“Three-in-one”cathode,achieved via B-site heavy-doping of transition elements(typically Co,Fe)into proton-conductive perovskite,holds promise for enhancing the performance of proton-conducting solid oxide fuel cell(...“Three-in-one”cathode,achieved via B-site heavy-doping of transition elements(typically Co,Fe)into proton-conductive perovskite,holds promise for enhancing the performance of proton-conducting solid oxide fuel cell(H-SOFC)operated below 650℃for electricity generation.However,its electrochemical behavior above 650℃,essential for improving the efficiency of H-SOFC for fuel conversion,remains insufficiently explored.It is still challenging to propose guidance for the design of“threein-one”cathode toward optimal H-SOFC performance below and above 650℃,with the prerequisite of gaining a comprehensive understanding of the roles of Co and Fe in determining the H-SOFC performance.This work is to address this challenge.Through theoretical/experimental studies,Co is identified to play a role in improving the oxygen reduction reaction(ORR)activity while Fe plays a role in facilitating the cathode/electrolyte interfacial proton conduction.Therefore,if the operating temperature is above 650℃,lowering the Co/Fe ratio in“three-in-one”cathode becomes crucial since the limiting factor shifts from ORR activity to proton conduction.Implementing this strategy,the SOFC using BaCo_(0.15)-Fe_(0.55)Zr_(0.1)Y_(0.1)Yb_(0.1)O_(3−δ)cathode achieves peak power densities of 1.67Wcm^(−2)under H-SOFC mode at 700℃and 2.32Wcm^(−2)under dual ion-conducting SOFC mode at 750℃,which are the highest reported values so far.展开更多
Tantalum nitride is widely considered as a promising photoanode material for its suitable band structure as well as the high theoretical conversion efficiency in solar water splitting.However,it is limited to ineffici...Tantalum nitride is widely considered as a promising photoanode material for its suitable band structure as well as the high theoretical conversion efficiency in solar water splitting.However,it is limited to inefficient photoinduced electron–hole pair separation and interfacial dynamics in the photoelectrochemical oxygen evolution reaction.Herein,multiple layers including Ti_(x)Si_(y) and NiFeCoO_(x) were fabricated based on band engineering to regulate tandem electric states for efficient transfer of energy carriers.Besides,photothermal local surface plasmon resonance was introduced to accelerate the kinetics of photoelectrochemical reactions at the interface when the special Ag nanoparticles were loaded to extend the absorbance to near infrared light.Consequently,a recordable photocurrent density of 12.73 mA cm^(-2) has been achieved at 1.23 V versus RHE,approaching a theoretical limit of the tantalum nitride photoanode with full-spectrum solar utilization.Meanwhile,compared to the applied bias photon-to-current efficiency of 1.36%without photothermal factor,a high applied bias photonto-current efficiency of 2.27%could be raised by applying local surface plasmon resonance to photoelectrochemical oxygen evolution reaction.The efficient design could maximize the use of solar light via the classification of spectrum and,therefore,may spark more innovative ideas for the future design and development of the next-generation photoelectrode.展开更多
Electrochemical reduction of CO_(2)to formate is economically attractive but improving the reaction selectivity and activity remains challenging.Herein,we introduce boron(B)atoms to modify the local electronic structu...Electrochemical reduction of CO_(2)to formate is economically attractive but improving the reaction selectivity and activity remains challenging.Herein,we introduce boron(B)atoms to modify the local electronic structure of bismuth with positive valence sites for boosting conversion of CO_(2)into formate with high activity and selectivity in a wide potential window.By combining experimental and computational investigations,our study indicates that B dopant differentiates the proton participations of rate-determining steps in CO_(2)reduction and in the competing hydrogen evolution.By comparing the experimental observations with the density functional theory,the dominant mechanistic pathway of B promoted formate generation and the B concentration modulated effects on the catalytic property of Bi are unravelled.This comprehensive study offers deep mechanistic insights into the reaction pathway at an atomic and molecular level and provides an effective strategy for the rational design of highly active and selective electrocatalysts for efficient CO_(2)conversion.展开更多
基金supported by the Natural Sciences and Engineering Research Council(NSERC)of Canada,Discovery Grant(GRPIN-2016-05494)Strategic Research Projects of Alberta Innovates Technology Futures(#G2016000655)funding from the Canada First Research Excellence Fund(CFREF-2015-00001).
