Iridium(Ir)-based materials are the only commercializable class of anode electrocatalysts for acidic oxygen evolution reaction(OER)in proton exchange membrane water electrolyzers(PEMWE).Intending to large-scale implem...Iridium(Ir)-based materials are the only commercializable class of anode electrocatalysts for acidic oxygen evolution reaction(OER)in proton exchange membrane water electrolyzers(PEMWE).Intending to large-scale implement of PEMWE,it is urgent to improve their OER performances for reducing the usage of high-cost Ir element.Herein,we report an elaborate synthesis of ultrathin Ir/WO_(x)hybrid nanosheets equipped with abundant 2D-confined heterointerfaces(denoted as Ir/WO_(x)NSs),which are composed of ultrathin Ir nanograins embedded in amorphous WO_(x)matrix,to substantially enhance the acidic OER.The Ir/WO_(x)NSs achieve a notable mass activity of 2.34 A mg Ir^(−1)at an overpotential of 300 mV,which is approximately 11.1 and 9.8 times higher than those of Ir NSs and commercial Ir/C,respectively.The 2D-confined interactions between crystalline Ir nanograins and amorphous WO_(x)matrix establish synergistic bifunctional sites and efficient charge transfer interfaces,which effectively accelerate the initial hydrolysis dissociation step.Moreover,on interfacial Ir atoms,the adsorption of*O and subsequent formation of*OOH intermediates are thermodynamically facilitated,making the OER process more favorable through the adsorbate evolution mechanism.Finally,the Ir/WO_(x)NSs based PEMWE demonstrates a low cell voltage of only 1.71 V to deliver 1.0 A cm^(−2)current density as well as an outstanding long-term durability,realizing efficient and stable green hydrogen production.This work highlights the engineering of 2D-confined metal-oxide interfacial electrocatalysts for efficient energy conversion applications.展开更多
Proton exchange membrane water electrolyzer(PEMWE)represents a highly promising technology for renewable hydrogen generation,urgently demanding low-cost,efficient,and robust anode oxygen evolution reaction(OER)electro...Proton exchange membrane water electrolyzer(PEMWE)represents a highly promising technology for renewable hydrogen generation,urgently demanding low-cost,efficient,and robust anode oxygen evolution reaction(OER)electrocatalysts in acidic media.Over the past decade(mainly from 2016 onwards),low-Ir/Ru perovskite oxides have emerged as promising candidate materials for acidic OER electrocatalysis owing to their flexible element compositions and crystal structures,which can evidently reduce the noble-metal content and meanwhile significantly promote electrocatalytic performance.In this review,the current research progress in low-Ir/Ru perovskite oxides for acidic OER electrocatalysis is comprehensively summarized.Initially,we present a brief introduction to general issues relevant to acidic OER catalyzed by low-Ir/Ru perovskite oxides,such as the actual active species,OER mechanisms,inverse activity-stability relationship,and performance evaluation metrics.Subsequently,we present a thorough overview of various low-Ir/Ru perovskite oxides for acidic OER electrocatalysis,including single perovskites,double perovskites,triple perovskites,quadruple perovskites,Ruddlesden-Popper perovskites,and other complex perovskite-derived oxides,with emphasis on the intrinsic factors contributing to their exceptional performance and structure-property-performance correlation.Finally,remaining challenges and some promising insights to inspire future studies in this exciting field are provided.展开更多
The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct ...The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.展开更多
The oxygen evolution reaction(OER)electrocatalysts,which can keep active for a long time in acidic media,are of great significance to proton exchange membrane water electrolyzers.Here,Ru-Co_(3)O_(4)electrocatalysts wi...The oxygen evolution reaction(OER)electrocatalysts,which can keep active for a long time in acidic media,are of great significance to proton exchange membrane water electrolyzers.Here,Ru-Co_(3)O_(4)electrocatalysts with transition metal oxide Co_(3)O_(4)as matrix and the noble metal Ru as doping element have been prepared through an ion exchange–pyrolysis process mediated by metal-organic framework,in which Ru atoms occupy the octahedral sites of Co_(3)O_(4).Experimental and theoretical studies show that introduced Ru atoms have a passivation effect on lattice oxygen.The strong coupling between Ru and O causes a negative shift in the energy position of the O p-band centers.Therefore,the bonding activity of oxygen in the adsorbed state to the lattice oxygen is greatly passivated during the OER process,thus improving the stability of matrix material.In addition,benefiting from the modulating effect of the introduced Ru atoms on the metal active sites,the thermodynamic and kinetic barriers have been significantly reduced,which greatly enhances both the catalytic stability and reaction efficiency of Co_(3)O_(4).展开更多
Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru ...Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru dissolution during OER compromises the activity and stability.Amorphous materials have been identified as a viable strategy to promote the stability of RuO_(2)in acidic OER applications.This study reported a nanoporous amorphous-rich RuMnO_(x)(A-RuMnO_(x))aerogel for efficient and stable acidic OER.Compared with highly crystalline RuMnO_(x),the weakened Ru–O covalency of A-RuMnO_(x)by forming amorphous structure is favorable to inhibiting the oxidation of lattice oxygen.Meanwhile,this also optimizes the electronic structure of Ru sites from overoxidation and reduces the reaction energy barrier of the rate-determining step.As a result,A-RuMnO_(x)aerogel exhibits an ultra-low overpotential of 145 mV at 10 mA cm^(-2)and durability exceeding 100 h,as well as high mass activity up to 153 mA mg^(-1)_(Ru)at 1.5 V vs.reversible hydrogen electrode(RHE).This work provides valuable guidance for preparing highly active and stable Ru-based catalysts for acidic OER.展开更多
The persistent stability of ruthenium dioxide(RuO_(2))in acidic oxygen evolution reactions(OER)is compromised by the involvement of lattice oxygen(LO)and metal dissolution during the OER process.Heteroatom doping has ...The persistent stability of ruthenium dioxide(RuO_(2))in acidic oxygen evolution reactions(OER)is compromised by the involvement of lattice oxygen(LO)and metal dissolution during the OER process.Heteroatom doping has been recognized as a viable strategy to foster the stability of RuO_(2)for acidic OER applications.This study presented an ion that does not readily gain or lose electrons,Ba^(2+),into RuO_(2)(Ba-RuO_(2))nanosheet(NS)catalyst that increased the number of exposed active sites,achieving a current density of 10 mA/cm^(2)with an overpotential of only 229 mV and sustaining this output for over 250 h.According to density functional theory(DFT)and X-ray absorption spectroscopy,Ba doping resulted in a longer Ru-O bond length,which in turn diminished the covalency of the bond.This alteration curtailed the involvement of LO and the dissolution of ruthenium(Ru),thereby markedly improving the durability of the catalyst over extended periods.Additionally,attenuated total reflectance-surface enhanced infrared absorption spectroscopy analysis substantiated that the OER mechanism shifted from a LO-mediated pathway to an adsorbate evolution pathway due to Ba doping,thereby circumventing Ru over-oxidation and further enhancing the stability of RuO_(2).Furthermore,DFT findings uncovered that Ba doping optimizes the adsorption energy of intermediates,thus enhancing the OER activity in acidic environments.This study offers a potent strategy to guide future developments on Ru-based oxide catalysts'stability in an acidic environment.展开更多
The oxygen evolution reaction(OER)is critical for sustainable energy technologies,including proton exchange membrane water electrolyzers(PEMWEs)and metal-air batteries.However,its implementation in acidic media remain...The oxygen evolution reaction(OER)is critical for sustainable energy technologies,including proton exchange membrane water electrolyzers(PEMWEs)and metal-air batteries.However,its implementation in acidic media remains constrained by sluggish kinetics,high energy barriers,and reliance on scarce noble-metal catalysts.Cobalt-based single-atom catalysts(Co-SACs)have emerged as a breakthrough solution,combining exceptional catalytic activity,stability,and atomic utilization efficiency.Its superior acidic OER performance stems from the electronic structure of low-spin Co^(3+)centers,which optimize t_(2g)–πorbital interactions with oxygen intermediates.This configuration promotes efficient surface reconstruction and thermodynamically favorable adsorption of OER species,accelerating reaction kinetics.Tailored coordination environments,engineered via supports like nitrogen-doped carbons,graphene,or metal oxides,can further modulate Co electronic and spin states,enhancing activity and durability.This review systematically analyzes advancements in Co-SAC design,elucidating correlations between atomic coordination,electronic properties,and catalytic mechanisms.Advanced synthesis methods and characterization tools are evaluated to discuss structure-activity relationships of Co-SAC.Finally,we address current challenges and future research directions that involve computational modeling,multi-metallic SAC architectures,and operando techniques to guide the rational design of high-performance Co-SACs.Addressing these challenges will accelerate the commercialization of PEMWEs for cost-effective green hydrogen production.展开更多
