Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catal...Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.展开更多
Layered sodium cobaltate(Na_(x)CoO_(2)),characterized by CoO_(2) slabs and intralayer edge-shared CoO_6 octahedra,holds promising potential as an electrocatalyst for chlorine evolution reaction(CER).However,the subopt...Layered sodium cobaltate(Na_(x)CoO_(2)),characterized by CoO_(2) slabs and intralayer edge-shared CoO_6 octahedra,holds promising potential as an electrocatalyst for chlorine evolution reaction(CER).However,the suboptimal adsorption of the intermediate on Na_(x)CoO_(2) resulted in unsatisfactory activity.Herein,Na_(x)CoO_(2) flakes with varying sodium densities(x=0.6,0.7,0.9)were engineered for efficient CER.Excitingly,the optimal Na_(0.7)CoO_(2) achieves an ultralow overpotential(55.47 mV)outperforming commercial RuO_(2) at 10 mA/cm^(2),while remaining inactive toward the competing OER.Experimental and theoretical calculations demonstrate that appropriate interlayer sodium density has optimized the d-band center level of Co atoms in Na_(x)CoO_(2),thereby weakening the strength of Co-Cl bonds.This modulation facilitates the adsorption-desorption equilibrium of Cl species(ΔG_(Cl^(*))=-0.109 eV)on the surface and kinetically accelerating Cl_2 release.This work is anticipated to elucidate the mechanism by which interlayer sodium density modifies the catalytic performance of Na_(x)CoO_(2),and present new insights for the rational design of advanced CER electrocatalysts.展开更多
The chlor-alkali industry faces high energy consumption,competition between the chlorine evolution reaction(CER)and oxygen evolution reaction(OER),and challenges,such as high costs and poor stability of precious metal...The chlor-alkali industry faces high energy consumption,competition between the chlorine evolution reaction(CER)and oxygen evolution reaction(OER),and challenges,such as high costs and poor stability of precious metal catalysts in chlorine production.At the same time,the treatment of antibiotic pollution urgently requires efficient degradation technologies.In this study,a non-precious metal anode of CuCo_(2)S_(4)/Ti(CCS/Ti)with a nanosheet structure was constructed on a foam titanium substrate using a hydrothermal method,achieving dual-functional applications for efficient chlorine evolution and the degradation of ofloxacin(OFX).The electrode exhibits an overpotential of 1.23 V(vs.Ag/AgCl)at a current density of 100 mA·cm^(−2),with a Faradaic efficiency of 95.66%,and remains stable for 180 h.Density functional theory(DFT)calculations indicate that the chlorine evolution mechanism on the CCS/Ti electrode primarily follows the Volmer-Heyrovsky pathway.Furthermore,the CCS/Ti electrode achieves a degradation efficiency of 91.34%for OFX within 5 min and demonstrates broad-spectrum degradation capabilities for various fluoroquinolone antibiotics(>83.05%).This study provides an efficient and cost-effective new approach for catalyst material design,contributing to the greening of the chlor-alkali industry and the treatment of refractory pollutants.展开更多
Chlorine(Cl2)is one of the most important chemicals produced by the electrolysis of brine solutions and is a key raw material for many areas of industrial chemistry.For nearly half a century,dimensionally stable anode...Chlorine(Cl2)is one of the most important chemicals produced by the electrolysis of brine solutions and is a key raw material for many areas of industrial chemistry.For nearly half a century,dimensionally stable anode(DSA)made from a mixture of RuO_(2) and TiO_(2) solid oxides coated on Ti substrate has been the most widely used electrode for chlorine evolution reaction(CER).In harsh operating environments,the stability of DSAs remains a major challenge greatly affecting their lifetime.The deactivation of DSAs significantly increases the cost of the chlor-alkali industry due to the corrosion of Ru and the formation of the passivation layer TiO_(2).Therefore,it is urgent to develop catalysts with higher activity and stability,which requires a thorough understanding of the deactivation mechanism of DSA catalysts.This paper reviews existing references on the deactivation mechanisms of DSA catalysts,including both experimental and theoretical studies.Studies on how CER selectivity affects electrode stability are also discussed.Furthermore,studies on the effects of the preparation process,elemental composition,and surface/interface structures on the DSA stability and corresponding improvement strategies are summarized.The development of other non-DSA-type catalysts with comparable stability is also reviewed,and future opportunities in this exciting field are also outlined.展开更多
