Electrochemical reduction of Bi-based metal oxides is regarded as an effective strategy to rationally design advanced electrocatalysts for electrochemical CO_(2)reduction reaction(CO_(2)RR).Realizing high selectivity ...Electrochemical reduction of Bi-based metal oxides is regarded as an effective strategy to rationally design advanced electrocatalysts for electrochemical CO_(2)reduction reaction(CO_(2)RR).Realizing high selectivity at high current density is important for formate production,but remains challenging.Herein,the BiIn hybrid electrocatalyst,deriving from the Bi2O3/In2O3heterojunction(MOD-Biln),shows excellent catalytic performance for CO_(2)RR.The Faradaic efficiency of formate(FEHCOO-) can be realized over 90% at a wide potential window from-0.4 to-1.4 V vs.RHE,while the partial current density of formate(jHCOO-) reaches about 136.7 mA cm^(-2)at-1.4 V in flow cell without IR-compensation.In additio n,the MOD-Biln exhibits superior stability with high selectivity of formate at 100 mA cm^(-2).Systematic characterizations prove the optimized catalytic sites and interface charge transfer of MOD-Biln,while theoretical calculation confirms that the hybrid structure with dual Bi/In metal sites contribute to the optimal free energy of*H and*OCHO intermediates on MOD-Biln surface,thus accelerating the formation and desorption step of*HCOOH to final formate production.Our work provides a facile and useful strategy to develop highly-active and stable electrocatalysts for CO_(2)RR.展开更多
Electrocatalytic overall water splitting(OWS),a pivotal approach in addressing the global energy crisis,aims to produce hydrogen and oxygen.However,most of the catalysts in powder form are adhesively bounding to the e...Electrocatalytic overall water splitting(OWS),a pivotal approach in addressing the global energy crisis,aims to produce hydrogen and oxygen.However,most of the catalysts in powder form are adhesively bounding to the electrodes,resulting in catalyst detachment by bubble generation and other uncertain interference,and eventually reducing the OWS performance.To surmount this challenge,we synthesized a hybrid material of Co_(3)S_(4)-pyrolysis lotus fiber(labeled as Co_(3)S_(4)-p LF)textile by hydrothermal and hightemperature pyrolysis processes for electrocatalytic OWS.Owing to the natural LF textile exposing the uniformly distributed functional groups(AOH,ANH_(2),etc.)to anchor Co_(3)S_(4)nanoparticles with hierarchical porous structure and outstanding hydrophily,the hybrid Co_(3)S_(4)-p LF catalyst shows low overpotentials at 10 m A cm^(-2)(η_(10,HER)=100 m Vη_(10,OER)=240 mV)alongside prolonged operational stability during electrocatalytic reactions.Theoretical calculations reveal that the electron transfer from p LF to Co_(3)S_(4)in the hybrid Co_(3)S_(4)-p LF is beneficial to the electrocatalytic process.This work will shed light on the development of nature-inspired carbon-based materials in hybrid electrocatalysts for OWS.展开更多
Hydrogen evolution reaction (HER) is an essential step in converting renewable energy to clean hydrogen fuel. Exploring highly efficient, stable and cost-effective electrocatalysts is of crucial significance for susta...Hydrogen evolution reaction (HER) is an essential step in converting renewable energy to clean hydrogen fuel. Exploring highly efficient, stable and cost-effective electrocatalysts is of crucial significance for sustainable HER. Here, we report the design of a coupled ruthenium/cobalt oxide (Ru/CoO) hybrid electrocatalyst for alkaline HER. In this hybrid metal/oxide system, the complicated alkaline HER pathways are overall facilitated;oxygen (O)-vacancy-abundant oxide enhances water splitting and Ru promotes successive hydrogen intermediates to generate hydrogen. The resulting Ru/CoO hybrid electrocatalyst exhibits significantly promoted catalytic activity compared with benchmark Ru catalyst, displaying an overpotential of 55 mV to generate a HER current density of 10 mA cm^-2, comparable with the state-of-the-art Pt/C catalyst and the most efficient alkaline HER electrocatalysts. Furthermore, the strong interaction of Ru nanoparticles with oxide support and the in-situ growth of oxide support on conductive substrate guarantee the long-term stability of as-fabricated Ru/CoO hybrid electrocatalyst. This newly designed hybrid catalyst with abundant metal/oxide interfaces may pave a new pathway for exploring efficient and stable HER electrocatalysts.展开更多
