The labels of VU1 and VU2 in Fig.1(b)of the paper[Chin.Phys.B 34046801(2025)]were not correctly placed.The correct figure is provided.This modification does not affect the result presented in the paper.
Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhi...Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhibit neat and well-defined kagome bands near the Fermi level,which are more easily realized in the absence of interlayer interactions.However,this absence also destabilizes the monolayer forms of many bulk kagome materials,posing significant challenges to their discovery.In this work,we propose a strategy to address this challenge by utilizing oxygen vacancies in transition metal oxides within a“1+3”design framework.Through high-throughput computational screening of 349 candidate materials,we identified 12 thermodynamically stable kagome monolayers with diverse electronic and magnetic properties.These materials were classified into three categories based on their lattice geometry,symmetry,band gaps,and magnetic configurations.Detailed analysis of three representative monolayers revealed kagome band features near their Fermi levels,with orbital contributions varying between oxygen 2p and transition metal d states.This study demonstrates the feasibility of the“1+3”strategy,offering a promising approach to uncovering low-dimensional kagome materials and advancing the exploration of their quantum phenomena.展开更多
The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(...The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(2)(M=Ti,Zr,and Hf)compounds are formed in bent insertion structures.The observed ground-state adiabatic detachment energy(ADE)is measured to be 1.597±0.003,1.651±0.003,and 2.119±0.003 eV for TiO_(2)^(-),ZrO_(2)^(-),and HfO_(2)^(-),respectively.The vibrational frequencies of the anionic and neutral MO_(2)are also determined from the experimental spectra.The results of theoretical calculations show that the electronic configurations of MO_(2)^(-)are^(2)A_(1)with C_(2v)point group.Bond order analysis indicates that the two M-O bonds are all multiple characters.展开更多
Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demo...Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.展开更多
As a main oxidizer in solid composite propellants,ammonium perchlorate(AP)plays an important role because its thermal decomposition behavior has a direct influence on the characteristic of solid composite propellants....As a main oxidizer in solid composite propellants,ammonium perchlorate(AP)plays an important role because its thermal decomposition behavior has a direct influence on the characteristic of solid composite propellants.To improve the performance of solid composite propellant,it is necessary to take measures to modify the thermal decomposition behavior of AP.In recent years,transition metal oxides and carbon-supported transition metal oxides have drawn considerable attention due to their extraordinary catalytic activity.In this review,we highlight strategies to enhance the thermal decomposition of AP by tuning morphology,varying the types of metal ion,and coupling with carbon analogue.The enhanced catalytic performance can be ascribed to synergistic effect,increased surface area,more exposed active sites,and accelerated electron transportation and so on.The mechanism of AP decomposition mixed with catalyst has also been briefly summarized.Finally,a conclusive outlook and possible research directions are suggested to address challenges such as lacking practical application in actual formulation of solid composite propellant and batch manufacturing.展开更多
Most of volatile organic compounds(VOCs)are harmful to the atmosphere and human health.Cata‐lytic combustion is an effective way to eliminate VOCs.The key issue is the availability of high per‐formance catalysts.Man...Most of volatile organic compounds(VOCs)are harmful to the atmosphere and human health.Cata‐lytic combustion is an effective way to eliminate VOCs.The key issue is the availability of high per‐formance catalysts.Many catalysts including transition metal oxides,mixed metal oxides,and sup‐ported noble metals have been developed.Among these catalysts,the porous ones attract much attention.In this review,we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides,perovskites,and supported noble metal catalysts and their catalytic oxidation of VOCs.The porous catalysts outperformed their bulk counterparts.This excel‐lent catalytic performance was due to their high surface areas,high concentration of adsorbed oxy‐gen species,low temperature reducibility,strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures.Catalytic oxidation of carbon monoxide over typical catalysts was also discussed.We made conclusive remarks and pro‐posed future work for the removal of VOCs.展开更多
