage and conversion systems. [ABSTRACT FROM AUTHOR]

With the rapid improvement of compact smart devices, fabricating anode materials with high volumetric capacity has gained substantial interest for future sodium‐ion batteries (SIBs) applications. Herein, a novel bimetal sulfide CuCo5S8 material is proposed with enhanced volumetric capacity due to the intrinsic metallic electronic conductivity of the material and multi‐electron transfer during electrochemical procedures. Due to the intrinsic metallic behavior, the conducting additive (CA) could be removed from the electrode fabrication without scarifying the high rate capability. The CA‐free CuCo5S8 electrode can achieve a high volumetric capacity of 1436.4 mA h cm−3 at a current density of 0.2 A g−1 and 100 % capacity retention over 2000 cycles in SIBs, outperforming most metal chalcogenides, owing to the enhanced electrode density. Reversible conversion reactions are revealed by combined measurements for sodium systems. The proposed new strategy offers a viable approach for developing innovative anode materials with high‐volumetric capacity. [ABSTRACT FROM AUTHOR]

Transition metal sulfides (TMSs) are considered to be highly promising electrode materials for supercapacitors. Optimizing the structure of the electrode materials to expose more active sites is a crucial strategy for boosting the electrochemical performance. Herein, we developed carbon/metal sulfide composite electrode materials by anchoring nickel–cobalt bimetallic sulfide nanosheets (NCS) on chitosan-derived heteroatom-doped hierarchical porous carbon (CPC). The composite materials exhibited a uniform distribution and significantly increased active sites, which led to a substantial enhancement of the electrochemical properties. The optimal sample NCS/CPC-3 exhibited a brilliant capacitive performance and great cycling stability. Also, the assembled asymmetric supercapacitor presented a robust energy output of 37.1 W h kg–1 at 800.0 W kg–1. In addition, NCS/CPC-3 also demonstrated potential in the field of small-molecule detection. Our findings supply a unique perspective on effectively boosting the electrochemical properties of TMS-based electrode materials. [ABSTRACT FROM AUTHOR]

Water electrolysis technology is considered to be one of the most promising means to produce hydrogen. Herein, aiming at the problems of high overpotential and slow kinetics in water splitting, N-doped porous carbon nanofibers-coupled CoNi2S4 nanoparticles are prepared as bifunctional electrocatalyst. In the strategy, NaCl is used as the template to prepare porous carbon nanofibers with a large surface area, and sulfur vacancies are created to modulate the electronic structure of CoNi2S4. Electron spin resonance confirms the formation of abundant sulfur vacancies, which largely reduce the bandgap of CoNi2S4 from 1.68 to 0.52 eV. The narrowed bandgap is conducive to the migration of valence electrons and decreases the charge transfer resistance for electrocatalytic reaction. Moreover, the uniform distribution of CoNi2S4 nanoparticles on carbon nanofibers can prevent the aggregation and facilitate the exposure of electrochemical active sites. Therefore, the composite catalyst exhibits low overpotentials of 340 mV@100 mA·cm−2 for oxygen evolution reaction and 380 mV@100 mA·cm−2 for hydrogen evolution reaction. The assembled electrolyzer requires 1.64 V to achieve 10 mA·cm−2 for overall water-splitting with good long-term stability. The excellent performance results from the synergistic effect of porous structures, sulfur deficiency, nitrogen doping, and the well-dispersed active component. [ABSTRACT FROM AUTHOR]

Transition metal sulfides have emerged as highly promising materials in thermoelectrics owing to their economic viability and sustainable characteristics. Herein, we developed entropy-engineered sulfides based on TiS2. The process of equal doping at Ti sites resulted in a notable reduction in lattice thermal conductivity due to point defects and phase segregation induced by entropy engineering; however, it also had a substantial detrimental effect on the Seebeck coefficient. Finally, by incorporating minor doping at Ti sites with Zr, Nb and Ta, each at a concentration of 1 at%, an impressive figure of merit of 0.38 was achieved at 625 K because minor doping was able to maintain the large Seebeck coefficient while simultaneously reducing the lattice thermal conductivity. This study not only illuminates the significant role of entropy engineering in reducing lattice thermal conductivity but also sparks interest in the potential of equivalent doping at sulfur sites for future investigations.

Heterogeneous catalysis is essential to most industrial chemical processes. To achieve a better sustainability of these processes we need highly efficient and highly selective catalysts that are based on earth-abundant materials rather than the more conventional noble metals. Here, we discuss the potential of inorganic materials as catalysts for chemical transformations focusing in particular on the promising transition metal phosphides and sulfides. We describe our recent and current efforts to understand the interfacial chemistry of these materials that governs catalysis, and to tune catalytic reactivity by controlled chemical modification of the material surfaces and by use of interfacial electric fields.