The chlorine evolution reaction(CER)is a crucial step in the production of chlorine gas and active chlorine by chlor-alkali electrolysis.Currently,the endeavor to fabricate electrodes capable of yielding high current ...The chlorine evolution reaction(CER)is a crucial step in the production of chlorine gas and active chlorine by chlor-alkali electrolysis.Currently,the endeavor to fabricate electrodes capable of yielding high current density at minimal overpotential remains a central challenge in advancing the realm of chlorine evolution reactions.Here,we grow TiO_(2)and RuO_(2)on MXene@carbon cloth(CC)through the favorable affinity and induced deposition effect between the surface functional groups of MXene and the metal.A self-supported electrode(RuTiO_(2)/MXene@CC)with strong binding at the electrocatalyst-support interface and weak adhesion at electrocatalyst-bubble interface is constructed.The RuTiO_(2)/MXene@CC can reduce the electron density of RuO_(2)by regulating the electron redistribution at the heterogeneous interface,thus enhancing the adsorption of Cl−.RuTiO_(2)/MXene@CC could achieve a high current density of 1000 mA·cm^(−2)at a small overpotential of 220 mV,superior to commercial dimensionally stable anodes(DSA).This study provides a new strategy for constructing efficient CER catalysts at high current density.展开更多
Direct electrolysis of seawater to produce green hydrogen is a more environmentally friendly process than freshwater electrolysis.The renewable energy sector exhibits tremendous interest in practical seawater electrol...Direct electrolysis of seawater to produce green hydrogen is a more environmentally friendly process than freshwater electrolysis.The renewable energy sector exhibits tremendous interest in practical seawater electrolysis techniques due to its substantial capacity to mitigate the need for freshwater consumption.With the low catalytic efficiency of the current seawater splitting process and the poor reliability of its operation,the process suffers from severe corrosion caused by chloride ions,as well as anodic competition between oxygen evolution and chlorine oxidation reactions.This review provides an overview of the latest electrocatalyst developments for promoting selectivity and stability in seawater electrolysis.Using the characterization and simulation results,as well as active machine learning,advanced electrocatalytic materials can be designed and developed,a research direction that will become increasingly important in the future.A variety of strategies are discussed in detail for designing advanced electrocatalysts in seawater electrolysis,including the surface protective layer,structural regulation by heteroatom doping and vacancies,porous structure,core-shell construction,and 3D hetero-structure construction to hinder chlorine evolution reactions.Finally,future perspectives and challenges for green hydrogen production from seawater electrolysis are also described.展开更多
Earth-abundant seawater resource has become an attractive candidate to produce hydrogen from electrolysis,which is of great significance to realize hydrogen economy and carbon neutrality.Nonetheless,developing highly ...Earth-abundant seawater resource has become an attractive candidate to produce hydrogen from electrolysis,which is of great significance to realize hydrogen economy and carbon neutrality.Nonetheless,developing highly active and stable electrocatalysts to meet the needs of highly effective seawater splitting is still challenging for the sluggish oxygen evolution dynamics and the existed competitive reaction of chlorine evolution reaction(CER).To this end,some newly-developed electrocatalysts with superior performance,such as noble metals,alloy,transition metals,oxides,carbides,nitrides,phosphides,and so on,have been synthesized for the seawater splitting in recent years.This review starts from the historical background and fundamental mechanisms,and summarizes the most recent progress in the development of seawater electrolysis technologies.Some existing issues in the process of seawater electrolysis are enumerated and the corresponded solutions are presented.The future of hydrogen production from seawater electrolysis,especially the design and synthesis of novel catalysts for seawater electrolysis,is prospected.展开更多
As an energy-intensive industry,the chlor-alkali process has caused numerous environmental issues due to heavy electricity consumption and pollution.Chlor-alkali industry has been upgraded from mercury,diaphragm elect...As an energy-intensive industry,the chlor-alkali process has caused numerous environmental issues due to heavy electricity consumption and pollution.Chlor-alkali industry has been upgraded from mercury,diaphragm electrolytic cell,to ion exchange membrane(IEM)electrolytic cells.However,several challenges,such as the selectivity of the anodic reaction,sluggish kinetics of alkaline hydrogen evolution,degradation of membranes,the reasonable design of electrolytic cell structure,remain to be addressed.For these reasons,this paper mainly reviews the research progress of the chlor-alkali industry from materials to devices,including hydrogen evolution anode,chlorine evolution cathode,IEM,and electrolytic cell system.Finally,the research directions and prospects in the chlor-alkali industry are proposed for its further improvement.展开更多