g-C_(3)N_(4) emerges as a star 2D photocatalyst due to its unique layered structure,suitable band structure and low cost.However,its photocatalytic application is limited by the fast charge recombination and low photo...g-C_(3)N_(4) emerges as a star 2D photocatalyst due to its unique layered structure,suitable band structure and low cost.However,its photocatalytic application is limited by the fast charge recombination and low photoabsorption.Rationally designing g-C_(3)N_(4)-based heterojunction is promising for improving photocatalytic activity.Besides,g-C_(3)N_(4) exhibits great potentials in electrochemical energy storage.In view of the excellent performance of typical transition metal oxides(TMOs)in photocatalysis and energy storage,this review summarized the advances of TMOs/g-C_(3)N_(4) heterojunctions in the above two areas.Firstly,we introduce several typical TMOs based on their crystal structures and band structures.Then,we summarize different kinds of TMOs/g-C_(3)N_(4) heterojunctions,including type Ⅰ/Ⅱ heterojunction,Z-scheme,p-n junction and Schottky junction,with diverse photocatalytic applications(pollutant degradation,water splitting,CO_(2) reduction and N_(2) fixation)and supercapacitive energy storage.Finally,some promising strategies for improving the performance of TMOs/g-C_(3)N_(4) were proposed.Particularly,the exploration of photocatalysis-assisted supercapacitors was discussed.展开更多
In the past few years,the increasing energy consumption of traditional fossil fuels has posed a huge threat to human health.It is very imperious to develop the sustainable and renewable energy storage and conversion d...In the past few years,the increasing energy consumption of traditional fossil fuels has posed a huge threat to human health.It is very imperious to develop the sustainable and renewable energy storage and conversion devices with low cost and environment friendly features.Hybrid supercapacitors are eme rging as one of the promising energy devices with high power density,fast charge-discharge process and excellent cycle stability.However,morphology and structure of the electrode materials exert serious effect on their electrochemical performances.In this review,we summarized recent progresses in transition metal oxide based electrode materials for supercapacitors.Different synthesis routes and electrochemical performances of electrode materials and storage mechanisms of supercapacitor devices have been presented in details.The future developing trends of supercapacitor based on metal oxide electrode materials are also proposed.展开更多
As one of the most promising secondary batteries in large-scale energy storage,sodium ion batteries(SIBs) have attracted wide attention due to the abundant raw materials and low cost.Layered transition metal oxides ar...As one of the most promising secondary batteries in large-scale energy storage,sodium ion batteries(SIBs) have attracted wide attention due to the abundant raw materials and low cost.Layered transition metal oxides are one kind of popular cathode material candidates because of its easy synthesis and large theoretical specific capacity.Yet,the most common P2 and O3 phases show distinct structural characteristics respectively.O3 phase can serve as a sodium reservoir,but it usually suffers from serious phase transition and sluggish kinetics.For the P2 phase,it allows the fast sodium ion migration in the bulk and the structure can maintain stable,but it is lack of sodium,showing a great negative effect on Coulombic efficiency in full cell.Thus,single phase structure almost cannot achieve satisfied comprehensive sodium storage performances.Under these circumstances,exploiting novel multiphase cathodes showing synergetic effect may give solution to these problems.In this review,we summarize the recent development of multiphase layered transition metal oxide cathodes of SIBs,analyze the mechanism and prospect the future potential research directions.展开更多
Although CoO is a promising electrode material for supercapacitors due to its high theoretical capacitance,the practical applications still suffering from inferior electrochemical activity owing to its low electrical ...Although CoO is a promising electrode material for supercapacitors due to its high theoretical capacitance,the practical applications still suffering from inferior electrochemical activity owing to its low electrical conductivity,poor structural stability and inefficient nanostructure.Herein,we report a novel Cu0/Cu+co-doped CoO composite with adjustable metallic Cu0 and ion Cu+via a facile strategy.Through interior(Cu+)and exterior(Cu0)decoration of CoO,the electrochemical performance of CoO electrode has been significantly improved due to both the beneficial flower-like nanostructure and the synergetic effect of Cu0/Cu+co-doping,which results in a significantly enhanced specific capacitance(695 F g^(-1) at 1 A g^(-1))and high cyclic stability(93.4%retention over 10,000 cycles)than pristine CoO.Furthermore,this co-doping strategy is also applicable to other transition metal oxide(NiO)with enhanced electrochemical performance.In addition,an asymmetric hybrid supercapacitor was assembled using the Cu0/Cu+co-doped CoO electrode and active carbon,which delivers a remarkable maximal energy density(35 Wh kg^(-1)),exceptional power density(16 kW kg^(-1))and ultralong cycle life(91.5%retention over 10,000 cycles).Theoretical calculations further verify that the co-doping of Cu^(0)/Cu^(+)can tune the electronic structure of CoO and improve the conductivity and electron transport.This study demonstrates a facile and favorable strategy to enhance the electrochemical performance of transition metal oxide electrode materials.展开更多