The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-medi...The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-mediated mechanism(LOM)has been identified as the major contributor to the fast performance degradation,impeding lattice oxygen diffusion to inhibit lattice oxygen participation is imperative,yet remains challenging due to the lack of efficient approaches.Herein,we strategically regulate the bonding nature of Ru–O towards suppressed LOM via Ru-based high-entropy oxide(HEO)construction.The lattice disorder in HEOs is believed to increase migration energy barrier of lattice oxygen.As a result,the screened Ti_(23)Nb_(9)Hf_(13)W_(12)Ru_(43)O_(x) exhibits 11.7 times slower lattice oxygen diffusion rate,84%reduction in LOM ratio,and 29 times lifespan extension compared with the state-of-the-art RuO_(2) catalyst.Our work opens up a feasible avenue to constructing stabilized Ru-based OER catalysts towards scalable application.展开更多
The design of highly active and stable catalysts for the oxygen evolution reaction(OER) in acidic media has become an attractive research area for the development of energy conversion and storage technologies. However...The design of highly active and stable catalysts for the oxygen evolution reaction(OER) in acidic media has become an attractive research area for the development of energy conversion and storage technologies. However, progress in this area has been limited by the poor understanding of the dynamic active structure of catalysts under realistic OER conditions. Here, an atomic Co-doped nanoporous Ru O_(2)electrocatalyst, which exhibited excellent OER activity and stability in acidic conditions, was synthesized through annealing and etching of a nanoporous Co-Ru alloy. Operando X-ray absorption spectroscopy results confirmed that the etching strategy produced abundant oxygen vacancies around the metal centers in the atomic Co-doped nanoporous Ru O_(2)electrocatalyst. These vacancies created contracted metaloxygen ligand bonds under realistic OER conditions. The dynamic structural evolution of the synthesized electrocatalyst allowed them to experience lower kinetic barriers during OER catalysis, resulting in enhanced catalytic activity and stability.This study also provided atomic details on the active structure of the electrocatalyst and the influence of their structural evolution on OER activity.展开更多
The development of high-performance oxygen evolution reaction catalysts with low iridium content is the key to the scale-up of proton exchange membrane water electrolyzer(PEMWE)for green hydrogen production.Single-sit...The development of high-performance oxygen evolution reaction catalysts with low iridium content is the key to the scale-up of proton exchange membrane water electrolyzer(PEMWE)for green hydrogen production.Single-site electrocatalysts with maximized atomic efficiency are held as promising candidates but still suffer from inadequate activity and stability in practical electrolyzer due to the low site density.Here,we proposed a NaNO_(3)-assistant thermal decomposition strategy for the preparation of high-density Ir single sites on MnO_(2)substrate(NaNO_(3)-H-Ir-MnO_(2)).Direct spectroscopic evidence suggests the inclusion of NaNO_(3)accelerates the transformation of Ir-Cl to Ir-O coordination,thus generating uniform dispersed high-density Ir single sites in the products.The optimized H-Ir-MnO_(2)demonstrates not only high intrinsic activity in a three-electrode set-up but also boosted performance in scalable PEMWE,requiring a cell voltage of only 1.74 V to attain a high current density of 2 A cm^(-2)at a low Ir loading of 0.18 mgIr cm^(-2).This work offers a new insight for enhancing the industrial practicality of Ir-based single site catalysts.展开更多
The electrocatalysis of oxygen evolution reaction(OER)plays a key role in clean energy storage and transfer.Nonetheless,the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder pra...The electrocatalysis of oxygen evolution reaction(OER)plays a key role in clean energy storage and transfer.Nonetheless,the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder practical applications such as electrolyzer compatible with the powerful proton exchange membrane and biohybrid fuel production.Here,we report a borondoped ruthenium dioxide electrocatalyst(B-RuO_(2))fabricated by a facile boric acid assisted strategy which demonstrates excellent acidic and neutral OER performances.Density functional theory calculations and advanced characterizations reveal that the boron species form an anomalous B–O covalent bonding with the oxygen atoms of RuO_(2)and expose the fully coordinately bridge ruthenium site(Ru-bri site),which seems like a switch that turns on the inactive Ru-bri site into OER-active,resulting in more exposed active sites,modified electronic structure,and optimized binding energy of intermediates.Thus,the B-RuO_(2)exhibits an ultralow overpotential of 200 mV at 10 mA/cm^(2)and maintains excellent stability compared to commercial RuO_(2)in 0.5 M sulfuric acid.Moreover,the superior performance is as well displayed in neutral electrolyte,surpassing most previously reported catalysts.展开更多