Scaled-up industrial water electrolysis equipment that can be used with abundant seawater is key for affordable hydrogen production.The search for highly stable,dynamic,and economical electrocatalysts could have a sig...Scaled-up industrial water electrolysis equipment that can be used with abundant seawater is key for affordable hydrogen production.The search for highly stable,dynamic,and economical electrocatalysts could have a significant impact on hydrogen commercialization.Herein,we prepared energy-efficient,scalable,and engineering electronic structure modulated Mn-Ni bimetal oxides(Mn_(0.25)Ni_(0.75)O)through simple hydrothermal followed by calcination method.As-optimized Mn_(0.25)Ni_(0.75)O displayed enhanced oxygen and hydrogen evolution reaction(OER and HER)performance with overpotentials of 266 and115 mV at current densities of 10 mA cm^(-2)in alkaline KOH added seawater electrolyte solution.Additionally,Mn-Ni oxide catalytic benefits were attributed to the calculated electronic configurations and Gibbs free energy for OER,and HER values were estimated using first principles calculations.In real-time practical application,we mimicked industrial operating conditions with modified seawater electrolysis using Mn_(0.25)Ni_(0.75)O‖Mn_(0.25)Ni_(0.75)O under various temperature conditions,which performs superior to the commercial IrO_(2)‖Pt-C couple.These findings demonstrate an inexpensive and facile technique for feasible large-scale hydrogen production.展开更多
To improve the durability as well as to reduce the cost of anodes, the IrO2＋MnO2 composite coating anodes for NaCIO production were prepared by thermal decomposition. Scanning electron microscopy （SEM）, energy disp...To improve the durability as well as to reduce the cost of anodes, the IrO2＋MnO2 composite coating anodes for NaCIO production were prepared by thermal decomposition. Scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDX）, and X-ray diffraction analysis （XRD） were carried out to investigate the morphologies, element distribution, and microstructure. The anodic polarization curves were employed to study the effect of sintering temperature on the Cl2 evolution reaction （CER） of the electrodes. The accelerated life tests （ALT） and electrochemical impedance spectroscopy measurement （EIS） were utilized to investigate the stability. The rules of NaCIO production were also studied by the static electrolysis experiment. The results indicate that sintering temperature has a significant influence on the CER properties as well as the ALT values of the electrodes. The electrode prepared at 400℃ has the best CER properties and the longest ALT value.展开更多
Transition metal based bimetallic oxides are good candidates for electrocatalytic oxygen evolution owing to their variable oxidation states,synergistic effects,good conductivity,convincing electrochemical stability,an...Transition metal based bimetallic oxides are good candidates for electrocatalytic oxygen evolution owing to their variable oxidation states,synergistic effects,good conductivity,convincing electrochemical stability,and low cost.However,these materials are highly susceptible to corrosion during saline seawater electrolysis.This work,for the first time,highlights the role of cerium(Ce)doping in bimetallic strontium cobalt oxide(SrCoO_(x))electrocatalyst for electrochemically stable and corrosion-resistant oxygen evolution reaction(OER)in simulated saline water.The experimental results reveal that 0.5%Ce-doped 5%SrCoO_(x) has the best corrosion resistant ability with respect to the undoped SrCoO_(x) and various other Cedoped samples.The growth of CeO_(2) nanoparticles and the generation of CeO_(x) passivation layer through Ce doping were supposed to block the corrosive ions on the surface,thereby hindering chlorine evolution reaction(CER).The Ce^(3+)ions doped inside the SrCoO_(x) lattice created multiple defects and vacancies which sacrificially facilitate the OER while mitigating the CER.The suppression of corrosive reactions was indicated through low corrosion current(−1.10μA·cm^(−2))and high corrosion potential(0.90 V vs.RHE)values suggesting slowest corrosion rate and least tendency towards CER in 0.5%Ce-doped 5%SrCoO_(x).Consequently,it demonstrated the least Tafel slope of 81.7 mV·dec^(−1) in saline OER electrolysis with respect to the 121.0 mV·dec^(−1) was obtained for undoped 5%SrCoO_(x).Moreover,the electrochemical stability demonstrated in chronoamperometric OER for 45 h and the cyclic voltammetry(500 cycles)confirmed that 0.5%Ce-doped SrCoO_(x) electrocatalyst possesses enhanced anticorrosive properties,which was further supported by post-use linear sweep voltammetry,cyclic voltammetry,and X-ray diffraction analyses.Linear polarization resistance study was also employed on the seawater sample,collected locally,to assess the validity of the present work in real marine systems.In view of the observed results,this work can open an alternate pathway to investigate various transition metal oxide systems as potential corrosion resistant electrocatalysts for seawater.展开更多
