Highly stable and efficient non-noble-metal electrocatalysts are strongly desired for the oxygen evolution reaction (OER) in alkaline media.In this study,we report the use of 4,4’-biphenyl dicarboxylic acid as an org...Highly stable and efficient non-noble-metal electrocatalysts are strongly desired for the oxygen evolution reaction (OER) in alkaline media.In this study,we report the use of 4,4’-biphenyl dicarboxylic acid as an organic ligand to in situ develop an Ni-MOF nanosheet array on nickel foam (Ni-MOF/NF) as an OER catalyst.In 1 M KOH,such 3D Ni-MOF/NF drives a current density of 20 mA cm^(−2) at a low overpotential of 350 mV.Moreover,it exhibits strong long-term electrochemical stability for at least 24 h and achieves a high turnover frequency of 0.24 mol O_(2) per s at an overpotential of 400 mV.展开更多
The development of efficient hydrogen evolution reaction(HER)catalysts is of great importance for electrolytic hydrogen production in alkaline media.In this communication,we report the development of an ultrafine PtNi...The development of efficient hydrogen evolution reaction(HER)catalysts is of great importance for electrolytic hydrogen production in alkaline media.In this communication,we report the development of an ultrafine PtNi nanoparticle-decorated Ni nanosheet array with ultralow Pt loading(7.7 wt%)as a superior electrocatalyst for the alkaline HER.Such a nanoarray drives a geometrical current density of 10 mA cm^(−2)at an overpotential as low as 38 mV in 0.1 M KOH,outperforming commercial 20 wt%Pt/C and all reported HER electrocatalysts.Remarkably,it also shows outstanding long-term electrochemical durability with a faradaic efficiency close to 100%.This work provides us with an attractive ultralow-Ptcontent catalyst material in water-splitting devices toward high-performance and durable electrochemical production of hydrogen fuels.展开更多
Developing low-cost and highly efficient oxygen electrocatalysts for both the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)has become one important issue recently due to the sluggish kinetics of the...Developing low-cost and highly efficient oxygen electrocatalysts for both the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)has become one important issue recently due to the sluggish kinetics of these two reactions,which require high overpotentials and thus high energy input.Perovskite oxides have emerged as a new class of highly efficient non-precious metal catalysts for oxygen electrocatalysis in alkaline media.In this work,an IrO_(2)-incorporated La_(0.8)Sr_(0.2)MnO_(3) composite has been developed as a novel bifunctional oxygen electrocatalyst using a polymer-assisted approach with a subsequent wet impregnation-calcination method.Due to the synergistic effect between the high ORR activity of La_(0.8)Sr_(0.2)MnO_(3) and the good OER activity of IrO_(2) as well as the improved electrochemically active surface area,the electrocatalytic activities of the composite for both the OER and ORR have been improved,compared with those of the pristine La_(0.8)Sr_(0.2)MnO_(3)(ΔE=1.043 V),resulting in its enhanced bifunctionality(ΔE=0.652 V)as an oxygen catalyst in alkaline solution,which is also superior to the reported stateof-the-art electrocatalysts.The stability test shows that after 1000 cycles of cyclic voltammetry(CV),there is only 15 mV positive shift for achieving a current density of 10 mA cm−2 in the OER and 17 mV negative shift to reach a current density of−1 mA cm^(−2) in the ORR,which indicates the good stability of the electrocatalyst(5 wt%IrO_(2) incorporated La_(0.8)Sr_(0.2)MnO_(3))in alkaline solution.Our study not only reports a new composite material as a bifunctional oxygen electrocatalyst,but also opens a new avenue to develop novel perovskite oxide-based electrocatalysts with enhanced bifunctional electrocatalytic activities.展开更多
