The copper-based electrocatalysts feature attractive potentials of converting CO_(2)into multi-carbon(C_(2+))products,while the instability of Cu-O often induces the reduction of Cu^(+)/Cu^(0) catalytic sites at the c...The copper-based electrocatalysts feature attractive potentials of converting CO_(2)into multi-carbon(C_(2+))products,while the instability of Cu-O often induces the reduction of Cu^(+)/Cu^(0) catalytic sites at the cathode and refrains the capability of stable electrolysis especially at high powers.In this work,we developed an Erbium(Er)oxide-modified Cu(Er-O-Cu)catalyst with enhanced covalency of Cu-O and more stable active sites.The f-p-d coupling strengthens the covalency of Cu-O,and the stability of Cu^(+)sites under electroreduction condition is critical for promoting the C-C coupling and improving the C_(2+)product selectivity.As a result,the Er-O-Cu sites exhibited a high Faradaic efficiency of C_(2+)products(FEC_(2+))of 86%at 2200 mA cm^(-2),and a peak partial current density of|j_(C2+)|of 1900 mA cm^(-2),comparable to the best reported values for the CO_(2)-to-C_(2+)electroreduction.The CO_(2)electrolysis by the Er-O-Cu sites was further scaled up to 100 cm^(2)to achieve high-power(~200 W)electrolysis with ethylene production rate of 16 mL min^(-1).展开更多
In recent years,studies focusing on the conversion of renewable lignin-derived oxygenates(LDOs)have emphasized their potential as alternatives to fossil-based products.However,LDOs,existing as complex aromatic mixture...In recent years,studies focusing on the conversion of renewable lignin-derived oxygenates(LDOs)have emphasized their potential as alternatives to fossil-based products.However,LDOs,existing as complex aromatic mixtures with diverse oxygen-containing functional groups,pose a challenge as they cannot be easily separated via distillation for direct utilization.A promising solution to this challenge lies in the efficient removal of oxygen-containing functional groups from LDOs through hydrodeoxygenation(HDO),aiming to yield biomass products with singular components.However,the high dissociation energy of the carbon-oxygen bond,coupled with its similarity to the hydrogenation energy of the benzene ring,creates a competition between deoxygenation and benzene ring hydrogenation.Considering hydrogen consumption and lignin properties,the preference is directed towards generating aromatic hydrocarbons rather than saturated components.Thus,the goal is to selectively remove oxygen-containing functional groups while preserving the benzene ring structure.Studies on LDOs conversion have indicated that the design of active components and optimization of reaction conditions play pivotal roles in achieving selective deoxygenation,but a summary of the correlation between these factors and the reaction mechanism is lacking.This review addresses this gap in knowledge by firstly summarizing the various reaction pathways for HDO of LDOs.It explores the impact of catalyst design strategies,including morphology modulation,elemental doping,and surface modification,on the adsorption-desorption dynamics between reactants and catalysts.Secondly,we delve into the application of advanced techniques such as spectroscopic techniques and computational modeling,aiding in uncovering the true active sites in HDO reactions and understanding the interaction of reactive reactants with catalyst surface-interfaces.Additionally,fundamental insights into selective deoxygenation obtained through these techniques are highlighted.Finally,we outline the challenges that lie ahead in the design of highly active and selective HDO catalysts.These challenges include the development of detection tools for reactive species with high activity at low concentrations,the study of reaction medium-catalyst interactions,and the development of theoretical models that more closely approximate real reaction situations.Addressing these challenges will pave the way for the development of efficient and selective HDO catalysts,thus advancing the field of renewable LDOs conversion.展开更多
This study investigates the effects of Fe on the oxygen-evolution reaction(OER)in the presence of Au.Two distinct areas of OER were identified:the first associated with Fe sites at low overpotential(~330 mV),and the s...This study investigates the effects of Fe on the oxygen-evolution reaction(OER)in the presence of Au.Two distinct areas of OER were identified:the first associated with Fe sites at low overpotential(~330 mV),and the second with Au sites at high overpotential(~870 mV).Various factors such as surface Fe concentration,electrochemical method,scan rate,potential range,concentration,method of adding K_(2)Fe O_(4),nature of Fe,and temperature were varied to observe diverse behaviors during OER for Fe O_(x)H_(y)/Au.Trace amounts of Fe ions had a significant impact on OER,reaching a saturation point where the activity did not increase further.Strong electronic interaction between Fe and Au ions was indicated by X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)analyses.In situ visible spectroscopy confirmed the formation of Fe O_(4)^(2-)during OER.In situ Mossbauer and surfaceenhanced Raman spectroscopy(SERS)analyses suggest the involvement of Fe-based species as intermediates during the rate-determining step of OER.A lattice OER mechanism based on Fe O_(x)H_(y)was proposed for operation at low overpotentials.Density functional theory(DFT)calculations revealed that Fe oxide,Fe-oxide clusters,and Fe doping on the Au foil exhibited different activities and stabilities during OER.The study provides insights into the interplay between Fe and Au in OER,advancing the understanding of OER mechanisms and offering implications for the design of efficient electrocatalytic systems.展开更多