The chlorine evolution reaction(CER)serves as the cornerstone and crucial step in the conversion of chloride ions to chlorine gas,while accompanied by the occurrence of the oxygen evolution reaction(OER)in practical p...The chlorine evolution reaction(CER)serves as the cornerstone and crucial step in the conversion of chloride ions to chlorine gas,while accompanied by the occurrence of the oxygen evolution reaction(OER)in practical processes that lead to difficulty in achieving the purity requirements of the product Cl_(2)for industrial applications.Pd-doped Co_(3)O_(4) nanoneedles(Pd-Co_(3)O_(4)NNs)were synthesized via hydrothermal-calcination methods.Pd sites induce electron delocalization,creating asymmetric active Co sites in Co_(3)O_(4),enhancing CER performance.The unique nanoneedle arrays of the designed catalysts increase the number of exposed active sites,facilitating electron transfer and endowing the Pd-Co_(3)O_(4)NNs with a tip catalytic effect,further optimizing the catalytic reaction kinetics of CER with an overpotential of 118 mV at 100 mA cm^(-2)and a Tafel slope of 53.93 mV dec^(-1).The density functional theory(DFT)calculations reveal that Pd incorporation at octahedral sites triggers charge redistribution and d-band center downshift,weakening intermediate adsorption and sustaining catalytic activity.This work offers new insights into noble-metal-doped spinel oxides,highlighting their potential for industrial applications.展开更多
Direct electrolytic splitting of seawater for the production of H2 using ocean energy is a promising technology that can help achieve carbon neutrality.However,owing to the high concentrations of chlorine ions in seaw...Direct electrolytic splitting of seawater for the production of H2 using ocean energy is a promising technology that can help achieve carbon neutrality.However,owing to the high concentrations of chlorine ions in seawater,the chlorine evolution reaction always competes with the oxygen evolution reaction(OER)at the anode,and chloride corrosion occurs on both the anode and cathode.Thus,effective electrocatalysts with high selectivity toward the OER and excellent resistance to chloride corrosion should be developed.In this critical review,we focus on the prospects of state-of-the-art metal-oxide electrocatalysts,including noble metal oxides,non-noble metal oxides and their compounds,and spinel-and perovskite-type oxides,for seawater splitting.We elucidate their chemical properties,excellent OER selectivity,outstanding anti-chlorine-corrosion performance,and reaction mechanisms.In particular,we review metal oxides that operate at high current densities,near industrial application levels,based on special catalyst design strategies.展开更多
The direct electrolytic splitting of abundant seawater instead of scarce freshwater is an ideal strategy for producing clean and renewable hydrogen(H 2)fuels.The oxygen evolution reaction(OER)is a vital half-reaction ...The direct electrolytic splitting of abundant seawater instead of scarce freshwater is an ideal strategy for producing clean and renewable hydrogen(H 2)fuels.The oxygen evolution reaction(OER)is a vital half-reaction that occurs during electrochemical seawater splitting.However,OER suffers from sluggish four-electron transfer kinetics and competitive chlorine evolution reactions in seawater.Noble metal-based catalysts such as IrO_(2) and RuO_(2) are considered to have state-of-the-art OER electrocatalytic activity,but the low reserves and high prices of these noble metals significantly limit their large-scale application.Recently,efforts have been made to explore efficient,robust,and anti-chlorine-corrosion non-noble-metal OER electrocatalysts for seawater splitting such as oxides,hydroxides,phosphides,nitrides,chalcogenides,alloys,and composites.An in-depth understanding of the fundamentals of seawater electrolysis and the design principle of electrode materials is important for promoting seawater-splitting technology.In this review,we first introduce fundamental reactions in seawater electrolytes.Subsequently,construction strategies for OER electrocatalysts for seawater splitting are introduced.Finally,present challenges and perspectives regarding non-noble-metal OER electrocatalysts for commercial H 2 production by seawater splitting are discussed.展开更多
基金the National Natural Science Foundation of China(U21A20286,22206054 and 21805069)Natural Science Foundation of Hubei(2021CFB094)the Fundamental Research Funds for the Central China Normal University(CCNU)for financial support。
文摘Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.
