Water splitting powered by clean electricity is a sustainable and promising approach to produce green hydrogen.Currently,noble metal(e.g.Iridium,Ruthenium,Platinum)-based catalysts are most widely used for water split...Water splitting powered by clean electricity is a sustainable and promising approach to produce green hydrogen.Currently,noble metal(e.g.Iridium,Ruthenium,Platinum)-based catalysts are most widely used for water splitting electrolysis.However,noble metal-based catalysts often suffer from multiple disadvantages,including high cost,low selectivity and poor durability.The emergence of metal-organic framework nanosheets(MOFNSs)attracts significant attention due to their unique advantages.Here,a concise,yet comprehensive and critical,review of recent advances in the field of MOFNSs is provided.This review explains the fundamental oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)catalytic mechanisms as well as key characterization techniques for the structure-activity relationship study are discussed.Moreover,it discusses efficient design strategies and the brief research advances of MOFNSs in HER,OER,and bifunctional electrocatalysis,along with some challenges and opportunities.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
The large‐scale application of proton exchange membrane water electrolysis technology requires the development of high‐performance oxygen evolution electrocatalysts with as little iridium(Ir)as possible.Ir‐based do...The large‐scale application of proton exchange membrane water electrolysis technology requires the development of high‐performance oxygen evolution electrocatalysts with as little iridium(Ir)as possible.Ir‐based double perovskite oxides(A_(2)B’IrO_(6);A=alkaline,alkaline‐earth,or rare‐earth elements;B’=transition metal or rare‐earth elements)represent a class of oxides with great potential to replace the commercial catalyst IrO_(2).However,the structural evolution of Ir‐based double perovskite oxides in electrolytes is incompletely understood,and foundational knowledge of the design principle of the“ideal”material is lacking.In this work,we report the unexpected phenomenon of instant Ir leaching from Ir‐based double perovskite oxides in acid under non‐catalytic conditions and discuss the implications of this phenomenon for mechanism investigation and material identification.Some well‐known Ir‐based double perovskite oxides,such as Ba_(2)PrIrO_(6) and Sr_(2)YIrO_(6),undergo instantaneous Ir leaching when they come into contact with acidic electrolytes.The Ir‐leaching process is found to be non‐persistent and non‐thermodynamically determined,and its extent is correlated with the leaching of other B’‐site elements in the perovskite oxides.Based on this observation,we revisit the Ir dissolution‐precipitation process for surface IrO_(x) formation during the perovskite‐electrolyzed oxygen evolution reaction,emphasizing the non‐negligible role of Ir species owing to acid corrosion in the electrolyte.Finally,we modify a screening protocol for low‐Ir oxygen evolution electrocatalysts and propose an instant acid corrosion test as an indispensable process to evaluate the structural stability of potential 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
An efficient and economical oxygen evolution reaction(OER)catalyst is critical to the widespread application of solar energy to fuel conversion.Among many potential OER catalysts,the metal oxyhydroxides,especially FeO...An efficient and economical oxygen evolution reaction(OER)catalyst is critical to the widespread application of solar energy to fuel conversion.Among many potential OER catalysts,the metal oxyhydroxides,especially FeOOH,show promising OER reactivity.In the present work,we performed a DFT+U study of the OER mechanism on theγ‐FeOOH(010)surface.In particular,we established the chemical potential of the OH?and hole pair and included the OH?anion in the reaction pathway,accounting to the alkaline conditions of anodic OER process.We then analyzed the OER pathways on the surface with OH‐,O‐and Fe‐terminations.On the surface with OH‐and O‐terminations,the O2molecule could form from either OH reacting with the surface oxygen species(-OH*and-O*)or the combination of two surface oxygen species.On the Fe‐terminated surface,O2can only form by adsorbing OH on the Fe sites first.The potential‐limiting step of the oxygen evolution with different surface terminations was determined by following the free‐energy change of the elementary steps along each pathway.Our results show that oxygen formation requires recreating the surface Fe sites,and consequently,the condition that favors the partially exposed Fe sites will promote oxygen formation.展开更多
