Oxygen evolution reaction(OER),as an important half‐reaction involved in water splitting,has been intensely studied since the last century.Transition metal phosphide and sulfide‐based compounds have attracted increa...Oxygen evolution reaction(OER),as an important half‐reaction involved in water splitting,has been intensely studied since the last century.Transition metal phosphide and sulfide‐based compounds have attracted increasing attention as active OER catalysts due to their excellent physical and chemical characters,and massive efforts have been devoted to improving the phosphide and sulfide‐based materials with better activity and stability in recent years.In this review,the recent progress on phosphide and sulfide‐based OER electrocatalysts in terms of chemical properties,synthetic methodologies,catalytic performances evaluation and improvement strategy is reviewed.The most accepted reaction pathways as well as the thermodynamics and electrochemistry of the OER are firstly introduced in brief,followed by a summary of the recent research and optimization strategy of phosphide and sulfide‐based OER electrocatalysts.Finally,some mechanistic studies of the active phase of phosphide and sulfide‐based compounds are discussed to give insight into the nature of active catalytic sites.It is expected to indicate guidance for further improving the performances of phosphide and sulfide‐based OER electrocatalysts.展开更多
With the goal of constructing a carbon‐free energy cycle,proton‐exchange membrane(PEM)water electrolysis is a promising technology that can be integrated effectively with renewable energy resources to produce high‐...With the goal of constructing a carbon‐free energy cycle,proton‐exchange membrane(PEM)water electrolysis is a promising technology that can be integrated effectively with renewable energy resources to produce high‐purity hydrogen.IrO2,as a commercial electrocatalyst for the anode side of a PEM water electrolyzer,can both overcome the high corrosion conditions and exhibit efficient catalytic performance.However,the high consumption of Ir species cannot meet the sustainable development and economic requirements of this technology.Accordingly,it is necessary to understand the OER catalytic mechanisms for Ir species,further designing new types of low‐iridium catalysts with high activity and stability to replace IrO2.In this review,we first summarize the related catalytic mechanisms of the acidic oxygen evolution reaction(OER),and then provide general methods for measuring the catalytic performance of materials.Second,we present the structural evolution results of crystalline IrO2 and amorphous IrOx using in situ characterization techniques under catalytic conditions to understand the common catalytic characteristics of the materials and the possible factors affecting the structural evolution characteristics.Furthermore,we focus on three types of common low‐iridium catalysts,including heteroatom‐doped IrO2(IrOx)‐based catalysts,perovskite‐type iridium‐based catalysts,and pyrochlore‐type iridium‐based catalysts,and try to correlate the structural features with the intrinsic catalytic performance of materials.Finally,at the end of the review,we present the unresolved problems and challenges in this field in an attempt to develop effective strategies to further balance the catalytic activity and stability of materials under acidic OER catalytic conditions.展开更多
Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and ...Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and low intrinsic activity limit their practical application.To date,improvement of the intrinsic activity and stability of NiFe-LDHs through the introduction of heteroatoms or its combination with other conductive substrates to enhance their water-splitting performance has drawn increasing attention.In this study,vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes(NiFe P/MXene)were successfully synthesised through a hydrothermal reaction and phosphating calcination process.The optimised NiFe P/MXene exhibited a low overpotential of 286 m V at 10 m A cm^(-2) and a Tafel slope of 35 m V dec^(-1) for the OER,which exceeded the performance of several existing NiFe-based catalysts.NiFe P/MXene was further used as a water-splitting anode in an alkaline electrolyte,exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 m A cm^(-2).Density functional theory(DFT)calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to promote the energy level of the d-band centre,resulting in an enhanced OER performance.This study provides a valuable guideline for designing high-performance MXenesupported NiFe-based OER catalysts.展开更多
The generation of hydrogen through the electrolysis of water has attracted attention as a promising way to produce and store energy using renewable energy sources.In this process,a catalyst is very important to achiev...The generation of hydrogen through the electrolysis of water has attracted attention as a promising way to produce and store energy using renewable energy sources.In this process,a catalyst is very important to achieve a high‐energy conversion efficiency for the electrolysis of water.A good catalyst for water electrolysis should exhibit high catalytic activity,good stability,low cost and good scalability.Much research has been devoted to developing efficient catalysts for both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Traditionally,it has been accepted that a material with high crystallinity is important to serve as a good catalyst for HER and/or OER.Recently,catalysts for HER and/or OER in the electrolysis of water splitting based on amorphous materials have received much interest in the scientific community owing to the abundant unsaturated active sites on the amorphous surface,which form catalytic centers for the reaction of the electrolysis of water.We summarize the recent advances of amorphous catalysts for HER,OER and overall water splitting by electrolysis and the related fundamental chemical reactions involved in the electrolysis of water.The current challenges confronting the electrolysis of water and the development of more efficient amorphous catalysts are also discussed.展开更多