Hydrogen is widely regarded as a crucial energy carrier for achieving carbon neutrality and a sustainable future.Direct seawater electrolysis using renewable energy presents a promising approach for large-scale hydrog...Hydrogen is widely regarded as a crucial energy carrier for achieving carbon neutrality and a sustainable future.Direct seawater electrolysis using renewable energy presents a promising approach for large-scale hydrogen production.Reactions of this nature at high current density and Faradaic efficiency are hampered by two challenges.展开更多
Developing transition metal-based electrocatalysts with rich active sites for water electrolysis plays important roles in renewable energy fields. So far, some strategies including designing nanostructures, incorporat...Developing transition metal-based electrocatalysts with rich active sites for water electrolysis plays important roles in renewable energy fields. So far, some strategies including designing nanostructures, incorporating conductive support or foreign elements have been adopted to develop efficient electrocat- alysts. Herein, we summarize recent progresses and propose in-situ electrochemical activation as a new pretreating technique for enhanced catalytic performances. The activation techniques mainly comprise facile electrochemical processes such as anodic oxidation, cathodic reduction, etching, lithium-assisted tuning and counter electrode electro-dissolution. During these electrochemicaI treatments, the catalyst surfaces are modified from bulk phase, which can tune local electronic structures, create more active spe- cies. enlarge surface area and thus improve the catalytic performances. Meanwhile, this technique can couple the atomic, electronic structures with electrocatalysis mechanisms for water splitting. Compared to traditional chemical treatment, the in-situ electrochemical activation techniques have superior advantages such as facile operation, mild environment, variable control, high efficiency and flex- ibility. This review may provide guidance for improving water electrolysis efficiencies and hold promis- ing for application in many other energy-conversion fields such as supercapacitors, fuel cells and batteries.展开更多
Bimetallic Cu-In hybrid electrocatalysts are promising noble metal-free catalysts for selective electrochemical CO_(2) reduction reaction(ECO_(2) RR).Most reports show Cu-In catalysts are selective towards CO evolutio...Bimetallic Cu-In hybrid electrocatalysts are promising noble metal-free catalysts for selective electrochemical CO_(2) reduction reaction(ECO_(2) RR).Most reports show Cu-In catalysts are selective towards CO evolutio n.However,few show similarly high selectivity towards formate.Herein we fabricated composition tunable Cu-In hydroxides(Cu_xIn_y-OH) by the hydrothermal method and studied their composition effect on electrochemical CO_(2) reduction in detail. We found that the selectivity of CO_(2) reduction products shifted from CO to formate when the content of In increased in the Cu_xIn_y-OH electrocatalysts.The Cu rich electrocatalyst mostly produced CO,which could achieve a Faradaic efficiency(FE) to 75.8% at-0.59 V vs.RHE(Cu_(76)In_(24)based electrocatalysts).In comparison,the In rich electrocatalysts selectively produced formate,which possessed the FE of formate up to 85% at-1.01 V vs.RHE.Our work systematically illustrates the composition effect on hybrid catalysts,and provides insights into the design of highly selective catalysts for ECO_(2) RR.展开更多