The acidic oxygen evolution reaction(OER)is central to water electrolysis using proton‐exchange membranes.However,even as benchmark catalysts in the acidic OER,Ru‐based catalysts still suffer from sluggish kinetics ...The acidic oxygen evolution reaction(OER)is central to water electrolysis using proton‐exchange membranes.However,even as benchmark catalysts in the acidic OER,Ru‐based catalysts still suffer from sluggish kinetics owing to the scaling relationship that arises from the traditional concerted proton‐electron transfer(CPET)process.Motivated by the knowledge that a charged surface may be favorable for accelerating the OER kinetics,we posited the incorporation of elements with pseudocapacitive properties into Ru‐based catalysts.Herein,we report a RuPbOx electrocatalyst for efficient and stable water oxidation in acid with a low overpotential of 191 mV to reach 10 mA cm^(−2) and a low Tafel slope of 39 mV dec^(−1).The combination of electrochemical analysis,X‐ray photoelectron spectroscopy,and in situ Raman spectroscopy demonstrated that the improved OER kinetics was associated with the formation of superoxide precursors on the strongly charged surface after Pb incorporation,indicating a non‐concerted proton‐electron transfer mechanism for the OER on RuPbOx.展开更多
The development of a highly efficient noniridium-based oxygen evolution reaction catalyst is the key to realizing large-scale commercial application of the proton-exchange membrane water electrolyzer.RuO_(2)is the mos...The development of a highly efficient noniridium-based oxygen evolution reaction catalyst is the key to realizing large-scale commercial application of the proton-exchange membrane water electrolyzer.RuO_(2)is the most promising alternative to IrO_(2),but if usually suffers from lattice-oxygenmediated corrosion and sluggish proton transfer kinetics under acidic media.Herein,we propose an effective strategy of embedding RuO_(2)nanoparticles into a N-doped carbon support,termed as RuO_(2)-NC,to simultaneously prevent Ru dissolution and accelerate the bridging-oxygen-assisted deprotonation process.The obtained RuO_(2)-NC electrocatalyst presents high activity with an overpotential of 159 mV to reach 10 mA cm^(−2) and remarkable stability for over 240 h.Structural investigation and theoretical calculations reveal that the electron-rich NC substrate,as an electron donor,provides a buffered charge compensation to protect RuO_(2)from excessive oxidation and lattice oxygen loss by switching into a conventional adsorbate evolution mechanism(AEM).More importantly,the activated bridging oxygen(Obri)sites can facilitate the deprotonation of*OOH intermediates,leading to an optimized bridging-oxygen-assisted deprotonation AEM pathway.展开更多
Proton exchange membrane water electrolyzer(PEMWE)technology is regarded as one of the most promising methods for green hydrogen generation.The oxygen evolution reaction(OER)at the anode is the primary bottleneck prev...Proton exchange membrane water electrolyzer(PEMWE)technology is regarded as one of the most promising methods for green hydrogen generation.The oxygen evolution reaction(OER)at the anode is the primary bottleneck preventing the industrial-scale application of PEMWEs due to its sluggish kinetics,and it presently relies upon electrocatalysts that use scarce,costly Ru and Ir.In addition,most of the Ru-and Ir-based electrocatalysts developed to date need high noble metal loading and present good activity only at low current density for a short period.In this review,we systematically elaborate upon various effective strategies for modulating Ruand Ir-based catalysts to achieve large current density,high stability,and high atom economy,including singleatom designs,heteroatom doping,defect/vacancy creation,alloying,and heterojunction engineering.The structure–performance relationships of OER catalysts synthesized using different strategies are elucidated,along with the importance of substrate materials.We conclude by discussing the remaining challenges and future prospects for OER electrocatalysts in acid.展开更多
基金supported by the National Natural Science Foundation of China(U24A20563,22171093,22201085)the Natural Science Foundation of Fujian Province(2022J02008)the Scientific Research Funds of Huaqiao University.