Two-dimensional(2D)metal-organic frameworks(MOFs)are promising for electrocatalysis with high performance,as they possess large surface areas and high densities of exposed active sites.It attracts tremendous attention...Two-dimensional(2D)metal-organic frameworks(MOFs)are promising for electrocatalysis with high performance,as they possess large surface areas and high densities of exposed active sites.It attracts tremendous attention to obtain 2D nanostructures via simple preparation methods.Herein,a facile pyridine-modulated solvothermal synthesis of Ni/Co bimetallic MOF nanoplates(NixCoy-bpy(PyM))is reported with well-defined 2D morphology with a thickness as thin as 20 nm and an aspect ratio larger than 50.These nanoplates possess oxygen evolution reaction activity as electrocatalysts in alkaline conditions.Specifically,Ni0.5Co1.5-bpy(PyM)exhibits excellent OER electrocatalytic activity with a low overpotential of 256 mV at 10 m A cm-2 and a small Tafel slope of 81.8 mV dec-1 in 1.0 mol L-1 KOH with long-term electrochemical stability for 3000 cyclic voltammetry cycles.The high catalytic activity of Ni0.5Co1.5-bpy(PyM)can be attributed to the in situ formed active hydroxide and oxyhydroxide species within the inherited 2D morphology and the optimized bimetallic ratio.展开更多
It is a great challenge to develop highly active oxygen evolution reaction(OER)electrocatalysts with superior durability.In this study,a NiFe layered double hydroxidedecorated phosphide(NiFe LDH@CoP/NiP_(3))was constr...It is a great challenge to develop highly active oxygen evolution reaction(OER)electrocatalysts with superior durability.In this study,a NiFe layered double hydroxidedecorated phosphide(NiFe LDH@CoP/NiP_(3))was constructed to display satisfactory OER activity and good stability for water splitting in alkaline media.At an overpotential of 300 mV,NiFe LDH@CoP/NiP_(3) achieved a current density of 82 mA cm^(-2) for the OER,which was 9.1 and 2.3 times that of CoP/NiP_(3) and NiFe LDH,respectively.Moreover,the reconstruction behavior,during which oxyhydroxides formed,was studied by a combination of X-ray photoelectron spectroscopy,Raman spectroscopy,and scanning electron microscopy.A synergistic effect between NiFe LDH and CoP/NiP_(3) was also observed for the hydrogen evolution reaction.Furthermore,when NiFe LDH@CoP/NiP_(3) acted as both the cathode and anode for overall water splitting,a high current density of 100 mA cm^(-2) was maintained for more than 275 h.In addition,under Xe light irradiation,a solar-to-hydrogen efficiency of 9.89% was achieved for solar-driven water splitting.This work presents the coupling of different active compositions,and can provide a reference for designing bifunctional electrocatalysts.展开更多
文摘Oxygen evolution reaction(OER),as an important half‐reaction involved in water splitting,has been intensely studied since the last century.Transition metal phosphide and sulfide‐based compounds have attracted increasing attention as active OER catalysts due to their excellent physical and chemical characters,and massive efforts have been devoted to improving the phosphide and sulfide‐based materials with better activity and stability in recent years.In this review,the recent progress on phosphide and sulfide‐based OER electrocatalysts in terms of chemical properties,synthetic methodologies,catalytic performances evaluation and improvement strategy is reviewed.The most accepted reaction pathways as well as the thermodynamics and electrochemistry of the OER are firstly introduced in brief,followed by a summary of the recent research and optimization strategy of phosphide and sulfide‐based OER electrocatalysts.Finally,some mechanistic studies of the active phase of phosphide and sulfide‐based compounds are discussed to give insight into the nature of active catalytic sites.It is expected to indicate guidance for further improving the performances of phosphide and sulfide‐based OER electrocatalysts.
文摘With the goal of constructing a carbon‐free energy cycle,proton‐exchange membrane(PEM)water electrolysis is a promising technology that can be integrated effectively with renewable energy resources to produce high‐purity hydrogen.IrO2,as a commercial electrocatalyst for the anode side of a PEM water electrolyzer,can both overcome the high corrosion conditions and exhibit efficient catalytic performance.However,the high consumption of Ir species cannot meet the sustainable development and economic requirements of this technology.Accordingly,it is necessary to understand the OER catalytic mechanisms for Ir species,further designing new types of low‐iridium catalysts with high activity and stability to replace IrO2.In this review,we first summarize the related catalytic mechanisms of the acidic oxygen evolution reaction(OER),and then provide general methods for measuring the catalytic performance of materials.Second,we present the structural evolution results of crystalline IrO2 and amorphous IrOx using in situ characterization techniques under catalytic conditions to understand the common catalytic characteristics of the materials and the possible factors affecting the structural evolution characteristics.Furthermore,we focus on three types of common low‐iridium catalysts,including heteroatom‐doped IrO2(IrOx)‐based catalysts,perovskite‐type iridium‐based catalysts,and pyrochlore‐type iridium‐based catalysts,and try to correlate the structural features with the intrinsic catalytic performance of materials.Finally,at the end of the review,we present the unresolved problems and challenges in this field in an attempt to develop effective strategies to further balance the catalytic activity and stability of materials under acidic OER catalytic conditions.