The electrocatalytic hydrogen evolution reaction(HER)has been explored using mono-and bimetallic Pt-Ru nanoparticles(NPs)deposited onto nitrogen-doped reduced graphene oxide(NH_(2)-rGO)in acidic media.In this contribu...The electrocatalytic hydrogen evolution reaction(HER)has been explored using mono-and bimetallic Pt-Ru nanoparticles(NPs)deposited onto nitrogen-doped reduced graphene oxide(NH_(2)-rGO)in acidic media.In this contribution,monometallic and bimetallic nanoparticles with three different Pt/Ru ratios(1/5,1/1,and 5/1)have been used,yielding five different materials denoted as Pt_(x)Ru_(y)@NH_(2)-rGO(x=0,y=1;x=1,y=0;x=1,y=5;x=1,y=1;x=5,y=1).The materials were characterized using a variety of state-of-the-art techniques,including high-angle annular dark field scanning transmission electron microscopy(HAADF-STEM),energy dispersive X-Ray spectroscopy(EDX)and X-Ray absorption spectroscopy(XAS),enabling the investigation of differences in morphology,coordination environment and oxidation state as a function of the metal composition of the graphene-supported NPs.The materials exhibited HER activity and demonstrated competitive overpotentials close to the thermodynamic limit.The initial catalytic activity of the as-synthesized materials enhances as the Pt/Ru ratio increases.Chronopotentiometry cathodic experiments showed that under reductive conditions the electrocatalytic performance is drastically impacted.Ru-rich materials were activated,whereas Pt-rich materials showed poor stability.Upon applying a reducing potential for 58 h,Pt_(1)Ru_(5)@NH_(2)-rGO reached the best catalytic activity with outstanding overpotentials of η_(0)=0 mV and η_(10)=3 mV and no signs of deactivation even after 12 additional hours of electrolysis.According to DFT calculations,all nanoparticles present surface sites whose hydrogen adsorption energy is optimal for HER.In agreement with the experimental data,the Pt1Ru5 model shows the highest number of highly active sites,especially those involving Ru centres close to the Pt-Ru interface.Combining in-depth characterization and computational modelling,this work reveals that the synergy between the two metals,structural features,and their affinity for the support are responsible for the observed differences in catalytic activities and stabilities.展开更多
It is highly attractive to develop high-performance non-noble-metal electrocatalysts for water oxidation in alkaline media.In this communication,we report the hydrothermal growth of a Co-MOF nanosheet array on Ni foam...It is highly attractive to develop high-performance non-noble-metal electrocatalysts for water oxidation in alkaline media.In this communication,we report the hydrothermal growth of a Co-MOF nanosheet array on Ni foam(Co-MOF/NF)as a 3D oxygen evolution reaction catalyst in alkaline media.The Co-MOF/NF demonstrates superior activity and needs an overpotential of only 311 mV to drive a geometrical catalytic current density of 50 mA cm^(-2)in 1.0 M KOH.展开更多
基金supported by the National Natural Science Foundation of China(no.22072015)the Shanghai Scientific and Technological Innovation Project(no.18JC1410604).
文摘Highly stable and efficient non-noble-metal electrocatalysts are strongly desired for the oxygen evolution reaction (OER) in alkaline media.In this study,we report the use of 4,4’-biphenyl dicarboxylic acid as an organic ligand to in situ develop an Ni-MOF nanosheet array on nickel foam (Ni-MOF/NF) as an OER catalyst.In 1 M KOH,such 3D Ni-MOF/NF drives a current density of 20 mA cm^(−2) at a low overpotential of 350 mV.Moreover,it exhibits strong long-term electrochemical stability for at least 24 h and achieves a high turnover frequency of 0.24 mol O_(2) per s at an overpotential of 400 mV.
文摘The development of efficient hydrogen evolution reaction(HER)catalysts is of great importance for electrolytic hydrogen production in alkaline media.In this communication,we report the development of an ultrafine PtNi nanoparticle-decorated Ni nanosheet array with ultralow Pt loading(7.7 wt%)as a superior electrocatalyst for the alkaline HER.Such a nanoarray drives a geometrical current density of 10 mA cm^(−2)at an overpotential as low as 38 mV in 0.1 M KOH,outperforming commercial 20 wt%Pt/C and all reported HER electrocatalysts.Remarkably,it also shows outstanding long-term electrochemical durability with a faradaic efficiency close to 100%.This work provides us with an attractive ultralow-Ptcontent catalyst material in water-splitting devices toward high-performance and durable electrochemical production of hydrogen fuels.
基金support from USDA National Institute of Food and Agriculture,HSI Collaboration:Integrating Food Science/Engineering and Education Network(IFSEEN,award number:2015-38422-24059)supported by the Idaho National Laboratory Directed Research and Development Program under DOE Idaho Operations Office Contract DE-AC07-05ID14517.