文摘Iridium(Ir)-based materials are the only commercializable class of anode electrocatalysts for acidic oxygen evolution reaction(OER)in proton exchange membrane water electrolyzers(PEMWE).Intending to large-scale implement of PEMWE,it is urgent to improve their OER performances for reducing the usage of high-cost Ir element.Herein,we report an elaborate synthesis of ultrathin Ir/WO_(x)hybrid nanosheets equipped with abundant 2D-confined heterointerfaces(denoted as Ir/WO_(x)NSs),which are composed of ultrathin Ir nanograins embedded in amorphous WO_(x)matrix,to substantially enhance the acidic OER.The Ir/WO_(x)NSs achieve a notable mass activity of 2.34 A mg Ir^(−1)at an overpotential of 300 mV,which is approximately 11.1 and 9.8 times higher than those of Ir NSs and commercial Ir/C,respectively.The 2D-confined interactions between crystalline Ir nanograins and amorphous WO_(x)matrix establish synergistic bifunctional sites and efficient charge transfer interfaces,which effectively accelerate the initial hydrolysis dissociation step.Moreover,on interfacial Ir atoms,the adsorption of*O and subsequent formation of*OOH intermediates are thermodynamically facilitated,making the OER process more favorable through the adsorbate evolution mechanism.Finally,the Ir/WO_(x)NSs based PEMWE demonstrates a low cell voltage of only 1.71 V to deliver 1.0 A cm^(−2)current density as well as an outstanding long-term durability,realizing efficient and stable green hydrogen production.This work highlights the engineering of 2D-confined metal-oxide interfacial electrocatalysts for efficient energy conversion applications.
基金supported by the Natural Science Foundation for Young Scholars of Jiangsu Province(No.BK20220879)the National Natural Science Foundation of China(No.22209072 and No.22479075)+1 种基金the Open Research Fund of Guangdong Advanced Carbon Materials Co.,Ltd(No.Kargen-2024B0801)the Jiangsu Specially-Appointed Professors and National Natural Science Fund of China for Excellent Young Scientists Fund Program(Overseas)。
文摘Proton exchange membrane water electrolyzer(PEMWE)represents a highly promising technology for renewable hydrogen generation,urgently demanding low-cost,efficient,and robust anode oxygen evolution reaction(OER)electrocatalysts in acidic media.Over the past decade(mainly from 2016 onwards),low-Ir/Ru perovskite oxides have emerged as promising candidate materials for acidic OER electrocatalysis owing to their flexible element compositions and crystal structures,which can evidently reduce the noble-metal content and meanwhile significantly promote electrocatalytic performance.In this review,the current research progress in low-Ir/Ru perovskite oxides for acidic OER electrocatalysis is comprehensively summarized.Initially,we present a brief introduction to general issues relevant to acidic OER catalyzed by low-Ir/Ru perovskite oxides,such as the actual active species,OER mechanisms,inverse activity-stability relationship,and performance evaluation metrics.Subsequently,we present a thorough overview of various low-Ir/Ru perovskite oxides for acidic OER electrocatalysis,including single perovskites,double perovskites,triple perovskites,quadruple perovskites,Ruddlesden-Popper perovskites,and other complex perovskite-derived oxides,with emphasis on the intrinsic factors contributing to their exceptional performance and structure-property-performance correlation.Finally,remaining challenges and some promising insights to inspire future studies in this exciting field are provided.
基金supported by the Taishan Scholar Program of Shandong Province,China(tsqn202211162)the National Natural Science Foundation of China(22102079)the Natural Science Foundation of Shandong Province of China(ZR2021YQ10,ZR2022QB163)。
文摘The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.
基金the National Natural Science Foundation of China(Nos.12025503,U23B2072,and 12105208)。
文摘The oxygen evolution reaction(OER)electrocatalysts,which can keep active for a long time in acidic media,are of great significance to proton exchange membrane water electrolyzers.Here,Ru-Co_(3)O_(4)electrocatalysts with transition metal oxide Co_(3)O_(4)as matrix and the noble metal Ru as doping element have been prepared through an ion exchange–pyrolysis process mediated by metal-organic framework,in which Ru atoms occupy the octahedral sites of Co_(3)O_(4).Experimental and theoretical studies show that introduced Ru atoms have a passivation effect on lattice oxygen.The strong coupling between Ru and O causes a negative shift in the energy position of the O p-band centers.Therefore,the bonding activity of oxygen in the adsorbed state to the lattice oxygen is greatly passivated during the OER process,thus improving the stability of matrix material.In addition,benefiting from the modulating effect of the introduced Ru atoms on the metal active sites,the thermodynamic and kinetic barriers have been significantly reduced,which greatly enhances both the catalytic stability and reaction efficiency of Co_(3)O_(4).