Efficient and stable bifunctional electrocatalysts for water splitting is essential for producing hydrogen and alleviating huge energy consumption.Meanwhile,charge transfer engineering is an efficient approach to modu...Efficient and stable bifunctional electrocatalysts for water splitting is essential for producing hydrogen and alleviating huge energy consumption.Meanwhile,charge transfer engineering is an efficient approach to modulate the localized electronic properties of catalysts and tune the electrocatalytic performance.Herein,we tactfully fabricate PtFeNi alloys/NiFe layered double hydroxides(LDHs)heterostructure by an easily electrochemical way with a small amount of Pt.The experimental and theoretical results unravel that the charge transfer on the alloy clusters modulated by the defective substrates(NiFe LDHs),which synergistically optimizes the adsorption energy of the reaction intermediates.The electrocatalyst exhibits an ultra‐low overpotential of 81 and 243 mV at the current density of 100 mA cm^(–2) for hydrogen evolution and oxygen evolution,respectively.Furthermore,the overall water splitting indicates that PtFeNi alloys/NiFe LDHs presents an ultra‐low overpotential of 265 and 406 mV to reach the current density of 10 and 300 mA cm^(–2),respectively.It proves that the PtFeNi alloys/NiFe LDHs catalyst is an excellent dual‐function electrocatalyst for water splitting and promising for industrialization.This work provides a new electrochemical approach to construct the alloy heterostructure.The prepared heterostructures act as an ideal platform to investigate the charge re‐distribution behavior and to improve the electrocatalytic activity.展开更多
Catalytic water splitting potentially reduce the consumption of fossil fuels and has received intense research attention.Synergy effects in multi‐element transition metal‐based water splitting catalysts have evoked ...Catalytic water splitting potentially reduce the consumption of fossil fuels and has received intense research attention.Synergy effects in multi‐element transition metal‐based water splitting catalysts have evoked special interests.Studies on catalysts in interfacial structures are especially meaningful due to their pertinence in applications.In this study,we report the synergy effects in promoting catalytic power in the ternary transition metal Zn,Co,Ni alloy nanoparticles that embeds in the carbonized Ppy/CNT multilayered matrix.By comparison with a series of binary or single metal counterparts,the mechanism under the synergy effects are elucidated.Experimental and DFT calculation results indicate that the ternary transition metal catalysts in the N‐doped carbon matrix present special electronic structure,which benefits the reversible transition‐state adsorption in HER and OER and render the catalysts high conductivity in room temperature.We expect our findings inspire further development of efficient transition metal HER and OER catalysts.展开更多
As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this issue.Herein...As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this issue.Herein,we successfully fabricated a three-dimensional iron-dysprosium oxide co-regulated in-situ formed MOF-Ni arrays on carbon cloth(FeDy@MOF-Ni/CC)through a facile two-step hydrothermal method.Electrochemical studies demonstrate that the designed FeDy@MOF-Ni/CC catalyst requires an overpotential of only 251 mV to reach 10 mA cm-2 with a small Tafel slope of 52.1 mV dec-1.Additionally,the stability declined by only 5.5%after 80 h of continuous testing in 1.0 M KOH.Furthermore,a cell voltage of only 1.57 V in the overall water splitting system is sufficient to achieve 10 mA cm-2;this value is far better than that of most previously reported catalysts.The excellent catalytic performance originates from the unique 3D rhombus-like structure,as well as coupling synergies of Fe-Dy-Ni species.The combination of lanthanide and transition metal species in the synthesis strategy may open entirely new possibilities with promising potential in the design of highly active OER electrocatalysts.展开更多
Although the intermittent energy-driven direct seawater splitting technology provides an unparalleled approach to achieving sustainable development,the severe corrosion via aggressive Cl^(-)severely affects the stabil...Although the intermittent energy-driven direct seawater splitting technology provides an unparalleled approach to achieving sustainable development,the severe corrosion via aggressive Cl^(-)severely affects the stability and efficiency of the anode catalyst and limits its industrial application.Herein,a lattice Cl^(-)functioned NiFe-LDH electrode(E-NF-LDHCl or E-NF-LDHSW)is firstly constructed by a minute-level electrochemistry assisted chlorine corrosion strategy,which presents enhanced oxygen evolution reaction(OER)performance and excellent anti-Cl^(-)corrosion behavior for seawater splitting.The optimized E-NF-LDHCl and E-NF-LDHSW deliver low OER overpotential of 355 and 384 mV to reach 1 A cm^(-2)current density in the 1 mol L^(-1)KOH and 1 mol L^(-1)KOH seawater,respectively,as well as excellent stability of E-NF-LDHCl is maintained at 1 A cm-2 for 400 h in the 1 mol L^(-1)KOH and 1 mol L^(-1)KOH+0.5 mol L^(-1)NaCl.MD(molecular dynamics)simulation and DFT(density functional theory)calculation confirmed that strong common-ion repulsion effect in IHP region repels free Cl^(-),forming high spin polarization centers and more single electrons to enhance the intrinsic activity of OER.展开更多