Simultaneous nitrate reduction and sulfide oxidation reactions(NO_(3)RR and SOR)to generate valuable chemicals represent an appealing strategy for green synthesis;however,the sluggish kinetics seriously hinder their a...Simultaneous nitrate reduction and sulfide oxidation reactions(NO_(3)RR and SOR)to generate valuable chemicals represent an appealing strategy for green synthesis;however,the sluggish kinetics seriously hinder their application.Herein,we report that Ni dopants can optimize the electronic structure of MoS_(2),which thus favors the adsorption of reactants/intermediates and reduces the corresponding energy barriers.As a result,the designed catalyst shows a maximal Faradic efficiency of 88.4%and a corresponding yield rate of 66.7μmol·h^(-1)·cm^(-2)for NH3 synthesis,accompanied by a high robustness over 60 h.Besides,it can also trigger the SOR activity with a low potential of 0.105 V vs.reversible hydrogen electrode(RHE)to produce 10 mA·cm^(-2),far smaller than that needed for conventional water oxidation(1.545 V vs.RHE).Accordingly,a coupling system with NO_(3)RR and SOR is constructed for synchronous formation of value-added products on both anode and cathode.This work demonstrates an attractive attempt to construct advanced MoS_(2-)based catalysts towards electrosynthesis.展开更多
Water electrolysis for hydrogen production holds great promise as an energy conversion technology.The electrolysis process contains two necessary electrocatalytic reactions,one is the hydrogen evolution reaction(HER)a...Water electrolysis for hydrogen production holds great promise as an energy conversion technology.The electrolysis process contains two necessary electrocatalytic reactions,one is the hydrogen evolution reaction(HER)at the cathode,and the other is the oxygen evolution reaction(OER)at the anode.In general,the kinetics of OER is much slower than that of HER,dominating the overall of performance electrolysis.As identified,the slow kinetics of catalytic OER is mainly resulted from multiple electron transfer steps,and the catalysts often undergo compositional,structural,and electronic changes during operation,leading to complicated dynamic reaction mechanisms which have not been fully understood.Obviously,this challenge presents formidable obstacles to the development of highly efficient OER electrocatalysts.To address the issue,it is crucial to unravel the origins of intrinsic OER activity and stability and elucidate the catalytic mechanisms across diverse catalyst materials.In this context,in-situ/operando characterization techniques would play a pivotal role in understanding the catalytic reaction mechanisms by enabling real-time monitoring of catalyst structures under operational conditions.These techniques can facilitate the identification of active sites for OER and provide essential insights into the types and quantities of key reaction intermediates.This comprehensive review explores various catalyst design and synthesis strategies aimed at enhancing the intrinsic OER activity and stability of catalysts and examines the application of advanced in-situ/operando techniques for probing catalyst mechanisms during the OER process.Furthermore,the imperative need for developing innovative in-situ/operando techniques,theoretical artificial intelligence and machine learning and conducting theoretical research to better understand catalyst structural evolution under conditions closely resembling practical OER working states is also deeply discussed.Those efforts should be able to lay the foundation for the improved fabrication of practical OER catalysts.展开更多
基金the National Key Research and Development Program of China(2024YFB4106400,2024YFB4106401)the National Natural Science Foundation of China(22025502,U23A20552)。
文摘The copper-based electrocatalysts feature attractive potentials of converting CO_(2)into multi-carbon(C_(2+))products,while the instability of Cu-O often induces the reduction of Cu^(+)/Cu^(0) catalytic sites at the cathode and refrains the capability of stable electrolysis especially at high powers.In this work,we developed an Erbium(Er)oxide-modified Cu(Er-O-Cu)catalyst with enhanced covalency of Cu-O and more stable active sites.The f-p-d coupling strengthens the covalency of Cu-O,and the stability of Cu^(+)sites under electroreduction condition is critical for promoting the C-C coupling and improving the C_(2+)product selectivity.As a result,the Er-O-Cu sites exhibited a high Faradaic efficiency of C_(2+)products(FEC_(2+))of 86%at 2200 mA cm^(-2),and a peak partial current density of|j_(C2+)|of 1900 mA cm^(-2),comparable to the best reported values for the CO_(2)-to-C_(2+)electroreduction.The CO_(2)electrolysis by the Er-O-Cu sites was further scaled up to 100 cm^(2)to achieve high-power(~200 W)electrolysis with ethylene production rate of 16 mL min^(-1).