Photoelectrochemical(PEC)water splitting can convert renewable solar energy into clean hydrogen fuel.Photoelectrodes are the core components of water-splitting cells.In the past 40 years,a series of binary and ternary...Photoelectrochemical(PEC)water splitting can convert renewable solar energy into clean hydrogen fuel.Photoelectrodes are the core components of water-splitting cells.In the past 40 years,a series of binary and ternary transition metal oxides have been investigated as photo-electrode materials for solar water splitting,and numerous studies have been carried out to modify their water-split-ting performances.Although satisfactory transition metal oxide photoelectrode materials have not been found,it is necessary to summarize the recent advancements in tran-sition metal oxide photoelectrode materials to guide future research.In this review,the background and principle of PEC water splitting are introduced.The semiconductor properties and modification progress of typical binary and ternary metal oxide photoanodes and photocathodes for solar water splitting are summarized.Based on the newly developed strategies in recent years,a brief outlook is presented for efficient PEC water splitting using transition metal oxide photoelectrodes.展开更多
Faraday pseudocapacitors take both advantages of secondary battery with high energy density and supercapacitors with high power density,and electrode material is the key to determine the performance of Faraday pseudoc...Faraday pseudocapacitors take both advantages of secondary battery with high energy density and supercapacitors with high power density,and electrode material is the key to determine the performance of Faraday pseudocapacitors.Transition metal oxides and nitrides,as the two main kinds of pseudocapacitor electrode materials,can enhance energy density while maintaining high power capability.Recent advances in designing nanostructured architectures and preparing composites with high specific surface areas based on transition metal oxides and nitrides,including ruthenium oxides,nickel oxides,manganese oxides,vanadium oxides,cobalt oxides,iridium oxides,titanium nitrides,vanadium nitrides,molybdenum nitrides and niobium nitrides,are addressed,which would provide important significances for deep researches on pseudocapacitor electrode materials.展开更多
Developing a new type of deep eutectic solvents(DESs)is indispensable for expanding their application in various fields.Here,we report a series of new highly basic DESs.FT-IR,quantitative 1 H NMR,MD simulation and phy...Developing a new type of deep eutectic solvents(DESs)is indispensable for expanding their application in various fields.Here,we report a series of new highly basic DESs.FT-IR,quantitative 1 H NMR,MD simulation and physical properties show that these basic liquids are made up of hydroxide acceptor of alkali metal hydroxides in which the hydrogen bonding interactions coordinate the donor.These DESs can be played three roles as new solvents,template and reactant for facile and ultra-fast preparation of transition metal oxide nanomaterials such as NiCo2 O4,MnCo2 O4,NiMn2 O4,CoCu2 O4 and Co3 O4 under mild condition.This work shows one of the low energy-intensive methods for nanomaterial preparation.These initial findings of basic deep eutectic solvents provide a potential applicability around the systematic development of transition metal oxide nanosheets.展开更多
This review provides insight into the current research trend in transition metal oxides(TMOs)-based photocatalysis in removing the organic colouring matters from water.For easy understanding,the research progress has ...This review provides insight into the current research trend in transition metal oxides(TMOs)-based photocatalysis in removing the organic colouring matters from water.For easy understanding,the research progress has been presented in four generations according to the catalyst composition and mode of application,viz:single component TMOs(the firstgeneration),doped TMOs/binary TMOs/doped binary TMOs(the second-generation),inactive/active support-immobilized TMOs(the third-generation),and ternary/quaternary compositions(the fourth-generation).The first two generations represent suspended catalysts,the third generation is supported catalysts,and the fourth generation can be suspended or supported.The review provides an elaborated comparison between suspended and supported catalysts,their general/specific requirements,key factors controlling degradation,and the methodologies for performance evaluation.All the plausible fundamental and advanced dye degradation mechanisms involved in each generation of catalysts were demonstrated.The existing challenges in TMOs-based photocatalysis and how the researchers approach the hitch to resolve it effectively are discussed.Future research trends are also presented.展开更多