Abstract The polypyrrole（PPy）@NiCo hybrid nanotube arrays have been successfully fabricated as a high performance electrocatalyst for hydrogen evolution reaction （HER） in alkaline solution. The strong electronic i...Abstract The polypyrrole（PPy）@NiCo hybrid nanotube arrays have been successfully fabricated as a high performance electrocatalyst for hydrogen evolution reaction （HER） in alkaline solution. The strong electronic interactions between PPy and NiCo alloy are confirmed by X-ray photoelectron spectroscopy and Raman spectra. Because these interations can remarkably reduce the apparent activation energy （Ea） for HER and enhance the turnover frequency of catalysts, the electrocatalytic performance of PPy@NiCo hybrid nanotube arrays are significantly improved. The electrochemical tests show that the PPy@NiCo hybrid catalysts exhibit a low overpotential of-186 mV at 10.0 mA·cm^-2 and a small tafel slope of 88.6 mV·deg^-1 for HER in the alkaline solution. The PPy@NiCo hybrid nanotubes also exhibit high catalytic activity and high stability for HER.展开更多
Metal-organic frameworks possessing relatively large pores,high surface areas,and unsaturated metal sites are attractive materials for use as electrocatalysts in the reduction of N_(2)to NH_(3).In this work,a MIL-101(...Metal-organic frameworks possessing relatively large pores,high surface areas,and unsaturated metal sites are attractive materials for use as electrocatalysts in the reduction of N_(2)to NH_(3).In this work,a MIL-101(Fe)/MoS_(3)hybrid catalyst,prepared by using a precursor-transformation strategy,is shown to be an effective electrocatalyst for the N_(2)reduction reaction(NRR).Under solvothermal conditions,micro-sized octahedral MIL-101(Fe)precursors are converted into ultra-small nanodots,while amorphous MoS_(3)derived from(NH_(4))_(2)MoS_(4)provides a surface suitable for anchoring the MIL-101(Fe)nanodots.The asprepared composite exhibits excellent electrocatalytic activity and durability for the NRR with a Faraday efficiency of 36.71%and an NH_(3)yield of 25.7μg h^(-1)mg_(cat)^(-1)at-0.1 V vs.RHE in 0.1 M HCl.The results show that the dispersion and adherence of MIL-101(Fe)nanodots on amorphous MoS_(3)improves the exposure of active centers and aids mass transfer,resulting in greatly enhanced catalytic activity and stability.展开更多
Electrochemical nitrogen reduction reaction(NRR)is a sustainable alterna-tive to the Haber-Bosch process for ammonia(NH3)production.However,the significant uphill energy in the multistep NRR pathway is a bottleneck fo...Electrochemical nitrogen reduction reaction(NRR)is a sustainable alterna-tive to the Haber-Bosch process for ammonia(NH3)production.However,the significant uphill energy in the multistep NRR pathway is a bottleneck for favorable serial reactions.To overcome this challenge,we designed a vanadium oxide/nitride(V_(2)O_(3)/VN)hybrid electrocatalyst in which V_(2)O_(3)and VN coex-ist coherently at the heterogeneous interface.Since single-phase V_(2)O_(3)and VN exhibit different surface catalytic kinetics for NRR,the V_(2)O_(3)/VN hybrid elec-trocatalyst can provide alternating reaction pathways,selecting a lower energy pathway for each material in the serial NRR pathway.As a result,the ammo-nia yield of the V_(2)O_(3)/VN hybrid electrocatalyst was 219.6µg h^(-1)cm^(-2),and the Faradaic efficiency was 18.9%,which is much higher than that of single-phase VN,V_(2)O_(3),and VNxOy solid solution catalysts without heterointerfaces.Density functional theory calculations confirmed that the composition of these hybrid electrocatalysts allows NRR to proceed from a multistep reduction reaction to a low-energy reaction pathway through the migration and adsorption of interme-diate species.Therefore,the design of metal oxide/nitride hybrids with coherent heterointerfaces provides a novel strategy for synthesizing highly efficient elec-trochemical catalysts that induce steps favorable for the efficient low-energy progression of NRR.展开更多