文摘“Three-in-one”cathode,achieved via B-site heavy-doping of transition elements(typically Co,Fe)into proton-conductive perovskite,holds promise for enhancing the performance of proton-conducting solid oxide fuel cell(H-SOFC)operated below 650℃for electricity generation.However,its electrochemical behavior above 650℃,essential for improving the efficiency of H-SOFC for fuel conversion,remains insufficiently explored.It is still challenging to propose guidance for the design of“threein-one”cathode toward optimal H-SOFC performance below and above 650℃,with the prerequisite of gaining a comprehensive understanding of the roles of Co and Fe in determining the H-SOFC performance.This work is to address this challenge.Through theoretical/experimental studies,Co is identified to play a role in improving the oxygen reduction reaction(ORR)activity while Fe plays a role in facilitating the cathode/electrolyte interfacial proton conduction.Therefore,if the operating temperature is above 650℃,lowering the Co/Fe ratio in“three-in-one”cathode becomes crucial since the limiting factor shifts from ORR activity to proton conduction.Implementing this strategy,the SOFC using BaCo_(0.15)-Fe_(0.55)Zr_(0.1)Y_(0.1)Yb_(0.1)O_(3−δ)cathode achieves peak power densities of 1.67Wcm^(−2)under H-SOFC mode at 700℃and 2.32Wcm^(−2)under dual ion-conducting SOFC mode at 750℃,which are the highest reported values so far.
基金financially supported by the Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ24E060001the National Key Research and Development Project(2023YFC3710800)+2 种基金the National Natural Science Foundation of China under Grant No.52341602supported by funding from the Canada First Research Excellence Fund(CFRER-2015-00001)the University of Alberta’s Future Energy Systems research initiative(FES-T02-P03)。
文摘Tantalum nitride is widely considered as a promising photoanode material for its suitable band structure as well as the high theoretical conversion efficiency in solar water splitting.However,it is limited to inefficient photoinduced electron–hole pair separation and interfacial dynamics in the photoelectrochemical oxygen evolution reaction.Herein,multiple layers including Ti_(x)Si_(y) and NiFeCoO_(x) were fabricated based on band engineering to regulate tandem electric states for efficient transfer of energy carriers.Besides,photothermal local surface plasmon resonance was introduced to accelerate the kinetics of photoelectrochemical reactions at the interface when the special Ag nanoparticles were loaded to extend the absorbance to near infrared light.Consequently,a recordable photocurrent density of 12.73 mA cm^(-2) has been achieved at 1.23 V versus RHE,approaching a theoretical limit of the tantalum nitride photoanode with full-spectrum solar utilization.Meanwhile,compared to the applied bias photon-to-current efficiency of 1.36%without photothermal factor,a high applied bias photonto-current efficiency of 2.27%could be raised by applying local surface plasmon resonance to photoelectrochemical oxygen evolution reaction.The efficient design could maximize the use of solar light via the classification of spectrum and,therefore,may spark more innovative ideas for the future design and development of the next-generation photoelectrode.
基金This work was supported by the Shenzhen Science and Technology Program(KQTD20190929173914967)。
文摘Electrochemical reduction of CO_(2)to formate is economically attractive but improving the reaction selectivity and activity remains challenging.Herein,we introduce boron(B)atoms to modify the local electronic structure of bismuth with positive valence sites for boosting conversion of CO_(2)into formate with high activity and selectivity in a wide potential window.By combining experimental and computational investigations,our study indicates that B dopant differentiates the proton participations of rate-determining steps in CO_(2)reduction and in the competing hydrogen evolution.By comparing the experimental observations with the density functional theory,the dominant mechanistic pathway of B promoted formate generation and the B concentration modulated effects on the catalytic property of Bi are unravelled.This comprehensive study offers deep mechanistic insights into the reaction pathway at an atomic and molecular level and provides an effective strategy for the rational design of highly active and selective electrocatalysts for efficient CO_(2)conversion.