基金jointly supported by the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.24JR031)the Research Fund of Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials(No.SKL001)+1 种基金the National Natural Science Foundation of China(No.52372288)the Natural Science Basic Research Program of Shaanxi(No.2022JQ-373)。
文摘Layered sodium cobaltate(Na_(x)CoO_(2)),characterized by CoO_(2) slabs and intralayer edge-shared CoO_6 octahedra,holds promising potential as an electrocatalyst for chlorine evolution reaction(CER).However,the suboptimal adsorption of the intermediate on Na_(x)CoO_(2) resulted in unsatisfactory activity.Herein,Na_(x)CoO_(2) flakes with varying sodium densities(x=0.6,0.7,0.9)were engineered for efficient CER.Excitingly,the optimal Na_(0.7)CoO_(2) achieves an ultralow overpotential(55.47 mV)outperforming commercial RuO_(2) at 10 mA/cm^(2),while remaining inactive toward the competing OER.Experimental and theoretical calculations demonstrate that appropriate interlayer sodium density has optimized the d-band center level of Co atoms in Na_(x)CoO_(2),thereby weakening the strength of Co-Cl bonds.This modulation facilitates the adsorption-desorption equilibrium of Cl species(ΔG_(Cl^(*))=-0.109 eV)on the surface and kinetically accelerating Cl_2 release.This work is anticipated to elucidate the mechanism by which interlayer sodium density modifies the catalytic performance of Na_(x)CoO_(2),and present new insights for the rational design of advanced CER electrocatalysts.
基金supported by the Major Science and Technology Projects in Yunnan Province(China)(No.202302AE090014)the National Natural Science Foundation of China(No.5196080497).
文摘The chlor-alkali industry faces high energy consumption,competition between the chlorine evolution reaction(CER)and oxygen evolution reaction(OER),and challenges,such as high costs and poor stability of precious metal catalysts in chlorine production.At the same time,the treatment of antibiotic pollution urgently requires efficient degradation technologies.In this study,a non-precious metal anode of CuCo_(2)S_(4)/Ti(CCS/Ti)with a nanosheet structure was constructed on a foam titanium substrate using a hydrothermal method,achieving dual-functional applications for efficient chlorine evolution and the degradation of ofloxacin(OFX).The electrode exhibits an overpotential of 1.23 V(vs.Ag/AgCl)at a current density of 100 mA·cm^(−2),with a Faradaic efficiency of 95.66%,and remains stable for 180 h.Density functional theory(DFT)calculations indicate that the chlorine evolution mechanism on the CCS/Ti electrode primarily follows the Volmer-Heyrovsky pathway.Furthermore,the CCS/Ti electrode achieves a degradation efficiency of 91.34%for OFX within 5 min and demonstrates broad-spectrum degradation capabilities for various fluoroquinolone antibiotics(>83.05%).This study provides an efficient and cost-effective new approach for catalyst material design,contributing to the greening of the chlor-alkali industry and the treatment of refractory pollutants.
文摘Chlorine(Cl2)is one of the most important chemicals produced by the electrolysis of brine solutions and is a key raw material for many areas of industrial chemistry.For nearly half a century,dimensionally stable anode(DSA)made from a mixture of RuO_(2) and TiO_(2) solid oxides coated on Ti substrate has been the most widely used electrode for chlorine evolution reaction(CER).In harsh operating environments,the stability of DSAs remains a major challenge greatly affecting their lifetime.The deactivation of DSAs significantly increases the cost of the chlor-alkali industry due to the corrosion of Ru and the formation of the passivation layer TiO_(2).Therefore,it is urgent to develop catalysts with higher activity and stability,which requires a thorough understanding of the deactivation mechanism of DSA catalysts.This paper reviews existing references on the deactivation mechanisms of DSA catalysts,including both experimental and theoretical studies.Studies on how CER selectivity affects electrode stability are also discussed.Furthermore,studies on the effects of the preparation process,elemental composition,and surface/interface structures on the DSA stability and corresponding improvement strategies are summarized.The development of other non-DSA-type catalysts with comparable stability is also reviewed,and future opportunities in this exciting field are also outlined.
基金the National Natural Science Foundation of China(Nos.21971132,52072197,and 52272222)Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(No.2019KJC004)+5 种基金Major Scientific and Technological Innovation Project(No.2019JZZY020405)Major Basic Research Program of Natural Science Foundation of Shandong Province(No.ZR2020ZD09)Taishan Scholar Young Talent Program(No.tsqn201909114)the 111 Project of China(No.D20017)Shandong Province Double-Hundred Talent Plan(No.WST2020003)State Key Laboratory of Heavy Oil Processing(No.SKLHOP202202006).