基金financial support from the National Natural Science Foundation of China(22478278,22308246)the Central Government Guides the Local Science and Technology Development Special Fund(YDZJSX20231A015)the Fundamental Research Program of Shanxi Province(202203021212266)。
文摘Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru dissolution during OER compromises the activity and stability.Amorphous materials have been identified as a viable strategy to promote the stability of RuO_(2)in acidic OER applications.This study reported a nanoporous amorphous-rich RuMnO_(x)(A-RuMnO_(x))aerogel for efficient and stable acidic OER.Compared with highly crystalline RuMnO_(x),the weakened Ru–O covalency of A-RuMnO_(x)by forming amorphous structure is favorable to inhibiting the oxidation of lattice oxygen.Meanwhile,this also optimizes the electronic structure of Ru sites from overoxidation and reduces the reaction energy barrier of the rate-determining step.As a result,A-RuMnO_(x)aerogel exhibits an ultra-low overpotential of 145 mV at 10 mA cm^(-2)and durability exceeding 100 h,as well as high mass activity up to 153 mA mg^(-1)_(Ru)at 1.5 V vs.reversible hydrogen electrode(RHE).This work provides valuable guidance for preparing highly active and stable Ru-based catalysts for acidic OER.
基金supported by Young Project of Education Department in Guizhou Province(No.2022099)the Natural Science Special of Guizhou University(No.X202220 Special Post A)the National Natural Science Foundation of China(Grant No.22208071)。
文摘The persistent stability of ruthenium dioxide(RuO_(2))in acidic oxygen evolution reactions(OER)is compromised by the involvement of lattice oxygen(LO)and metal dissolution during the OER process.Heteroatom doping has been recognized as a viable strategy to foster the stability of RuO_(2)for acidic OER applications.This study presented an ion that does not readily gain or lose electrons,Ba^(2+),into RuO_(2)(Ba-RuO_(2))nanosheet(NS)catalyst that increased the number of exposed active sites,achieving a current density of 10 mA/cm^(2)with an overpotential of only 229 mV and sustaining this output for over 250 h.According to density functional theory(DFT)and X-ray absorption spectroscopy,Ba doping resulted in a longer Ru-O bond length,which in turn diminished the covalency of the bond.This alteration curtailed the involvement of LO and the dissolution of ruthenium(Ru),thereby markedly improving the durability of the catalyst over extended periods.Additionally,attenuated total reflectance-surface enhanced infrared absorption spectroscopy analysis substantiated that the OER mechanism shifted from a LO-mediated pathway to an adsorbate evolution pathway due to Ba doping,thereby circumventing Ru over-oxidation and further enhancing the stability of RuO_(2).Furthermore,DFT findings uncovered that Ba doping optimizes the adsorption energy of intermediates,thus enhancing the OER activity in acidic environments.This study offers a potent strategy to guide future developments on Ru-based oxide catalysts'stability in an acidic environment.
基金supported by the Beijing-Tianjin-Hebei Fundamental Research Cooperation Project(No.B2024202090)Sponsored by CNPC Innovation Found(No.2024DQ02-0311)We also thank the Haihe Laboratory of Sustainable Chemical Transformations(No.24HHWCSS00009)for financial support on this work.
文摘The oxygen evolution reaction(OER)is critical for sustainable energy technologies,including proton exchange membrane water electrolyzers(PEMWEs)and metal-air batteries.However,its implementation in acidic media remains constrained by sluggish kinetics,high energy barriers,and reliance on scarce noble-metal catalysts.Cobalt-based single-atom catalysts(Co-SACs)have emerged as a breakthrough solution,combining exceptional catalytic activity,stability,and atomic utilization efficiency.Its superior acidic OER performance stems from the electronic structure of low-spin Co^(3+)centers,which optimize t_(2g)–πorbital interactions with oxygen intermediates.This configuration promotes efficient surface reconstruction and thermodynamically favorable adsorption of OER species,accelerating reaction kinetics.Tailored coordination environments,engineered via supports like nitrogen-doped carbons,graphene,or metal oxides,can further modulate Co electronic and spin states,enhancing activity and durability.This review systematically analyzes advancements in Co-SAC design,elucidating correlations between atomic coordination,electronic properties,and catalytic mechanisms.Advanced synthesis methods and characterization tools are evaluated to discuss structure-activity relationships of Co-SAC.Finally,we address current challenges and future research directions that involve computational modeling,multi-metallic SAC architectures,and operando techniques to guide the rational design of high-performance Co-SACs.Addressing these challenges will accelerate the commercialization of PEMWEs for cost-effective green hydrogen production.
基金The authors thank the National Key R&D Program of China(No.2021YFB4000200)the National Natural Science Foundation of China(No.22232004)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21090400)the Jilin Province Science and Technology Development Program(Nos.20210301008GX,YDZJ202202CXJD011,and 20210502002ZP)for financial support.
