查看更多>>摘要：Single-atom catalysts have risen significant attention in the realm of green electrocatalytic energy conversion to address energy and environmental sustain-ability challenges.Transition metal dichalcogenide(TMD)-based single-atom catalysts are considered highly effective in electrocatalysis due to the TMDs'notable specific surface area,tunable elemental species and efficient utilization of single atoms.In order to enhance electrocatalytic performance,it is imperative to elaborately engineer the local environment surrounding the active sites of single atoms within TMDs.In this review,we initially explore the effects of synthesis methods on single-atom active sites and the influence of loading of single atoms on catalytic performance for TMDs.The modulation strategies of the local environment surrounding single-atom sites in TMDs are elaborated,including substitution engineering,surface adsorption,vacancies,spatial confinement and dual-atom site strategies.For each modulation strategy,the effects of diverse local environments on various electro-catalytic applications are presented,such as the oxygen evolution reaction,oxygen reduction reaction,nitrogen reduction reaction,CO2 reduction reaction and CO oxida-tion.Ultimately,this study presents a comprehensive overview of the challenges encountered and the potential directions for the advancement of single-atom catalysts based on TMDs in the realm of electrocatalysis.
查看更多>>摘要：The ferroelectric semiconductor material PbTiO3 exhibits remarkable spontaneous polarization and photoelectric properties,positioning it as a promising polar photocatalyst.The internal electric field of ferroelectrics can separate photocarriers and enhance the catalytic per-formance of photocatalysts.Moreover,when combined with other semiconductors,PbTiO3 contributes to the construction of a depolarization field,extending the cat-alytic applications of PbTiO3 catalysts.PbTiO3 exhibits optical absorption,semiconductor,and piezoelectric prop-erties.Its piezoelectric polarization field enhances charge separation,modulates band structure,surface charge con-duction,and heterojunction interface charge conduction,thereby amplifying photocatalytic activity.This paper begins by examining the structure,properties,and prepa-ration methods of PbTiO3.Subsequently,it delves into the optimization of PbTiO3's structure and performance,exploring applications in photocatalysis as a ferroelectric photocatalyst.Emphasis is placed on the detailed discus-sion of surface modification,heterostructure formation,and ferroelectric polarization of PbTiO3 ferroelectrics.These aspects are thoroughly explored for their role in regulating activity and optimizing the performance of photocatalysis and photopiezoelectric catalysis.In conclusion,the paper addresses the current research status of PbTiO3 ferroelec-tric materials and highlights the challenges that lie ahead.The intention is to provide valuable references for the ongoing research in PbTiO3 ferroelectric materials.
查看更多>>摘要：K-ion batteries(KIBs)have drawn much attention due to the abundant potassium reserves and wide accessibility as well as high energy density,which can be designed for large-scale energy storage systems.As the most promising anode materials for KIBs,graphitic car-bons,especially those with an intermediate structure between the crystalline graphite and amorphous carbons become a hot research focus because of the improved rate capability and enhanced diffusion-controlled capacity at low voltage regions.Herein,we first review the structures of graphitic carbons in the view of graphitic domains and the structure changes in their K-ion intercalation com-pounds.Then,we summarize the preparation mechanisms and characterizations of graphitic carbons and the influence factors in their degree of graphitization.Furtherly,we illustrate the strategies to optimize their K-ion storage properties from four aspects,namely graphitic domain design,microstructure engineering,electrochemical active component regulation,and defect engineering.Finally,we propose the issues that urgently need to be solved in gra-phitic carbons and the possible solutions.We hope that this view could offer some inspiration for the further designing and optimizing of graphitic carbons for practical KIBs.
查看更多>>摘要：Supercapacitors(SCs)have remarkable energy storage capabilities and have garnered considerable interest due to their superior power densities and ultra-long cycling characteristics.However,their comparatively low energy density limits their extensive application in large-scale commercial applications.Electrode materials directly affect the performance of SCs.Thus,the development of cutting-edge electrode materials and modification of their morphological and structural properties are vital for advancing the performance of SCs.Transition metal compounds have a high specific capacity and good cycling durability,making them the most promising electrode active materials for high-energy density SCs.Nevertheless,their inadequate conductivity,unfavorable ion diffusion rates,substantial volume expansion and phase transitions during charging and discharging are obstacles to their stable and efficient integration into SCs.To address these challenges,this study provides a comprehensive summary of the current advancements in transition metal nanoma-terials as electrode materials for SCs,an overview of the current research status,and the prevailing challenges.Furthermore,this study highlights synthetic techniques and management strategies for electrode materials derived from transition metal compounds,targeting the resolution of the aforementioned challenges.Finally,a concise discussion is provided on the future directions of SC development,with an emphasis on the utilization of transition metal com-pound electrode materials.
查看更多>>摘要：Thermoelectric materials possess the unique capability to convert thermal energy into electric energy and vice versa,making them promising for waste heat recovery and efficient cooling systems.Currently,exten-sively investigated thermoelectric materials such as Bi2Te3,PbTe and GeTe exhibit superior thermoelectric properties at room temperature and medium temperature regions.However,the broad application of these thermoelectric materials has been impeded by the high cost and restricted accessibility of Te and Ge in the earth's crust.Over the past few years,researchers have shown increasing interest in PbSe-and PbS-based materials,primarily attributed to their abundant elemental supply and relatively low costs.The assessment of research progress and a comprehensive overview of optimization strategies in time can signifi-cantly contribute to further improving the thermoelectric performance.These strategies include optimizing carrier concentration(aliovalent doping,dynamic doping and defect state),enhancing density-of-state effective mass(band convergence,band flattening and energy filtering effect),optimizing carrier mobility(band sharpening and band alignment)and reducing lattice thermal conductivity(all-scale hierarchical defect structures designing).This systematic summary and analysis provide novel insights and perspectives for the development of thermoelectric materials.