文摘Developing low-cost and highly efficient oxygen electrocatalysts for both the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)has become one important issue recently due to the sluggish kinetics of these two reactions,which require high overpotentials and thus high energy input.Perovskite oxides have emerged as a new class of highly efficient non-precious metal catalysts for oxygen electrocatalysis in alkaline media.In this work,an IrO_(2)-incorporated La_(0.8)Sr_(0.2)MnO_(3) composite has been developed as a novel bifunctional oxygen electrocatalyst using a polymer-assisted approach with a subsequent wet impregnation-calcination method.Due to the synergistic effect between the high ORR activity of La_(0.8)Sr_(0.2)MnO_(3) and the good OER activity of IrO_(2) as well as the improved electrochemically active surface area,the electrocatalytic activities of the composite for both the OER and ORR have been improved,compared with those of the pristine La_(0.8)Sr_(0.2)MnO_(3)(ΔE=1.043 V),resulting in its enhanced bifunctionality(ΔE=0.652 V)as an oxygen catalyst in alkaline solution,which is also superior to the reported stateof-the-art electrocatalysts.The stability test shows that after 1000 cycles of cyclic voltammetry(CV),there is only 15 mV positive shift for achieving a current density of 10 mA cm−2 in the OER and 17 mV negative shift to reach a current density of−1 mA cm^(−2) in the ORR,which indicates the good stability of the electrocatalyst(5 wt%IrO_(2) incorporated La_(0.8)Sr_(0.2)MnO_(3))in alkaline solution.Our study not only reports a new composite material as a bifunctional oxygen electrocatalyst,but also opens a new avenue to develop novel perovskite oxide-based electrocatalysts with enhanced bifunctional electrocatalytic activities.
基金MINECO/FEDER(PID2019-104171RB-I00)MICINN(PID2023-146787OB-I00)for financial support+4 种基金L.M.M.P.also acknowledges the Junta de Andalucía(ProyExcel_00706)for financial supportas well as Grants PID2021-126080OA-I00,TED2021-132087A-I00 and CNS2023-145078funded by MICIU/AEI/10.13039/501100011033 and by“ERDF/EU”and“European Union NextGenerationEU/PRTR.L.R.-S.and X.S.-M.acknowledge financial support from MICINN(PID2023-151738NB-I00)X-Ray Absoprtion experiments were performed at CLAESS beamline(experiment 2020084432)with the collaboration of ALBA staffH.H.acknowledge the China Scholarships Council(No.201908440337)for her PhD grant.
文摘The electrocatalytic hydrogen evolution reaction(HER)has been explored using mono-and bimetallic Pt-Ru nanoparticles(NPs)deposited onto nitrogen-doped reduced graphene oxide(NH_(2)-rGO)in acidic media.In this contribution,monometallic and bimetallic nanoparticles with three different Pt/Ru ratios(1/5,1/1,and 5/1)have been used,yielding five different materials denoted as Pt_(x)Ru_(y)@NH_(2)-rGO(x=0,y=1;x=1,y=0;x=1,y=5;x=1,y=1;x=5,y=1).The materials were characterized using a variety of state-of-the-art techniques,including high-angle annular dark field scanning transmission electron microscopy(HAADF-STEM),energy dispersive X-Ray spectroscopy(EDX)and X-Ray absorption spectroscopy(XAS),enabling the investigation of differences in morphology,coordination environment and oxidation state as a function of the metal composition of the graphene-supported NPs.The materials exhibited HER activity and demonstrated competitive overpotentials close to the thermodynamic limit.The initial catalytic activity of the as-synthesized materials enhances as the Pt/Ru ratio increases.Chronopotentiometry cathodic experiments showed that under reductive conditions the electrocatalytic performance is drastically impacted.Ru-rich materials were activated,whereas Pt-rich materials showed poor stability.Upon applying a reducing potential for 58 h,Pt_(1)Ru_(5)@NH_(2)-rGO reached the best catalytic activity with outstanding overpotentials of η_(0)=0 mV and η_(10)=3 mV and no signs of deactivation even after 12 additional hours of electrolysis.According to DFT calculations,all nanoparticles present surface sites whose hydrogen adsorption energy is optimal for HER.In agreement with the experimental data,the Pt1Ru5 model shows the highest number of highly active sites,especially those involving Ru centres close to the Pt-Ru interface.Combining in-depth characterization and computational modelling,this work reveals that the synergy between the two metals,structural features,and their affinity for the support are responsible for the observed differences in catalytic activities and stabilities.
基金supported by the National Natural Science Foundation of China(No.21775089,21375076)the Key Research and Development Program of Shandong Province(2015GSF121031)the Natural Science Foundation Projects of Shandong Province(No.ZR2017JL010,ZR2017QB008,ZR2017LEE006).
文摘It is highly attractive to develop high-performance non-noble-metal electrocatalysts for water oxidation in alkaline media.In this communication,we report the hydrothermal growth of a Co-MOF nanosheet array on Ni foam(Co-MOF/NF)as a 3D oxygen evolution reaction catalyst in alkaline media.The Co-MOF/NF demonstrates superior activity and needs an overpotential of only 311 mV to drive a geometrical catalytic current density of 50 mA cm^(-2)in 1.0 M KOH.