文摘The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-mediated mechanism(LOM)has been identified as the major contributor to the fast performance degradation,impeding lattice oxygen diffusion to inhibit lattice oxygen participation is imperative,yet remains challenging due to the lack of efficient approaches.Herein,we strategically regulate the bonding nature of Ru–O towards suppressed LOM via Ru-based high-entropy oxide(HEO)construction.The lattice disorder in HEOs is believed to increase migration energy barrier of lattice oxygen.As a result,the screened Ti_(23)Nb_(9)Hf_(13)W_(12)Ru_(43)O_(x) exhibits 11.7 times slower lattice oxygen diffusion rate,84%reduction in LOM ratio,and 29 times lifespan extension compared with the state-of-the-art RuO_(2) catalyst.Our work opens up a feasible avenue to constructing stabilized Ru-based OER catalysts towards scalable application.
基金the support from the National Natural Science Foundation of China (51771072)the Outstanding Youth Scientist Foundation of Hunan Province (2020JJ2006)+1 种基金the Fundamental Research Funds for the Central Universitiesthe State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Independent Research Project (71860007)。
文摘The design of highly active and stable catalysts for the oxygen evolution reaction(OER) in acidic media has become an attractive research area for the development of energy conversion and storage technologies. However, progress in this area has been limited by the poor understanding of the dynamic active structure of catalysts under realistic OER conditions. Here, an atomic Co-doped nanoporous Ru O_(2)electrocatalyst, which exhibited excellent OER activity and stability in acidic conditions, was synthesized through annealing and etching of a nanoporous Co-Ru alloy. Operando X-ray absorption spectroscopy results confirmed that the etching strategy produced abundant oxygen vacancies around the metal centers in the atomic Co-doped nanoporous Ru O_(2)electrocatalyst. These vacancies created contracted metaloxygen ligand bonds under realistic OER conditions. The dynamic structural evolution of the synthesized electrocatalyst allowed them to experience lower kinetic barriers during OER catalysis, resulting in enhanced catalytic activity and stability.This study also provided atomic details on the active structure of the electrocatalyst and the influence of their structural evolution on OER activity.
文摘The development of high-performance oxygen evolution reaction catalysts with low iridium content is the key to the scale-up of proton exchange membrane water electrolyzer(PEMWE)for green hydrogen production.Single-site electrocatalysts with maximized atomic efficiency are held as promising candidates but still suffer from inadequate activity and stability in practical electrolyzer due to the low site density.Here,we proposed a NaNO_(3)-assistant thermal decomposition strategy for the preparation of high-density Ir single sites on MnO_(2)substrate(NaNO_(3)-H-Ir-MnO_(2)).Direct spectroscopic evidence suggests the inclusion of NaNO_(3)accelerates the transformation of Ir-Cl to Ir-O coordination,thus generating uniform dispersed high-density Ir single sites in the products.The optimized H-Ir-MnO_(2)demonstrates not only high intrinsic activity in a three-electrode set-up but also boosted performance in scalable PEMWE,requiring a cell voltage of only 1.74 V to attain a high current density of 2 A cm^(-2)at a low Ir loading of 0.18 mgIr cm^(-2).This work offers a new insight for enhancing the industrial practicality of Ir-based single site catalysts.
基金the National Key Research and Development Program of China(No.2020YFA0405800)the National Natrual Science Foundation of China(Nos.U1932201,U2032113,and 22075264)+2 种基金CAS Collaborative Innovation Program of Hefei Science Center(No.2020HSC-CIP002)CAS Interdisciplinary Innovation Team,and USTC Research Funds of the Double First-Class Initiative(No.YD2310002003)L.S.also thanks the financial support from State Key Laboratory of Inorganic Synthesis and Preparative Chemistry,College of Chemistry,Jilin University.
文摘The electrocatalysis of oxygen evolution reaction(OER)plays a key role in clean energy storage and transfer.Nonetheless,the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder practical applications such as electrolyzer compatible with the powerful proton exchange membrane and biohybrid fuel production.Here,we report a borondoped ruthenium dioxide electrocatalyst(B-RuO_(2))fabricated by a facile boric acid assisted strategy which demonstrates excellent acidic and neutral OER performances.Density functional theory calculations and advanced characterizations reveal that the boron species form an anomalous B–O covalent bonding with the oxygen atoms of RuO_(2)and expose the fully coordinately bridge ruthenium site(Ru-bri site),which seems like a switch that turns on the inactive Ru-bri site into OER-active,resulting in more exposed active sites,modified electronic structure,and optimized binding energy of intermediates.Thus,the B-RuO_(2)exhibits an ultralow overpotential of 200 mV at 10 mA/cm^(2)and maintains excellent stability compared to commercial RuO_(2)in 0.5 M sulfuric acid.Moreover,the superior performance is as well displayed in neutral electrolyte,surpassing most previously reported catalysts.