Development of highly active electrocatalysts for oxygen evolution reaction(OER)is one of the critical issues for water splitting,and most reported catalysts operate at overpotentials above 190 mV.Here we present a mu...Development of highly active electrocatalysts for oxygen evolution reaction(OER)is one of the critical issues for water splitting,and most reported catalysts operate at overpotentials above 190 mV.Here we present a multiphase nickel iron sulfide(MPS)hybrid electrode with a hierarchical structure of iron doped NiS and Ni3S2,possessing a benchmark OER activity in alkaline media with a potential as low as 1.33 V(vs.reversible hydrogen electrode)to drive an OER current density of 10 mA cm^-2.The Fe doped NiS,combined with highly conductive disulfide phase on porous Ni foam,is believed to be responsible for the ultrahigh activity.Furthermore,density functional theory simulation reveals that partially oxidized sulfur sites in Fe doped NiS could dramatically lower the energy barrier for the rate-determining elementary reaction,thus contributing to the active oxygen evolution.展开更多
The catalytic/electrocatalytic performance of platinum(Pt)nanostructures highly relates to their morphology.Herein,we propose a facile self-template pyrolysis strategy at high temperature to synthesize one-dimensional...The catalytic/electrocatalytic performance of platinum(Pt)nanostructures highly relates to their morphology.Herein,we propose a facile self-template pyrolysis strategy at high temperature to synthesize one-dimensionally holey Pt nanotubes(Pt-hNTs)using Pt^(Ⅱ)-dimethylglyoxime complex(Pt^(Ⅱ)-DMG)nanorods as the reaction precursor.The coordination capability of DMG results in the generation of Pt^(Ⅱ)-DMG nanorods,whereas the reducibility of DMG at high temperature leads to the reduction of Pt^(Ⅱ)species in Pt^(Ⅱ)-DMG nanorods.During the reaction process,the inside-out Ostwald ripening phenomenon leads to the hollow morphology of Pt-hNTs.Benefiting from the physical characteristics of hollow and holey structure,Pt-hNTs with clean surface show superior electroactivity and durability for catalyzing ethanol electrooxidation as well as hydrogen evolution reaction in alkaline media.Under optimized experimental conditions,the constructed symmetric Pt-hNTs||Pt-hNTs ethanol electrolyzer only requires an electrolysis voltage of 0.40 V to achieve the electrochemical hydrogen production,demonstrating a highly energy saving strategy relative to traditional water electrolysis.展开更多
The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the ...The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the electronic properties of LaCoO_(3) by fine-tuning its crystal facet and atomic doping.LaCoO_(3) samples with oriented(110)(LCO(110))and(111)(LCO(111))facets were motivated by a capping agent(Sr^(2+)).Compared with the LCO(111)plane,the LCO(110)and Sr-doped LCO(111)(LSCO(111))planes possessed higher O 2p positions,stronger Co 3d-O 2p covalencies,and higher Co spin states by inducing CoO_(6) distortion,thus leading to superior oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)performances.Specifically,the overpotentials at 10 mA cm^(−2) were 299,322,and 289 mV for LCO(110),LCO(111),and LSCO(111),respectively.In addition,the(110)crystal facet and Sr substitution bestowed enhanced stability on LaCoO_(3) due to the strengthened Co-O bonding.The present work enlightens new avenues of regulating electronic properties by crystal facet engineering and atom doping and provides a valuable reference for the electron structure-electrocatalytic activity connection for OER and HER.展开更多
A low-cost,highly efficient and strong durable bifunctional electrocatalyst is crucial for electrochemical overall water splitting.In this paper,a self-templated strategy combined with in-situ phosphorization is appli...A low-cost,highly efficient and strong durable bifunctional electrocatalyst is crucial for electrochemical overall water splitting.In this paper,a self-templated strategy combined with in-situ phosphorization is applied to construct hollow structured bimetallic cobalt-nickel phosphide(CoNiP_(x))nanocages.Owing to their unique hollow structure and bimetallic synergistic effects,the as-synthesized CoNiP_(x)hollow nanocages exhibit a high electrocatalytic activity and stability towards hydrogen evolution reaction in all-pH electrolyte and a remarkable electrochemical performance for oxygen evolution reaction in 1.0 mol L^(-1)KOH.Meanwhile,with the bifunctional electrocatalyst in both anode and cathode for overall water splitting,a low voltage of 1.61 V and superior stability are achieved at a current density of 20 mA cm^(-2).展开更多
文摘Water splitting powered by clean electricity is a sustainable and promising approach to produce green hydrogen.Currently,noble metal(e.g.Iridium,Ruthenium,Platinum)-based catalysts are most widely used for water splitting electrolysis.However,noble metal-based catalysts often suffer from multiple disadvantages,including high cost,low selectivity and poor durability.The emergence of metal-organic framework nanosheets(MOFNSs)attracts significant attention due to their unique advantages.Here,a concise,yet comprehensive and critical,review of recent advances in the field of MOFNSs is provided.This review explains the fundamental oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)catalytic mechanisms as well as key characterization techniques for the structure-activity relationship study are discussed.Moreover,it discusses efficient design strategies and the brief research advances of MOFNSs in HER,OER,and bifunctional electrocatalysis,along with some challenges and opportunities.