基金supported by the National Natural Science Foundation of China(21875048)the Outstanding Youth Project of Guangdong Natural Science Foundation(2020B1515020028)+1 种基金the Yangcheng Scholars Research Project of Guangzhou(201831820)the Science and Technology Research Project of Guangzhou(202002010007)。
文摘Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and low intrinsic activity limit their practical application.To date,improvement of the intrinsic activity and stability of NiFe-LDHs through the introduction of heteroatoms or its combination with other conductive substrates to enhance their water-splitting performance has drawn increasing attention.In this study,vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes(NiFe P/MXene)were successfully synthesised through a hydrothermal reaction and phosphating calcination process.The optimised NiFe P/MXene exhibited a low overpotential of 286 m V at 10 m A cm^(-2) and a Tafel slope of 35 m V dec^(-1) for the OER,which exceeded the performance of several existing NiFe-based catalysts.NiFe P/MXene was further used as a water-splitting anode in an alkaline electrolyte,exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 m A cm^(-2).Density functional theory(DFT)calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to promote the energy level of the d-band centre,resulting in an enhanced OER performance.This study provides a valuable guideline for designing high-performance MXenesupported NiFe-based OER catalysts.
基金the financial support from Chinese Scholarship Council (CSC)the support from Australian Research Council (ARC) Future Fellowship scheme
文摘The generation of hydrogen through the electrolysis of water has attracted attention as a promising way to produce and store energy using renewable energy sources.In this process,a catalyst is very important to achieve a high‐energy conversion efficiency for the electrolysis of water.A good catalyst for water electrolysis should exhibit high catalytic activity,good stability,low cost and good scalability.Much research has been devoted to developing efficient catalysts for both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Traditionally,it has been accepted that a material with high crystallinity is important to serve as a good catalyst for HER and/or OER.Recently,catalysts for HER and/or OER in the electrolysis of water splitting based on amorphous materials have received much interest in the scientific community owing to the abundant unsaturated active sites on the amorphous surface,which form catalytic centers for the reaction of the electrolysis of water.We summarize the recent advances of amorphous catalysts for HER,OER and overall water splitting by electrolysis and the related fundamental chemical reactions involved in the electrolysis of water.The current challenges confronting the electrolysis of water and the development of more efficient amorphous catalysts are also discussed.
基金supported by the National Natural Science Foundation of China(U1904215,21671170 and 21875207)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)+4 种基金the Program for New Century Excellent Talents of the University in China(NCET-13-0645)the Six Talent Plan(2015XCL-030)Qinglan Projectthe Priority Academic Program Development of Jiangsu Higher Education Institutionsthe support from the postdoctoral fund of Yangzhou University。
文摘Two-dimensional(2D)metal-organic frameworks(MOFs)are promising for electrocatalysis with high performance,as they possess large surface areas and high densities of exposed active sites.It attracts tremendous attention to obtain 2D nanostructures via simple preparation methods.Herein,a facile pyridine-modulated solvothermal synthesis of Ni/Co bimetallic MOF nanoplates(NixCoy-bpy(PyM))is reported with well-defined 2D morphology with a thickness as thin as 20 nm and an aspect ratio larger than 50.These nanoplates possess oxygen evolution reaction activity as electrocatalysts in alkaline conditions.Specifically,Ni0.5Co1.5-bpy(PyM)exhibits excellent OER electrocatalytic activity with a low overpotential of 256 mV at 10 m A cm-2 and a small Tafel slope of 81.8 mV dec-1 in 1.0 mol L-1 KOH with long-term electrochemical stability for 3000 cyclic voltammetry cycles.The high catalytic activity of Ni0.5Co1.5-bpy(PyM)can be attributed to the in situ formed active hydroxide and oxyhydroxide species within the inherited 2D morphology and the optimized bimetallic ratio.
基金financially supported by Hunan Provincial Science and Technology Plan Project(2017TP1001 and2020JJ4710)the National Key R&D Program of China(2018YFB0704100)the State Key Laboratory Fund。
文摘It is a great challenge to develop highly active oxygen evolution reaction(OER)electrocatalysts with superior durability.In this study,a NiFe layered double hydroxidedecorated phosphide(NiFe LDH@CoP/NiP_(3))was constructed to display satisfactory OER activity and good stability for water splitting in alkaline media.At an overpotential of 300 mV,NiFe LDH@CoP/NiP_(3) achieved a current density of 82 mA cm^(-2) for the OER,which was 9.1 and 2.3 times that of CoP/NiP_(3) and NiFe LDH,respectively.Moreover,the reconstruction behavior,during which oxyhydroxides formed,was studied by a combination of X-ray photoelectron spectroscopy,Raman spectroscopy,and scanning electron microscopy.A synergistic effect between NiFe LDH and CoP/NiP_(3) was also observed for the hydrogen evolution reaction.Furthermore,when NiFe LDH@CoP/NiP_(3) acted as both the cathode and anode for overall water splitting,a high current density of 100 mA cm^(-2) was maintained for more than 275 h.In addition,under Xe light irradiation,a solar-to-hydrogen efficiency of 9.89% was achieved for solar-driven water splitting.This work presents the coupling of different active compositions,and can provide a reference for designing bifunctional electrocatalysts.