The thermal conductivity of the mould fluxes containing transition metal oxides was measured by hotline method at different temperatures. The relationship between the thermal conductivity of mold fluxes and the conten...The thermal conductivity of the mould fluxes containing transition metal oxides was measured by hotline method at different temperatures. The relationship between the thermal conductivity of mold fluxes and the contents of transition metal oxides was discussed. The synthetic slags were composed of 30.0% - 35.4%CaO, 34.7% - 38.6% SiO2, 6% Al2O3, 9% Na2O, 14.4% CaF2, 0-4% Cr2O3 and 0-8% MnO in mass percent. The results indicated that Cr2O3 and MnO had a negative effect on thermal conductivity of mold fluxes. The thermal conductivity of mold fluxes was about 0.25-0.55 W/（m · K） when the temperature reached 1 300 ℃, and it increased sharply to about 1.32-1.99 W/（m · K） when the temperature reduced from 1300 to 1000 ℃. The thermal conductivity of mold fluxes containing Cr2 O3 and MnO was 10 %- 25% lower than those of original fluxes. The decrease in thermal conductivity was attributed to the change of molecular structure of mold fluxes. In addition, the poor integrity and regulation of polycrystal structure, complexity of crystal structure, and effects of impurities in the boundary and lat- tice distortion leaded to the reduction in the thermal conductivity. Na2 CrO4, Mn2 SiO4 and other minor phases were also found in the samples containing Cr2O3 and MnO, respectively.展开更多
Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of ex...Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materiaIs on electrochemical Li insertion/extraction performance was discussed. These two transition metal oxides belong to onegroup that the crystallinity of these oxides affects to the performance.展开更多
This paper systematically studies the reaction mechanisms of formic acid catalyzed by transition metal oxide MoO. Three different reaction pathways of Routes I, Ⅱ and Ⅲ were found through studying the reaction mecha...This paper systematically studies the reaction mechanisms of formic acid catalyzed by transition metal oxide MoO. Three different reaction pathways of Routes I, Ⅱ and Ⅲ were found through studying the reaction mechanism of transition metal oxide MoO catalyzing the formic acid. The transition metal oxide MoO interacts with the C=O double bond to form chiral chain compounds（Routes I and Ⅱ） and metallic compound MoOH2（Route Ⅲ）. In this paper, we have studied the mechanisms of two addition reaction pathways and hydrogen abstraction reaction pathway. Routes I and Ⅱ are both addition reactions, and their products are two different chiral compounds MoO3CH2, which are enantiomeric to each other. In Route Ⅲ, metal compounds MoOH2 and CO2 are obtained from the hydrogen abstraction reaction. Among them, the hydrogen abstraction reaction occurring in Route Ⅲ is more likely to occur than the others. By comparing the results of previous studies on the reaction of MxOy-＋ ROH（M= Mo,W; R = Me, Et）, we found that the hydrogen abstraction mechanism is completely different from the mechanism of oxygen-containing organic compound catalyzed by MxOy.展开更多
A serial of protonated and layered transition metal oxides, including layered HTaWO6, HNbMoO6 as well as HNbWO6, were synthesized by solid-state reaction and ion-exchange. The layered HTaWO6 has been systematically st...A serial of protonated and layered transition metal oxides, including layered HTaWO6, HNbMoO6 as well as HNbWO6, were synthesized by solid-state reaction and ion-exchange. The layered HTaWO6 has been systematically studied as a solid acid to realize the dehydration of fructose to 5-hydroxymethylfurfural (HMF). The transition metal oxide samples were characterized with ICP-OES, EDS, XRD, XPS, SEM, TGA, FT-IR, N-2 adsorption-desorption and NH3-TPD. The influential factors such as reaction temperature, reaction time, solvent, catalyst amount and substrate concentration were deeply investigated. The optimized fructose conversion rate of 99% with HMF yield of 67% were achieved after 30 min at 140 degrees C in dimethylsulfoxide. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
NF3 decomposition over transition metal oxides coated MgO reagents in the absence of water is investigated. The results show that NF3 can be decomposed completely over pure MgO but the time of NF3 steady full conversi...NF3 decomposition over transition metal oxides coated MgO reagents in the absence of water is investigated. The results show that NF3 can be decomposed completely over pure MgO but the time of NF3 steady full conversion kept as short as 80 min, while the reactivities of coated MgO reagents were remarkably enhanced by transition metal oxides, for example the time of NF3 complete conversion over 12%Fe/MgO extended to 380 min. It is suggested that not only an increase in surface area but also a significant enhancement in the fluorination of MgO substrate caused by the surface transition metal oxides result in an improved reactivity of coated MgO reagents for NF3 decomposition.展开更多
Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and...Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction pedermance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not; LiMn_2O_4 and LiCo_(0.5)O_2 belongs to the former group and TiO_2, V_2O_5 and MoO_3 to the latter.展开更多
文摘The labels of VU1 and VU2 in Fig.1(b)of the paper[Chin.Phys.B 34046801(2025)]were not correctly placed.The correct figure is provided.This modification does not affect the result presented in the paper.