文摘The chlorine evolution reaction(CER)is a crucial step in the production of chlorine gas and active chlorine by chlor-alkali electrolysis.Currently,the endeavor to fabricate electrodes capable of yielding high current density at minimal overpotential remains a central challenge in advancing the realm of chlorine evolution reactions.Here,we grow TiO_(2)and RuO_(2)on MXene@carbon cloth(CC)through the favorable affinity and induced deposition effect between the surface functional groups of MXene and the metal.A self-supported electrode(RuTiO_(2)/MXene@CC)with strong binding at the electrocatalyst-support interface and weak adhesion at electrocatalyst-bubble interface is constructed.The RuTiO_(2)/MXene@CC can reduce the electron density of RuO_(2)by regulating the electron redistribution at the heterogeneous interface,thus enhancing the adsorption of Cl−.RuTiO_(2)/MXene@CC could achieve a high current density of 1000 mA·cm^(−2)at a small overpotential of 220 mV,superior to commercial dimensionally stable anodes(DSA).This study provides a new strategy for constructing efficient CER catalysts at high current density.
基金part of a research project, PIF 726175Alfaisal University and its Office of Research & Innovation for their continuous support throughout this study。
文摘Direct electrolysis of seawater to produce green hydrogen is a more environmentally friendly process than freshwater electrolysis.The renewable energy sector exhibits tremendous interest in practical seawater electrolysis techniques due to its substantial capacity to mitigate the need for freshwater consumption.With the low catalytic efficiency of the current seawater splitting process and the poor reliability of its operation,the process suffers from severe corrosion caused by chloride ions,as well as anodic competition between oxygen evolution and chlorine oxidation reactions.This review provides an overview of the latest electrocatalyst developments for promoting selectivity and stability in seawater electrolysis.Using the characterization and simulation results,as well as active machine learning,advanced electrocatalytic materials can be designed and developed,a research direction that will become increasingly important in the future.A variety of strategies are discussed in detail for designing advanced electrocatalysts in seawater electrolysis,including the surface protective layer,structural regulation by heteroatom doping and vacancies,porous structure,core-shell construction,and 3D hetero-structure construction to hinder chlorine evolution reactions.Finally,future perspectives and challenges for green hydrogen production from seawater electrolysis are also described.
基金supported by ZiQoo Chemical Co.Ltd.,Japan,and Hydrogen Energy Systems Society of Japan.Feng and Chen gratefully acknowledge the State Scholarship Fund of China Scholarship Council,China.
文摘Earth-abundant seawater resource has become an attractive candidate to produce hydrogen from electrolysis,which is of great significance to realize hydrogen economy and carbon neutrality.Nonetheless,developing highly active and stable electrocatalysts to meet the needs of highly effective seawater splitting is still challenging for the sluggish oxygen evolution dynamics and the existed competitive reaction of chlorine evolution reaction(CER).To this end,some newly-developed electrocatalysts with superior performance,such as noble metals,alloy,transition metals,oxides,carbides,nitrides,phosphides,and so on,have been synthesized for the seawater splitting in recent years.This review starts from the historical background and fundamental mechanisms,and summarizes the most recent progress in the development of seawater electrolysis technologies.Some existing issues in the process of seawater electrolysis are enumerated and the corresponded solutions are presented.The future of hydrogen production from seawater electrolysis,especially the design and synthesis of novel catalysts for seawater electrolysis,is prospected.
基金The work was supported by the National Nature Science Foundation of China(Nos.2193800 and 22078232)the Science and Technology Major Project of Tianjin(Nos.18ZXJMTG00180 and 19ZXNCGX00030).
文摘As an energy-intensive industry,the chlor-alkali process has caused numerous environmental issues due to heavy electricity consumption and pollution.Chlor-alkali industry has been upgraded from mercury,diaphragm electrolytic cell,to ion exchange membrane(IEM)electrolytic cells.However,several challenges,such as the selectivity of the anodic reaction,sluggish kinetics of alkaline hydrogen evolution,degradation of membranes,the reasonable design of electrolytic cell structure,remain to be addressed.For these reasons,this paper mainly reviews the research progress of the chlor-alkali industry from materials to devices,including hydrogen evolution anode,chlorine evolution cathode,IEM,and electrolytic cell system.Finally,the research directions and prospects in the chlor-alkali industry are proposed for its further improvement.