基金supported by the National Natural Science Foundation of China,Pilot Group Program of the Research Fund for International Senior Scientists(22250710676)National Natural Science Foundation of China(22078064,22378062,22304028)+1 种基金Natural Science Foundation of Fujian Province(2021J02009)Tianjin University-Fuzhou University Independent Innovation Fund Cooperation Project(TF2023-1,TF2023-8).
文摘In recent years,studies focusing on the conversion of renewable lignin-derived oxygenates(LDOs)have emphasized their potential as alternatives to fossil-based products.However,LDOs,existing as complex aromatic mixtures with diverse oxygen-containing functional groups,pose a challenge as they cannot be easily separated via distillation for direct utilization.A promising solution to this challenge lies in the efficient removal of oxygen-containing functional groups from LDOs through hydrodeoxygenation(HDO),aiming to yield biomass products with singular components.However,the high dissociation energy of the carbon-oxygen bond,coupled with its similarity to the hydrogenation energy of the benzene ring,creates a competition between deoxygenation and benzene ring hydrogenation.Considering hydrogen consumption and lignin properties,the preference is directed towards generating aromatic hydrocarbons rather than saturated components.Thus,the goal is to selectively remove oxygen-containing functional groups while preserving the benzene ring structure.Studies on LDOs conversion have indicated that the design of active components and optimization of reaction conditions play pivotal roles in achieving selective deoxygenation,but a summary of the correlation between these factors and the reaction mechanism is lacking.This review addresses this gap in knowledge by firstly summarizing the various reaction pathways for HDO of LDOs.It explores the impact of catalyst design strategies,including morphology modulation,elemental doping,and surface modification,on the adsorption-desorption dynamics between reactants and catalysts.Secondly,we delve into the application of advanced techniques such as spectroscopic techniques and computational modeling,aiding in uncovering the true active sites in HDO reactions and understanding the interaction of reactive reactants with catalyst surface-interfaces.Additionally,fundamental insights into selective deoxygenation obtained through these techniques are highlighted.Finally,we outline the challenges that lie ahead in the design of highly active and selective HDO catalysts.These challenges include the development of detection tools for reactive species with high activity at low concentrations,the study of reaction medium-catalyst interactions,and the development of theoretical models that more closely approximate real reaction situations.Addressing these challenges will pave the way for the development of efficient and selective HDO catalysts,thus advancing the field of renewable LDOs conversion.