基金financial support from the National Key Research&Development Program of China(Grant No.2023YFA1406500)the National Natural Science Foundation of China(Grant Nos.12104504,52461160327 and 92477205)the Fundamental Research Funds for the Central Universities,and the Research Funds of Renmin University of China[Grant Nos.22XNKJ30(W.J.)and 24XNKJ17(C.W.)]。
文摘Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhibit neat and well-defined kagome bands near the Fermi level,which are more easily realized in the absence of interlayer interactions.However,this absence also destabilizes the monolayer forms of many bulk kagome materials,posing significant challenges to their discovery.In this work,we propose a strategy to address this challenge by utilizing oxygen vacancies in transition metal oxides within a“1+3”design framework.Through high-throughput computational screening of 349 candidate materials,we identified 12 thermodynamically stable kagome monolayers with diverse electronic and magnetic properties.These materials were classified into three categories based on their lattice geometry,symmetry,band gaps,and magnetic configurations.Detailed analysis of three representative monolayers revealed kagome band features near their Fermi levels,with orbital contributions varying between oxygen 2p and transition metal d states.This study demonstrates the feasibility of the“1+3”strategy,offering a promising approach to uncovering low-dimensional kagome materials and advancing the exploration of their quantum phenomena.
基金supported by the National Natural Science Foundation of China(No.22273065)Shandong Energy institute(SEI U202312)"Strategic Priority Research Program"of the Chinese Academy of Sciences(No.XDA02020000).
文摘The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(2)(M=Ti,Zr,and Hf)compounds are formed in bent insertion structures.The observed ground-state adiabatic detachment energy(ADE)is measured to be 1.597±0.003,1.651±0.003,and 2.119±0.003 eV for TiO_(2)^(-),ZrO_(2)^(-),and HfO_(2)^(-),respectively.The vibrational frequencies of the anionic and neutral MO_(2)are also determined from the experimental spectra.The results of theoretical calculations show that the electronic configurations of MO_(2)^(-)are^(2)A_(1)with C_(2v)point group.Bond order analysis indicates that the two M-O bonds are all multiple characters.
基金supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(No.12034002)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities,No.FRF-IDRY-23-033)。
文摘Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.
基金This work was financially supported by the Science and Technology project of Jiangsu province(BN2015021,XZ-SZ201819).
文摘As a main oxidizer in solid composite propellants,ammonium perchlorate(AP)plays an important role because its thermal decomposition behavior has a direct influence on the characteristic of solid composite propellants.To improve the performance of solid composite propellant,it is necessary to take measures to modify the thermal decomposition behavior of AP.In recent years,transition metal oxides and carbon-supported transition metal oxides have drawn considerable attention due to their extraordinary catalytic activity.In this review,we highlight strategies to enhance the thermal decomposition of AP by tuning morphology,varying the types of metal ion,and coupling with carbon analogue.The enhanced catalytic performance can be ascribed to synergistic effect,increased surface area,more exposed active sites,and accelerated electron transportation and so on.The mechanism of AP decomposition mixed with catalyst has also been briefly summarized.Finally,a conclusive outlook and possible research directions are suggested to address challenges such as lacking practical application in actual formulation of solid composite propellant and batch manufacturing.
文摘Most of volatile organic compounds(VOCs)are harmful to the atmosphere and human health.Cata‐lytic combustion is an effective way to eliminate VOCs.The key issue is the availability of high per‐formance catalysts.Many catalysts including transition metal oxides,mixed metal oxides,and sup‐ported noble metals have been developed.Among these catalysts,the porous ones attract much attention.In this review,we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides,perovskites,and supported noble metal catalysts and their catalytic oxidation of VOCs.The porous catalysts outperformed their bulk counterparts.This excel‐lent catalytic performance was due to their high surface areas,high concentration of adsorbed oxy‐gen species,low temperature reducibility,strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures.Catalytic oxidation of carbon monoxide over typical catalysts was also discussed.We made conclusive remarks and pro‐posed future work for the removal of VOCs.
基金financially supported by the National Natural Science Foundation (No.52072347, 51972288, 51672258 and 51572246)the Fundamental Research Funds for the Central Universities (No. 2652019144 and 2652018287)+1 种基金the financial supports from the Science and Technology Program of Guangdong Province (2019A050510012)Shenzhen Science, Technology and Innovation Commission (SGDX2019081623240364).