查看更多>>摘要：The critical role of vanadium in metallurgy and the increasing commercialization of vanadium redox flow batteries have contributed to a rise in market demand for vanadium,emphasizing the need to ensure the sustain-ability of vanadium production.Converter vanadium slag and stone coal,generated during the smelting process of vanadium-titanium magnetite,serve as primary raw materials for vanadium extraction.This paper reviews the process mineralogy of converter vanadium slag and stone coal,encompassing the chemical and physical phase compositions of the raw materials and the state of vana-dium occurrence.The aim is to establish a theoretical foundation for the mechanistic study of the vanadium extraction techniques and to provide a reference for the optimization of the process afterward.This paper system-atically summarizes the current vanadium extraction tech-nology from converter vanadium slag,covering roasting,direct leaching,sub-molten salt method,and the technol-ogy and research status of vanadium extraction from stone coal.Most importantly,it identifies key issues in the cur-rent vanadium extraction techniques and challenges faced in actual production,based on the analysis of the current vanadium extraction process and mechanism research.The forward feasibility and prospects for the development of vanadium extraction technology are outlined.
查看更多>>摘要：Lithium-sulfur batteries(LSBs)have already developed into one of the most promising new-generation high-energy density electrochemical energy storage sys-tems with outstanding features including high-energy density,low cost,and environmental friendliness.How-ever,the development and commercialization path of LSBs still presents significant limitations and challenges,partic-ularly the notorious shuttle effect triggered by soluble long-chain lithium polysulfides(LiPSs),which inevitably leads to low utilization of cathode active sulfur and high battery capacity degradation,short cycle life,etc.Substantial research efforts have been conducted to develop various sulfur host materials capable of effectively restricting the shuttle effect.This review firstly introduces the funda-mental electrochemical aspects of LSBs,followed by a comprehensive analysis of the mechanism underlying the shuttle effect in Li-S batteries and its profound influence on various battery components as well as the overall bat-tery performance.Subsequently,recent advances and strategies are systematically reviewed,including physical confinement,chemisorption,and catalytic conversion of sulfur hosts for restricting LiPSs shuttle effects.The interplay mechanisms of sulfur hosts and LiPSs are dis-cussed in detail and the structural advantages of different host materials are highlighted.Furthermore,key insights for the rational design of advanced host materials for LSBs are provided,and the upcoming challenges and the pro-spects for sulfur host materials in lithium-sulfur batteries are also explored.
查看更多>>摘要：With distinct advantages such as high gravi-metric and volumetric capacity(5855 mAh·cm-3 and 820 mAh·g-1),low redox potential(-0.762 V vs.standard hydrogen electrode(SHE)),high abundance,low toxicity and intrinsic safety of Zn metal anode,Zn-ion batteries have become a potential alternative to Li-ion batteries.However,several challenges still need to be addressed prior to the practical applications of Zn-ion batteries,such as dendrite growth during Zn plating/stripping and interfacial side reactions on the Zn surface.Such issues can be addressed by introducing additives to regulate the components and structures of the electrolyte.In this review,we systematically discussed the core issues of metallic Zn anodes and comprehensively summarized a novel perspective of the regulation mechanism of inhibit-ing dendrite growth or interfacial side reactions in Zn anodes by introducing additives into aqueous electrolytes.Furthermore,some discussions and prospects for aqueous Zn ion batteries(AZIBs)are presented for future research.
查看更多>>摘要：Proton exchange membrane fuel cells(PEMFCs)have been identified as a highly promising means of achieving sustainable energy conversion.A cru-cial factor in enhancing the performance of PEMFCs for further potential energy applications is the advancement in the field of catalyst engineering that has led to remarkable performance enhancement in facilitating the oxygen reduction reaction(ORR).Subsequently,it is important to acknowledge that the techniques used in preparation of membrane electrode assemblies(MEAs),the vital con-stituents of PEMFCs,also possess direct and critical influence on exhibiting the full catalytic activity of meticulously crafted catalysts.Here,a succinct summary of the most recent advancements in Pt catalysts for ORR was offered and their underly catalytic mechanism were dis-cussed.Then,both laboratory-scale and industrial-scale MEA fabrication techniques of Pt catalysts were summa-rized.Furthermore,a detailed analysis of the connections between materials,process,and performance in MEA fabrication was presented in order to facilitate the devel-opment of optimal catalyst layers.
查看更多>>摘要：Silicon-based(Si-based)materials offer more possibilities for generating new portable electronic devices due to their high specific capacities.However,their inferior electrical conductivity and volume expansion during cycling seriously limit their development.The optimum solution is to select specific materials to establish an exceptionally conductive and volume buffer structure,which can assist Si materials in developing their excellent lithium storage properties.In this study,Si particles were confined in TiO2 carbon fibers(TiO2 CFs)via electro-spinning,after which they were encapsulated with MXene and Co-MoS2(CMS)nanosheets to fabricate hierarchical ST-2@MXene@CMS films.TiO2 CF,MXene and CMS were employed to establish a coherent conductive network with one-,two-and three-dimensional electronic pathways to permit the unimpeded flow of electrons inside the electrode material.TiO2 CF,MXene and CMS acted pre-cisely as multilayered buffers to ameliorate the volume change of Si particles during cycling.In addition,the CMS nanosheets were involved in lithium storage,contributing to the final electrochemical performance.Ultimately,the ST-2@MXene@CMS films served as free-standing elec-trodes,avoiding the impact of inactive interfaces on the electrochemical performance and fulfilling the lightweight requirement for new energy storage devices.
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