Developing a reasonable design of a lithiophilic artificial solid electrolyte interphase (SEI) to induce the uniform deposition of Li+ ions and improve the Coulombic efficiency and energy density of batteries is a key task for the development of high-performance lithium metal anodes. Herein, a high-performance separator for lithium metal anodes was designed by the in situ growth of a metal–organic framework (MOF)-derived transition metal sulfide array as an artificial SEI on polypropylene separators (denoted as Co9S8-PP). The high ionic conductivity and excellent morphology provided a convenient transport path and fast charge transfer kinetics for lithium ions. The experimental data illustrate that, compared with commercial polypropylene separators, the Li//Cu half-cell with a Co9S8-PP separator can be cycled stably for 2000 h at 1 mA cm−2 and 1 mAh cm−2. Meanwhile, a Li//LiFePO4 full cell with a Co9S8-PP separator exhibits ultra-long cycle stability at 0.2 C with an initial capacity of 148 mAh g−1 and maintains 74% capacity after 1000 cycles. This work provides some new strategies for using transition metal sulfides to induce the uniform deposition of lithium ions to create high-performance lithium metal batteries.

Amino acids are one of the most important building blocks of life. During the biochemical process of translation, cells sequentially connect amino acids via amide bonds to synthesize proteins, using the genetic information in messenger RNA (mRNA) as a template. From a prebiotic perspective (i.e., without enzymatic catalysis), joining amino acids to peptides via amide bonds is difficult due to the highly endergonic nature of the condensation reaction. We show here that amides can be formed in reactions catalyzed by the transition metal sulfides from acetylene, carbon monoxide and ammonia under aqueous conditions. Some α- and β-amino acids were also formed under the same conditions, demonstrating an alternative cyanide-free path for the formation of amino acids in prebiotic environments. Experiments performed with stable isotope labeled precursors, like 15NH4Cl and 13C-acetylene, enabled the accurate mass spectroscopic identification of the products formed from the starting materials and their composition. Reactions catalyzed using the transition metal sulfides seem to offer a promising alternative pathway for the formation of amides and amino acids in prebiotic environments, bypassing the challenges posed by the highly endergonic condensation reaction. These findings shed light on the potential mechanisms by which the building blocks of life could have originated on early Earth.

Transition metal sulfides (TMS) have been receiving specific attention due to their excellent physiochemical properties and electrochemical activity. In this article, we demonstrate the synthesis of sea-urchin-like Bi2S3 combined with MoS2 hierarchical nanoflowers via a hydrothermal route for electrochemical sensing of Flufenamic acid (FMA). FMA is one of the non-steroidal anti-inflammatory drugs (NSAIDs) which endangers human health. The Bi2S3/MoS2 composite's formation was confirmed by various characterizations via microscopic and spectroscopic techniques. The synergistic effect between the two metal sulfides improves electron transport and enables more active sites. Under optimal conditions, the resultant nanocomposite exhibits a high sensitivity value (0.44 ​μA ​μM−1 ​cm−2), a reasonable limit of detection (0.009 ​μM), and a broad linear range (0.01 – 453 ​μM). Furthermore, the electrochemical detection of FMA in biological samples was achieved with good reliability and decent recovery.

Electrochemical water splitting is one of the ways to produce clean energy. However, oxygen evolution reaction (OER), an important half-reaction involving complex four-electron transfer, significantly reduces the overall water splitting efficiesncy. Tn this paper, by means of interface engineering. Ni(OH)2/CeO2 hybrid particles were modified with Nis nanosheet arrays grown in situ on nickel foam (NF) by electrodeposition, so as to successfully prepare an efficient and stable OER composite electrode. Scanning electron microscopy (SEM), X-ray diffraction (XRT)) and X-ray photoelectron spectroscopy (XPS) were used to characterize and analyze the microstructure, phase composition and surface element valence of the electrode materials. Tn the 1.0 M KOH electrolyte, the overpotential required to drive the current density of 100 mA/cm² is only 330 mV, the Tafel slope is 150.7 mV/dec, and the durability can be maintained for at least 25 h. The excellent electrocatalytic performance is due to the synergistic catalytic effect of Ni(0H)2/CeO2 particles and Nis nanoarray and the promotion of Ce1+ cations on the formation of OER active components. This study confirms that rare earth compounds have certain potential in modifying sulfide catalysts and can be widely used in the field of energy catalysis. [ABSTRACT FROM AUTHOR]

Cobalt sulfides are considered as promising candidates for lithium-ion battery (LIB) anode materials with high energy densities. Their energy storage mechanism is widely understood to involve the traditional intercalation and conversion reaction. However, these conventional mechanisms are unable to explain the storage capacities of certain materials which exceed the theoretical limit. Here, utilizing advanced in situ magnetometry to detect the magnetization evolution of Co1-x S LIBs in real time, it is demonstrated that the Co-catalytic lithium storage process and interfacial space charge storage mechanism are strongly related to the additional capacity of cobalt sulfides. During discharge, a Co/Li2 S interface is formed, wherein the Co nanoparticles and Li2 S could store a large amount of polarized electrons Li+, respectively. Subsequently, the electrons stored in Co are transferred to the polymeric film, forming radical anions and contributing extra capacity. These findings reveal the charge storage mechanisms of transition metal sulfides and highlight the critical role of magnetic testing in the investigation of energy storage mechanisms. [ABSTRACT FROM AUTHOR]