文摘g-C_(3)N_(4) emerges as a star 2D photocatalyst due to its unique layered structure,suitable band structure and low cost.However,its photocatalytic application is limited by the fast charge recombination and low photoabsorption.Rationally designing g-C_(3)N_(4)-based heterojunction is promising for improving photocatalytic activity.Besides,g-C_(3)N_(4) exhibits great potentials in electrochemical energy storage.In view of the excellent performance of typical transition metal oxides(TMOs)in photocatalysis and energy storage,this review summarized the advances of TMOs/g-C_(3)N_(4) heterojunctions in the above two areas.Firstly,we introduce several typical TMOs based on their crystal structures and band structures.Then,we summarize different kinds of TMOs/g-C_(3)N_(4) heterojunctions,including type Ⅰ/Ⅱ heterojunction,Z-scheme,p-n junction and Schottky junction,with diverse photocatalytic applications(pollutant degradation,water splitting,CO_(2) reduction and N_(2) fixation)and supercapacitive energy storage.Finally,some promising strategies for improving the performance of TMOs/g-C_(3)N_(4) were proposed.Particularly,the exploration of photocatalysis-assisted supercapacitors was discussed.
基金supported by Education Department Funding of Liaoning Province(No.LJGD2019001)Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technology(No.191010-K)Guangxi Key Laboratory of Electrochemical Energy Materials(No.2019001)。
文摘In the past few years,the increasing energy consumption of traditional fossil fuels has posed a huge threat to human health.It is very imperious to develop the sustainable and renewable energy storage and conversion devices with low cost and environment friendly features.Hybrid supercapacitors are eme rging as one of the promising energy devices with high power density,fast charge-discharge process and excellent cycle stability.However,morphology and structure of the electrode materials exert serious effect on their electrochemical performances.In this review,we summarized recent progresses in transition metal oxide based electrode materials for supercapacitors.Different synthesis routes and electrochemical performances of electrode materials and storage mechanisms of supercapacitor devices have been presented in details.The future developing trends of supercapacitor based on metal oxide electrode materials are also proposed.
基金financial support from the National Key R&D Program of China(No.2018YFB0104300)National Natural Science Foundation of China(Nos.21633003,51802149 and U1801251)+1 种基金NSF of Jiangsu Province,China(No.BK20170630)the Fundamental Research Funds for the Central Universities(Nos.021314380141 and 021314380157)。
文摘As one of the most promising secondary batteries in large-scale energy storage,sodium ion batteries(SIBs) have attracted wide attention due to the abundant raw materials and low cost.Layered transition metal oxides are one kind of popular cathode material candidates because of its easy synthesis and large theoretical specific capacity.Yet,the most common P2 and O3 phases show distinct structural characteristics respectively.O3 phase can serve as a sodium reservoir,but it usually suffers from serious phase transition and sluggish kinetics.For the P2 phase,it allows the fast sodium ion migration in the bulk and the structure can maintain stable,but it is lack of sodium,showing a great negative effect on Coulombic efficiency in full cell.Thus,single phase structure almost cannot achieve satisfied comprehensive sodium storage performances.Under these circumstances,exploiting novel multiphase cathodes showing synergetic effect may give solution to these problems.In this review,we summarize the recent development of multiphase layered transition metal oxide cathodes of SIBs,analyze the mechanism and prospect the future potential research directions.
基金financially supported by the National Science Foundation of China(Grant No.11804106)。
文摘Although CoO is a promising electrode material for supercapacitors due to its high theoretical capacitance,the practical applications still suffering from inferior electrochemical activity owing to its low electrical conductivity,poor structural stability and inefficient nanostructure.Herein,we report a novel Cu0/Cu+co-doped CoO composite with adjustable metallic Cu0 and ion Cu+via a facile strategy.Through interior(Cu+)and exterior(Cu0)decoration of CoO,the electrochemical performance of CoO electrode has been significantly improved due to both the beneficial flower-like nanostructure and the synergetic effect of Cu0/Cu+co-doping,which results in a significantly enhanced specific capacitance(695 F g^(-1) at 1 A g^(-1))and high cyclic stability(93.4%retention over 10,000 cycles)than pristine CoO.Furthermore,this co-doping strategy is also applicable to other transition metal oxide(NiO)with enhanced electrochemical performance.In addition,an asymmetric hybrid supercapacitor was assembled using the Cu0/Cu+co-doped CoO electrode and active carbon,which delivers a remarkable maximal energy density(35 Wh kg^(-1)),exceptional power density(16 kW kg^(-1))and ultralong cycle life(91.5%retention over 10,000 cycles).Theoretical calculations further verify that the co-doping of Cu^(0)/Cu^(+)can tune the electronic structure of CoO and improve the conductivity and electron transport.This study demonstrates a facile and favorable strategy to enhance the electrochemical performance of transition metal oxide electrode materials.