基金supported by the GEONJI Research support programsupported by Basic Science Research through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2021R1I1A1A01050905)+1 种基金supported by grants from the Medical Research Center Program(NRF-2017R1A5A2015061)through the National Research Foundation(NRF),which is funded by the Korean government(MSIP)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future Planning(NRF-2020R1A2B5B01001458)。
文摘Scaled-up industrial water electrolysis equipment that can be used with abundant seawater is key for affordable hydrogen production.The search for highly stable,dynamic,and economical electrocatalysts could have a significant impact on hydrogen commercialization.Herein,we prepared energy-efficient,scalable,and engineering electronic structure modulated Mn-Ni bimetal oxides(Mn_(0.25)Ni_(0.75)O)through simple hydrothermal followed by calcination method.As-optimized Mn_(0.25)Ni_(0.75)O displayed enhanced oxygen and hydrogen evolution reaction(OER and HER)performance with overpotentials of 266 and115 mV at current densities of 10 mA cm^(-2)in alkaline KOH added seawater electrolyte solution.Additionally,Mn-Ni oxide catalytic benefits were attributed to the calculated electronic configurations and Gibbs free energy for OER,and HER values were estimated using first principles calculations.In real-time practical application,we mimicked industrial operating conditions with modified seawater electrolysis using Mn_(0.25)Ni_(0.75)O‖Mn_(0.25)Ni_(0.75)O under various temperature conditions,which performs superior to the commercial IrO_(2)‖Pt-C couple.These findings demonstrate an inexpensive and facile technique for feasible large-scale hydrogen production.
文摘To improve the durability as well as to reduce the cost of anodes, the IrO2＋MnO2 composite coating anodes for NaCIO production were prepared by thermal decomposition. Scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDX）, and X-ray diffraction analysis （XRD） were carried out to investigate the morphologies, element distribution, and microstructure. The anodic polarization curves were employed to study the effect of sintering temperature on the Cl2 evolution reaction （CER） of the electrodes. The accelerated life tests （ALT） and electrochemical impedance spectroscopy measurement （EIS） were utilized to investigate the stability. The rules of NaCIO production were also studied by the static electrolysis experiment. The results indicate that sintering temperature has a significant influence on the CER properties as well as the ALT values of the electrodes. The electrode prepared at 400℃ has the best CER properties and the longest ALT value.
基金the fund(FSU-2020-01)the technical support of AMCC at Khalifa University.
文摘Transition metal based bimetallic oxides are good candidates for electrocatalytic oxygen evolution owing to their variable oxidation states,synergistic effects,good conductivity,convincing electrochemical stability,and low cost.However,these materials are highly susceptible to corrosion during saline seawater electrolysis.This work,for the first time,highlights the role of cerium(Ce)doping in bimetallic strontium cobalt oxide(SrCoO_(x))electrocatalyst for electrochemically stable and corrosion-resistant oxygen evolution reaction(OER)in simulated saline water.The experimental results reveal that 0.5%Ce-doped 5%SrCoO_(x) has the best corrosion resistant ability with respect to the undoped SrCoO_(x) and various other Cedoped samples.The growth of CeO_(2) nanoparticles and the generation of CeO_(x) passivation layer through Ce doping were supposed to block the corrosive ions on the surface,thereby hindering chlorine evolution reaction(CER).The Ce^(3+)ions doped inside the SrCoO_(x) lattice created multiple defects and vacancies which sacrificially facilitate the OER while mitigating the CER.The suppression of corrosive reactions was indicated through low corrosion current(−1.10μA·cm^(−2))and high corrosion potential(0.90 V vs.RHE)values suggesting slowest corrosion rate and least tendency towards CER in 0.5%Ce-doped 5%SrCoO_(x).Consequently,it demonstrated the least Tafel slope of 81.7 mV·dec^(−1) in saline OER electrolysis with respect to the 121.0 mV·dec^(−1) was obtained for undoped 5%SrCoO_(x).Moreover,the electrochemical stability demonstrated in chronoamperometric OER for 45 h and the cyclic voltammetry(500 cycles)confirmed that 0.5%Ce-doped SrCoO_(x) electrocatalyst possesses enhanced anticorrosive properties,which was further supported by post-use linear sweep voltammetry,cyclic voltammetry,and X-ray diffraction analyses.Linear polarization resistance study was also employed on the seawater sample,collected locally,to assess the validity of the present work in real marine systems.In view of the observed results,this work can open an alternate pathway to investigate various transition metal oxide systems as potential corrosion resistant electrocatalysts for seawater.