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.
文摘The large‐scale application of proton exchange membrane water electrolysis technology requires the development of high‐performance oxygen evolution electrocatalysts with as little iridium(Ir)as possible.Ir‐based double perovskite oxides(A_(2)B’IrO_(6);A=alkaline,alkaline‐earth,or rare‐earth elements;B’=transition metal or rare‐earth elements)represent a class of oxides with great potential to replace the commercial catalyst IrO_(2).However,the structural evolution of Ir‐based double perovskite oxides in electrolytes is incompletely understood,and foundational knowledge of the design principle of the“ideal”material is lacking.In this work,we report the unexpected phenomenon of instant Ir leaching from Ir‐based double perovskite oxides in acid under non‐catalytic conditions and discuss the implications of this phenomenon for mechanism investigation and material identification.Some well‐known Ir‐based double perovskite oxides,such as Ba_(2)PrIrO_(6) and Sr_(2)YIrO_(6),undergo instantaneous Ir leaching when they come into contact with acidic electrolytes.The Ir‐leaching process is found to be non‐persistent and non‐thermodynamically determined,and its extent is correlated with the leaching of other B’‐site elements in the perovskite oxides.Based on this observation,we revisit the Ir dissolution‐precipitation process for surface IrO_(x) formation during the perovskite‐electrolyzed oxygen evolution reaction,emphasizing the non‐negligible role of Ir species owing to acid corrosion in the electrolyte.Finally,we modify a screening protocol for low‐Ir oxygen evolution electrocatalysts and propose an instant acid corrosion test as an indispensable process to evaluate the structural stability of potential 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 Chemical,Biological,Environmental,and Transport Systems(CBET)program of US National Science Foundation(CBET-1438440)~~
文摘An efficient and economical oxygen evolution reaction(OER)catalyst is critical to the widespread application of solar energy to fuel conversion.Among many potential OER catalysts,the metal oxyhydroxides,especially FeOOH,show promising OER reactivity.In the present work,we performed a DFT+U study of the OER mechanism on theγ‐FeOOH(010)surface.In particular,we established the chemical potential of the OH?and hole pair and included the OH?anion in the reaction pathway,accounting to the alkaline conditions of anodic OER process.We then analyzed the OER pathways on the surface with OH‐,O‐and Fe‐terminations.On the surface with OH‐and O‐terminations,the O2molecule could form from either OH reacting with the surface oxygen species(-OH*and-O*)or the combination of two surface oxygen species.On the Fe‐terminated surface,O2can only form by adsorbing OH on the Fe sites first.The potential‐limiting step of the oxygen evolution with different surface terminations was determined by following the free‐energy change of the elementary steps along each pathway.Our results show that oxygen formation requires recreating the surface Fe sites,and consequently,the condition that favors the partially exposed Fe sites will promote oxygen formation.
文摘Efficient and stable bifunctional electrocatalysts for water splitting is essential for producing hydrogen and alleviating huge energy consumption.Meanwhile,charge transfer engineering is an efficient approach to modulate the localized electronic properties of catalysts and tune the electrocatalytic performance.Herein,we tactfully fabricate PtFeNi alloys/NiFe layered double hydroxides(LDHs)heterostructure by an easily electrochemical way with a small amount of Pt.The experimental and theoretical results unravel that the charge transfer on the alloy clusters modulated by the defective substrates(NiFe LDHs),which synergistically optimizes the adsorption energy of the reaction intermediates.The electrocatalyst exhibits an ultra‐low overpotential of 81 and 243 mV at the current density of 100 mA cm^(–2) for hydrogen evolution and oxygen evolution,respectively.Furthermore,the overall water splitting indicates that PtFeNi alloys/NiFe LDHs presents an ultra‐low overpotential of 265 and 406 mV to reach the current density of 10 and 300 mA cm^(–2),respectively.It proves that the PtFeNi alloys/NiFe LDHs catalyst is an excellent dual‐function electrocatalyst for water splitting and promising for industrialization.This work provides a new electrochemical approach to construct the alloy heterostructure.The prepared heterostructures act as an ideal platform to investigate the charge re‐distribution behavior and to improve the electrocatalytic activity.