基金financially supported by the National Key R&D Program of China (No. 2018YFE0208500)the National Natural Science Foundation of China (No. 41702037)
文摘Photoelectrochemical(PEC)water splitting can convert renewable solar energy into clean hydrogen fuel.Photoelectrodes are the core components of water-splitting cells.In the past 40 years,a series of binary and ternary transition metal oxides have been investigated as photo-electrode materials for solar water splitting,and numerous studies have been carried out to modify their water-split-ting performances.Although satisfactory transition metal oxide photoelectrode materials have not been found,it is necessary to summarize the recent advancements in tran-sition metal oxide photoelectrode materials to guide future research.In this review,the background and principle of PEC water splitting are introduced.The semiconductor properties and modification progress of typical binary and ternary metal oxide photoanodes and photocathodes for solar water splitting are summarized.Based on the newly developed strategies in recent years,a brief outlook is presented for efficient PEC water splitting using transition metal oxide photoelectrodes.
基金Project(51274248) supported by the National Natural Science Foundation of ChinaProjects(2015DFR50580,2013DFA31440) supported by the International Scientific and Technological Cooperation Projects of China
文摘Faraday pseudocapacitors take both advantages of secondary battery with high energy density and supercapacitors with high power density,and electrode material is the key to determine the performance of Faraday pseudocapacitors.Transition metal oxides and nitrides,as the two main kinds of pseudocapacitor electrode materials,can enhance energy density while maintaining high power capability.Recent advances in designing nanostructured architectures and preparing composites with high specific surface areas based on transition metal oxides and nitrides,including ruthenium oxides,nickel oxides,manganese oxides,vanadium oxides,cobalt oxides,iridium oxides,titanium nitrides,vanadium nitrides,molybdenum nitrides and niobium nitrides,are addressed,which would provide important significances for deep researches on pseudocapacitor electrode materials.
基金supported by the National Natural Science Foundation of China(Nos.21822407,21675164)the CASPresident International Fellowship Initiative(No.2017PC0014)。
文摘Developing a new type of deep eutectic solvents(DESs)is indispensable for expanding their application in various fields.Here,we report a series of new highly basic DESs.FT-IR,quantitative 1 H NMR,MD simulation and physical properties show that these basic liquids are made up of hydroxide acceptor of alkali metal hydroxides in which the hydrogen bonding interactions coordinate the donor.These DESs can be played three roles as new solvents,template and reactant for facile and ultra-fast preparation of transition metal oxide nanomaterials such as NiCo2 O4,MnCo2 O4,NiMn2 O4,CoCu2 O4 and Co3 O4 under mild condition.This work shows one of the low energy-intensive methods for nanomaterial preparation.These initial findings of basic deep eutectic solvents provide a potential applicability around the systematic development of transition metal oxide nanosheets.
基金supporting us by providing technical facilities(access to journals)。
文摘This review provides insight into the current research trend in transition metal oxides(TMOs)-based photocatalysis in removing the organic colouring matters from water.For easy understanding,the research progress has been presented in four generations according to the catalyst composition and mode of application,viz:single component TMOs(the firstgeneration),doped TMOs/binary TMOs/doped binary TMOs(the second-generation),inactive/active support-immobilized TMOs(the third-generation),and ternary/quaternary compositions(the fourth-generation).The first two generations represent suspended catalysts,the third generation is supported catalysts,and the fourth generation can be suspended or supported.The review provides an elaborated comparison between suspended and supported catalysts,their general/specific requirements,key factors controlling degradation,and the methodologies for performance evaluation.All the plausible fundamental and advanced dye degradation mechanisms involved in each generation of catalysts were demonstrated.The existing challenges in TMOs-based photocatalysis and how the researchers approach the hitch to resolve it effectively are discussed.Future research trends are also presented.