文摘The acidic oxygen evolution reaction(OER)is central to water electrolysis using proton‐exchange membranes.However,even as benchmark catalysts in the acidic OER,Ru‐based catalysts still suffer from sluggish kinetics owing to the scaling relationship that arises from the traditional concerted proton‐electron transfer(CPET)process.Motivated by the knowledge that a charged surface may be favorable for accelerating the OER kinetics,we posited the incorporation of elements with pseudocapacitive properties into Ru‐based catalysts.Herein,we report a RuPbOx electrocatalyst for efficient and stable water oxidation in acid with a low overpotential of 191 mV to reach 10 mA cm^(−2) and a low Tafel slope of 39 mV dec^(−1).The combination of electrochemical analysis,X‐ray photoelectron spectroscopy,and in situ Raman spectroscopy demonstrated that the improved OER kinetics was associated with the formation of superoxide precursors on the strongly charged surface after Pb incorporation,indicating a non‐concerted proton‐electron transfer mechanism for the OER on RuPbOx.
基金financially supported by the National Natural Science Foundation of China(grant nos.22272121 and 21972107)We thank the core facility of Wuhan University for the measurement of XPS.We also thank the Core Research Facilities of the College of Chemistry and Molecular Sciences for the measurement of TEM.DFT calculations in this paper have been done on the supercomputing system in the Supercomputing Center of Wuhan University.W.L.conceived and supervised the project.H.J.and Z.L.synthesized the electrocatalysts and performed the catalytic tests and characterization.J.Z.performed the DFT calculations.W.L.and H.J.wrote the manuscript.All the authors discussed the results and assisted during the manuscript preparation.
文摘The development of a highly efficient noniridium-based oxygen evolution reaction catalyst is the key to realizing large-scale commercial application of the proton-exchange membrane water electrolyzer.RuO_(2)is the most promising alternative to IrO_(2),but if usually suffers from lattice-oxygenmediated corrosion and sluggish proton transfer kinetics under acidic media.Herein,we propose an effective strategy of embedding RuO_(2)nanoparticles into a N-doped carbon support,termed as RuO_(2)-NC,to simultaneously prevent Ru dissolution and accelerate the bridging-oxygen-assisted deprotonation process.The obtained RuO_(2)-NC electrocatalyst presents high activity with an overpotential of 159 mV to reach 10 mA cm^(−2) and remarkable stability for over 240 h.Structural investigation and theoretical calculations reveal that the electron-rich NC substrate,as an electron donor,provides a buffered charge compensation to protect RuO_(2)from excessive oxidation and lattice oxygen loss by switching into a conventional adsorbate evolution mechanism(AEM).More importantly,the activated bridging oxygen(Obri)sites can facilitate the deprotonation of*OOH intermediates,leading to an optimized bridging-oxygen-assisted deprotonation AEM pathway.
基金supported by the National Natural Science Foundation of China(No.U20A20250,22322104,and 22171074)the Heilongjiang Provincial Natural Science Foundation of China(No.YQ2021B009)the Basic Research Fund of Heilongjiang University in Heilongjiang Province(No.2021-KYYWF-0031).
文摘Proton exchange membrane water electrolyzer(PEMWE)technology is regarded as one of the most promising methods for green hydrogen generation.The oxygen evolution reaction(OER)at the anode is the primary bottleneck preventing the industrial-scale application of PEMWEs due to its sluggish kinetics,and it presently relies upon electrocatalysts that use scarce,costly Ru and Ir.In addition,most of the Ru-and Ir-based electrocatalysts developed to date need high noble metal loading and present good activity only at low current density for a short period.In this review,we systematically elaborate upon various effective strategies for modulating Ruand Ir-based catalysts to achieve large current density,high stability,and high atom economy,including singleatom designs,heteroatom doping,defect/vacancy creation,alloying,and heterojunction engineering.The structure–performance relationships of OER catalysts synthesized using different strategies are elucidated,along with the importance of substrate materials.We conclude by discussing the remaining challenges and future prospects for OER electrocatalysts in acid.