文摘Catalytic water splitting potentially reduce the consumption of fossil fuels and has received intense research attention.Synergy effects in multi‐element transition metal‐based water splitting catalysts have evoked special interests.Studies on catalysts in interfacial structures are especially meaningful due to their pertinence in applications.In this study,we report the synergy effects in promoting catalytic power in the ternary transition metal Zn,Co,Ni alloy nanoparticles that embeds in the carbonized Ppy/CNT multilayered matrix.By comparison with a series of binary or single metal counterparts,the mechanism under the synergy effects are elucidated.Experimental and DFT calculation results indicate that the ternary transition metal catalysts in the N‐doped carbon matrix present special electronic structure,which benefits the reversible transition‐state adsorption in HER and OER and render the catalysts high conductivity in room temperature.We expect our findings inspire further development of efficient transition metal HER and OER catalysts.
文摘As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this issue.Herein,we successfully fabricated a three-dimensional iron-dysprosium oxide co-regulated in-situ formed MOF-Ni arrays on carbon cloth(FeDy@MOF-Ni/CC)through a facile two-step hydrothermal method.Electrochemical studies demonstrate that the designed FeDy@MOF-Ni/CC catalyst requires an overpotential of only 251 mV to reach 10 mA cm-2 with a small Tafel slope of 52.1 mV dec-1.Additionally,the stability declined by only 5.5%after 80 h of continuous testing in 1.0 M KOH.Furthermore,a cell voltage of only 1.57 V in the overall water splitting system is sufficient to achieve 10 mA cm-2;this value is far better than that of most previously reported catalysts.The excellent catalytic performance originates from the unique 3D rhombus-like structure,as well as coupling synergies of Fe-Dy-Ni species.The combination of lanthanide and transition metal species in the synthesis strategy may open entirely new possibilities with promising potential in the design of highly active OER electrocatalysts.
文摘Although the intermittent energy-driven direct seawater splitting technology provides an unparalleled approach to achieving sustainable development,the severe corrosion via aggressive Cl^(-)severely affects the stability and efficiency of the anode catalyst and limits its industrial application.Herein,a lattice Cl^(-)functioned NiFe-LDH electrode(E-NF-LDHCl or E-NF-LDHSW)is firstly constructed by a minute-level electrochemistry assisted chlorine corrosion strategy,which presents enhanced oxygen evolution reaction(OER)performance and excellent anti-Cl^(-)corrosion behavior for seawater splitting.The optimized E-NF-LDHCl and E-NF-LDHSW deliver low OER overpotential of 355 and 384 mV to reach 1 A cm^(-2)current density in the 1 mol L^(-1)KOH and 1 mol L^(-1)KOH seawater,respectively,as well as excellent stability of E-NF-LDHCl is maintained at 1 A cm-2 for 400 h in the 1 mol L^(-1)KOH and 1 mol L^(-1)KOH+0.5 mol L^(-1)NaCl.MD(molecular dynamics)simulation and DFT(density functional theory)calculation confirmed that strong common-ion repulsion effect in IHP region repels free Cl^(-),forming high spin polarization centers and more single electrons to enhance the intrinsic activity of OER.
基金supported by the National Natural Science Foundation of Chinathe National Key Research and Development Project (2018YFB1502401)+4 种基金the Royal Society and Newton Fund through Newton Advanced Fellowship award (NAF\R1\191294)the Program for Changjiang Scholars and Innovative Research Team in the Universitythe Fundamental Research Funds for the Central Universitiesthe Longterm Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of Chinathe financial support from China Scholarships Council (CSC)
文摘Development of highly active electrocatalysts for oxygen evolution reaction(OER)is one of the critical issues for water splitting,and most reported catalysts operate at overpotentials above 190 mV.Here we present a multiphase nickel iron sulfide(MPS)hybrid electrode with a hierarchical structure of iron doped NiS and Ni3S2,possessing a benchmark OER activity in alkaline media with a potential as low as 1.33 V(vs.reversible hydrogen electrode)to drive an OER current density of 10 mA cm^-2.The Fe doped NiS,combined with highly conductive disulfide phase on porous Ni foam,is believed to be responsible for the ultrahigh activity.Furthermore,density functional theory simulation reveals that partially oxidized sulfur sites in Fe doped NiS could dramatically lower the energy barrier for the rate-determining elementary reaction,thus contributing to the active oxygen evolution.