基金supported by the National Natural Science Foundation of China(Grant Nos.52402273,52272222,52072197)Youth Innovation Team Development Program of Shandong Higher Education Institutions(Grant No.2022KJ155)Taishan Scholar Young Talent Program(Grant No.tsqn201909114)。
文摘The chlorine evolution reaction(CER)serves as the cornerstone and crucial step in the conversion of chloride ions to chlorine gas,while accompanied by the occurrence of the oxygen evolution reaction(OER)in practical processes that lead to difficulty in achieving the purity requirements of the product Cl_(2)for industrial applications.Pd-doped Co_(3)O_(4) nanoneedles(Pd-Co_(3)O_(4)NNs)were synthesized via hydrothermal-calcination methods.Pd sites induce electron delocalization,creating asymmetric active Co sites in Co_(3)O_(4),enhancing CER performance.The unique nanoneedle arrays of the designed catalysts increase the number of exposed active sites,facilitating electron transfer and endowing the Pd-Co_(3)O_(4)NNs with a tip catalytic effect,further optimizing the catalytic reaction kinetics of CER with an overpotential of 118 mV at 100 mA cm^(-2)and a Tafel slope of 53.93 mV dec^(-1).The density functional theory(DFT)calculations reveal that Pd incorporation at octahedral sites triggers charge redistribution and d-band center downshift,weakening intermediate adsorption and sustaining catalytic activity.This work offers new insights into noble-metal-doped spinel oxides,highlighting their potential for industrial applications.
基金This work is supported by ZiQoo Chemical Co.Ltd.,Japan,and Hydrogen Energy Systems Society of Japan.Chen and Feng gratefully acknowledge the State Scholarship Fund of China Scholarship Council,China.Kitiphatpiboon gratefully acknowledges MEXT of Japan for the scholarship,Japan.
文摘Direct electrolytic splitting of seawater for the production of H2 using ocean energy is a promising technology that can help achieve carbon neutrality.However,owing to the high concentrations of chlorine ions in seawater,the chlorine evolution reaction always competes with the oxygen evolution reaction(OER)at the anode,and chloride corrosion occurs on both the anode and cathode.Thus,effective electrocatalysts with high selectivity toward the OER and excellent resistance to chloride corrosion should be developed.In this critical review,we focus on the prospects of state-of-the-art metal-oxide electrocatalysts,including noble metal oxides,non-noble metal oxides and their compounds,and spinel-and perovskite-type oxides,for seawater splitting.We elucidate their chemical properties,excellent OER selectivity,outstanding anti-chlorine-corrosion performance,and reaction mechanisms.In particular,we review metal oxides that operate at high current densities,near industrial application levels,based on special catalyst design strategies.
基金supported by the National Key Research and De-velopment Project of China(2022YFE0113800)National Natural Sci-ence Foundation of China(21905246,51972286,and 22005268)+2 种基金Zhe-jiang Provincial Natural Science Foundation of China(LZ21E020003,LR19E020003,LQ21E020004,and LQ20B010011)Fundamental Re-search Funds for the Provincial Universities of Zhejiang(RF-B-2020004)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2020R01002).
文摘The direct electrolytic splitting of abundant seawater instead of scarce freshwater is an ideal strategy for producing clean and renewable hydrogen(H 2)fuels.The oxygen evolution reaction(OER)is a vital half-reaction that occurs during electrochemical seawater splitting.However,OER suffers from sluggish four-electron transfer kinetics and competitive chlorine evolution reactions in seawater.Noble metal-based catalysts such as IrO_(2) and RuO_(2) are considered to have state-of-the-art OER electrocatalytic activity,but the low reserves and high prices of these noble metals significantly limit their large-scale application.Recently,efforts have been made to explore efficient,robust,and anti-chlorine-corrosion non-noble-metal OER electrocatalysts for seawater splitting such as oxides,hydroxides,phosphides,nitrides,chalcogenides,alloys,and composites.An in-depth understanding of the fundamentals of seawater electrolysis and the design principle of electrode materials is important for promoting seawater-splitting technology.In this review,we first introduce fundamental reactions in seawater electrolytes.Subsequently,construction strategies for OER electrocatalysts for seawater splitting are introduced.Finally,present challenges and perspectives regarding non-noble-metal OER electrocatalysts for commercial H 2 production by seawater splitting are discussed.