基金Sponsored by Doctor Programs Foundation of Education Ministry of China(200806110006)
文摘The thermal conductivity of the mould fluxes containing transition metal oxides was measured by hotline method at different temperatures. The relationship between the thermal conductivity of mold fluxes and the contents of transition metal oxides was discussed. The synthetic slags were composed of 30.0% - 35.4%CaO, 34.7% - 38.6% SiO2, 6% Al2O3, 9% Na2O, 14.4% CaF2, 0-4% Cr2O3 and 0-8% MnO in mass percent. The results indicated that Cr2O3 and MnO had a negative effect on thermal conductivity of mold fluxes. The thermal conductivity of mold fluxes was about 0.25-0.55 W/（m · K） when the temperature reached 1 300 ℃, and it increased sharply to about 1.32-1.99 W/（m · K） when the temperature reduced from 1300 to 1000 ℃. The thermal conductivity of mold fluxes containing Cr2 O3 and MnO was 10 %- 25% lower than those of original fluxes. The decrease in thermal conductivity was attributed to the change of molecular structure of mold fluxes. In addition, the poor integrity and regulation of polycrystal structure, complexity of crystal structure, and effects of impurities in the boundary and lat- tice distortion leaded to the reduction in the thermal conductivity. Na2 CrO4, Mn2 SiO4 and other minor phases were also found in the samples containing Cr2O3 and MnO, respectively.
文摘Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materiaIs on electrochemical Li insertion/extraction performance was discussed. These two transition metal oxides belong to onegroup that the crystallinity of these oxides affects to the performance.
基金supported by the National Natural Science Foundation of China(No.21373025)the major project of Tangshan Normal College(No.2017B01)
文摘This paper systematically studies the reaction mechanisms of formic acid catalyzed by transition metal oxide MoO. Three different reaction pathways of Routes I, Ⅱ and Ⅲ were found through studying the reaction mechanism of transition metal oxide MoO catalyzing the formic acid. The transition metal oxide MoO interacts with the C=O double bond to form chiral chain compounds（Routes I and Ⅱ） and metallic compound MoOH2（Route Ⅲ）. In this paper, we have studied the mechanisms of two addition reaction pathways and hydrogen abstraction reaction pathway. Routes I and Ⅱ are both addition reactions, and their products are two different chiral compounds MoO3CH2, which are enantiomeric to each other. In Route Ⅲ, metal compounds MoOH2 and CO2 are obtained from the hydrogen abstraction reaction. Among them, the hydrogen abstraction reaction occurring in Route Ⅲ is more likely to occur than the others. By comparing the results of previous studies on the reaction of MxOy-＋ ROH（M= Mo,W; R = Me, Et）, we found that the hydrogen abstraction mechanism is completely different from the mechanism of oxygen-containing organic compound catalyzed by MxOy.
基金supported by the National Natural Science Foundation of China (21472189)National Basic Research Program of China (973 Program, 2012CB215304)+2 种基金the Natural Science Foundation of Guangdong Province, China (2015A030312007)Guangdong Key Laboratory of New and Renewable Energy Research and Development (Y607jl1001)Science and Technology Planning Project of Guangdong Province, China (2015A010106010)
文摘A serial of protonated and layered transition metal oxides, including layered HTaWO6, HNbMoO6 as well as HNbWO6, were synthesized by solid-state reaction and ion-exchange. The layered HTaWO6 has been systematically studied as a solid acid to realize the dehydration of fructose to 5-hydroxymethylfurfural (HMF). The transition metal oxide samples were characterized with ICP-OES, EDS, XRD, XPS, SEM, TGA, FT-IR, N-2 adsorption-desorption and NH3-TPD. The influential factors such as reaction temperature, reaction time, solvent, catalyst amount and substrate concentration were deeply investigated. The optimized fructose conversion rate of 99% with HMF yield of 67% were achieved after 30 min at 140 degrees C in dimethylsulfoxide. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金financially supported by the National Natural Science Foundation of China(No.20976149)
文摘NF3 decomposition over transition metal oxides coated MgO reagents in the absence of water is investigated. The results show that NF3 can be decomposed completely over pure MgO but the time of NF3 steady full conversion kept as short as 80 min, while the reactivities of coated MgO reagents were remarkably enhanced by transition metal oxides, for example the time of NF3 complete conversion over 12%Fe/MgO extended to 380 min. It is suggested that not only an increase in surface area but also a significant enhancement in the fluorination of MgO substrate caused by the surface transition metal oxides result in an improved reactivity of coated MgO reagents for NF3 decomposition.
文摘Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction pedermance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not; LiMn_2O_4 and LiCo_(0.5)O_2 belongs to the former group and TiO_2, V_2O_5 and MoO_3 to the latter.