基金supported by the Natural Science Foundation of Hainan Province(2019RC007)Key Research and Development Project of Hainan Province(ZDYF2020037)+5 种基金the National Natural Science Foundation of China(21875133 and 51873100)Natural Science Foundation of Shaanxi Province(2020JZ-23)Fundamental Research Funds for the Central Universities(GK202101005,GK201901002,2019TS007,2021CBLZ004,and 2020CSLZ012)the Innovation Team Project for Graduate Students at Shaanxi Normal University(TD2020048Y)Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials at Guangxi University(2021GXYSOF02)the 111 Project(B14041)。
文摘The catalytic/electrocatalytic performance of platinum(Pt)nanostructures highly relates to their morphology.Herein,we propose a facile self-template pyrolysis strategy at high temperature to synthesize one-dimensionally holey Pt nanotubes(Pt-hNTs)using Pt^(Ⅱ)-dimethylglyoxime complex(Pt^(Ⅱ)-DMG)nanorods as the reaction precursor.The coordination capability of DMG results in the generation of Pt^(Ⅱ)-DMG nanorods,whereas the reducibility of DMG at high temperature leads to the reduction of Pt^(Ⅱ)species in Pt^(Ⅱ)-DMG nanorods.During the reaction process,the inside-out Ostwald ripening phenomenon leads to the hollow morphology of Pt-hNTs.Benefiting from the physical characteristics of hollow and holey structure,Pt-hNTs with clean surface show superior electroactivity and durability for catalyzing ethanol electrooxidation as well as hydrogen evolution reaction in alkaline media.Under optimized experimental conditions,the constructed symmetric Pt-hNTs||Pt-hNTs ethanol electrolyzer only requires an electrolysis voltage of 0.40 V to achieve the electrochemical hydrogen production,demonstrating a highly energy saving strategy relative to traditional water electrolysis.
基金supported by the National Natural Science Foundation of China(52174283)。
文摘The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the electronic properties of LaCoO_(3) by fine-tuning its crystal facet and atomic doping.LaCoO_(3) samples with oriented(110)(LCO(110))and(111)(LCO(111))facets were motivated by a capping agent(Sr^(2+)).Compared with the LCO(111)plane,the LCO(110)and Sr-doped LCO(111)(LSCO(111))planes possessed higher O 2p positions,stronger Co 3d-O 2p covalencies,and higher Co spin states by inducing CoO_(6) distortion,thus leading to superior oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)performances.Specifically,the overpotentials at 10 mA cm^(−2) were 299,322,and 289 mV for LCO(110),LCO(111),and LSCO(111),respectively.In addition,the(110)crystal facet and Sr substitution bestowed enhanced stability on LaCoO_(3) due to the strengthened Co-O bonding.The present work enlightens new avenues of regulating electronic properties by crystal facet engineering and atom doping and provides a valuable reference for the electron structure-electrocatalytic activity connection for OER and HER.
基金the National Key R&D Program of China(2017YFA 0208300 and 0700104)the National Natural Science Foundation of China(21671180)the State Key Laboratory of Organic Inorganic Composites(oic-201801007)。
文摘A low-cost,highly efficient and strong durable bifunctional electrocatalyst is crucial for electrochemical overall water splitting.In this paper,a self-templated strategy combined with in-situ phosphorization is applied to construct hollow structured bimetallic cobalt-nickel phosphide(CoNiP_(x))nanocages.Owing to their unique hollow structure and bimetallic synergistic effects,the as-synthesized CoNiP_(x)hollow nanocages exhibit a high electrocatalytic activity and stability towards hydrogen evolution reaction in all-pH electrolyte and a remarkable electrochemical performance for oxygen evolution reaction in 1.0 mol L^(-1)KOH.Meanwhile,with the bifunctional electrocatalyst in both anode and cathode for overall water splitting,a low voltage of 1.61 V and superior stability are achieved at a current density of 20 mA cm^(-2).