基金the National Elite Foundationthe Institute for Advanced Studies in Basic Sciences for their financial supportfinancially supported by the National Natural Science Foundation of China(22173026,22350410386,22375200,U22A202175,21961142006)。
文摘This study investigates the effects of Fe on the oxygen-evolution reaction(OER)in the presence of Au.Two distinct areas of OER were identified:the first associated with Fe sites at low overpotential(~330 mV),and the second with Au sites at high overpotential(~870 mV).Various factors such as surface Fe concentration,electrochemical method,scan rate,potential range,concentration,method of adding K_(2)Fe O_(4),nature of Fe,and temperature were varied to observe diverse behaviors during OER for Fe O_(x)H_(y)/Au.Trace amounts of Fe ions had a significant impact on OER,reaching a saturation point where the activity did not increase further.Strong electronic interaction between Fe and Au ions was indicated by X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)analyses.In situ visible spectroscopy confirmed the formation of Fe O_(4)^(2-)during OER.In situ Mossbauer and surfaceenhanced Raman spectroscopy(SERS)analyses suggest the involvement of Fe-based species as intermediates during the rate-determining step of OER.A lattice OER mechanism based on Fe O_(x)H_(y)was proposed for operation at low overpotentials.Density functional theory(DFT)calculations revealed that Fe oxide,Fe-oxide clusters,and Fe doping on the Au foil exhibited different activities and stabilities during OER.The study provides insights into the interplay between Fe and Au in OER,advancing the understanding of OER mechanisms and offering implications for the design of efficient electrocatalytic systems.
基金supported by the Guangxi Natural Science Fund for Distinguished Young Scholars(No.2024GXNSFFA010008)the National Natural Science Foundation of China(Nos.22469002 and 22304028)Natural Science Foundation of Jilin Province of China(No.20240101098JC).
文摘Simultaneous nitrate reduction and sulfide oxidation reactions(NO_(3)RR and SOR)to generate valuable chemicals represent an appealing strategy for green synthesis;however,the sluggish kinetics seriously hinder their application.Herein,we report that Ni dopants can optimize the electronic structure of MoS_(2),which thus favors the adsorption of reactants/intermediates and reduces the corresponding energy barriers.As a result,the designed catalyst shows a maximal Faradic efficiency of 88.4%and a corresponding yield rate of 66.7μmol·h^(-1)·cm^(-2)for NH3 synthesis,accompanied by a high robustness over 60 h.Besides,it can also trigger the SOR activity with a low potential of 0.105 V vs.reversible hydrogen electrode(RHE)to produce 10 mA·cm^(-2),far smaller than that needed for conventional water oxidation(1.545 V vs.RHE).Accordingly,a coupling system with NO_(3)RR and SOR is constructed for synchronous formation of value-added products on both anode and cathode.This work demonstrates an attractive attempt to construct advanced MoS_(2-)based catalysts towards electrosynthesis.
基金supported by the National Key R&D Project(2022YFB4004100)National Natural Science Foundation of China,Pilot Group Program of the Research Fund for International Senior Scientists(22250710676)+1 种基金National Natural Science Foundation of China(22221005,22078064,22304028)Natural Science Foundation of Fujian Province(2021J02009).
文摘Water electrolysis for hydrogen production holds great promise as an energy conversion technology.The electrolysis process contains two necessary electrocatalytic reactions,one is the hydrogen evolution reaction(HER)at the cathode,and the other is the oxygen evolution reaction(OER)at the anode.In general,the kinetics of OER is much slower than that of HER,dominating the overall of performance electrolysis.As identified,the slow kinetics of catalytic OER is mainly resulted from multiple electron transfer steps,and the catalysts often undergo compositional,structural,and electronic changes during operation,leading to complicated dynamic reaction mechanisms which have not been fully understood.Obviously,this challenge presents formidable obstacles to the development of highly efficient OER electrocatalysts.To address the issue,it is crucial to unravel the origins of intrinsic OER activity and stability and elucidate the catalytic mechanisms across diverse catalyst materials.In this context,in-situ/operando characterization techniques would play a pivotal role in understanding the catalytic reaction mechanisms by enabling real-time monitoring of catalyst structures under operational conditions.These techniques can facilitate the identification of active sites for OER and provide essential insights into the types and quantities of key reaction intermediates.This comprehensive review explores various catalyst design and synthesis strategies aimed at enhancing the intrinsic OER activity and stability of catalysts and examines the application of advanced in-situ/operando techniques for probing catalyst mechanisms during the OER process.Furthermore,the imperative need for developing innovative in-situ/operando techniques,theoretical artificial intelligence and machine learning and conducting theoretical research to better understand catalyst structural evolution under conditions closely resembling practical OER working states is also deeply discussed.Those efforts should be able to lay the foundation for the improved fabrication of practical OER catalysts.