Developments of nanostructured transition metal dichalcogenides （TMDs） materials as novel electrocatalyst candidates for oxygen reduction reaction （ORR） is a new strategy to promote the developments of non-preciou...Developments of nanostructured transition metal dichalcogenides （TMDs） materials as novel electrocatalyst candidates for oxygen reduction reaction （ORR） is a new strategy to promote the developments of non-precious metal ORR catalysts. In this work, a three-dimensional （3D） hybrid of rosebud-like MoSe2 nanostructures supported on reduced graphene oxide （rGO） nanosheets was successfully synthesized through a facile hydrothermal strategy. The prepared MoSe2@rGO hybrid nanostructure showed enhanced electrocatalytic activity for the ORR in alkaline medium compared to that of the pure MoSe2, rGO, and their simple physical mixture, which could benefit from the excellent oxygen adsorption ability of the abundantly exposed active edge sites of the ultrathin MoSe2 layers, the conductivity and aggregation-limiting effect of the rGO platform, as well as the unique 3D rosebud-like architecture of the hybrid material. The electrocatalytic activity of the MoSe2@rGO hybrid towards ORR was comparable to that of com- inertial Pt/C catalysts. And the promoted reaction was revealed to involve a nearly four-electron-dominated ORR process by analysis of the obtained Koutecky- Levich plots. The scanning electrochemical microscopy （SECM） technique, with the advantages of investigating of the local catalytic activity of samples with high spatial resolution and simultaneously evaluating activities of different catalysts in a single experiment, was further applied to investigate the local ORR electrocatalytic activity of MoSe2@rGO and compare it with those of other catalyst samples through applying different sample potentials. The excellent stability and methanol tolerance of the 3D nanostructured MoSe2@rGO hybrid against methanol further prove the 3D nanostructured MoSe2@rGO hybrid as a promising ORR electrocatalyst in alkaline solution for potential applications in fuel cells and metal-air batteries.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 22205205)the Zhejiang Provincial Natural Science Foundation of China (Grant Nos.LQ22B030008)the Science Foundation of Zhejiang Sci-Tech University (ZSTU)(Grant Nos. 21062337-Y and 22062312-Y)。
文摘Electrochemical reduction of Bi-based metal oxides is regarded as an effective strategy to rationally design advanced electrocatalysts for electrochemical CO_(2)reduction reaction(CO_(2)RR).Realizing high selectivity at high current density is important for formate production,but remains challenging.Herein,the BiIn hybrid electrocatalyst,deriving from the Bi2O3/In2O3heterojunction(MOD-Biln),shows excellent catalytic performance for CO_(2)RR.The Faradaic efficiency of formate(FEHCOO-) can be realized over 90% at a wide potential window from-0.4 to-1.4 V vs.RHE,while the partial current density of formate(jHCOO-) reaches about 136.7 mA cm^(-2)at-1.4 V in flow cell without IR-compensation.In additio n,the MOD-Biln exhibits superior stability with high selectivity of formate at 100 mA cm^(-2).Systematic characterizations prove the optimized catalytic sites and interface charge transfer of MOD-Biln,while theoretical calculation confirms that the hybrid structure with dual Bi/In metal sites contribute to the optimal free energy of*H and*OCHO intermediates on MOD-Biln surface,thus accelerating the formation and desorption step of*HCOOH to final formate production.Our work provides a facile and useful strategy to develop highly-active and stable electrocatalysts for CO_(2)RR.
基金supported by the Scientific Research Foundation of Hunan Provincial Education Department,China(22B0893)the Scientific Research Foundation of Hunan Provincial Education Department,China(20A060)。
文摘Electrocatalytic overall water splitting(OWS),a pivotal approach in addressing the global energy crisis,aims to produce hydrogen and oxygen.However,most of the catalysts in powder form are adhesively bounding to the electrodes,resulting in catalyst detachment by bubble generation and other uncertain interference,and eventually reducing the OWS performance.To surmount this challenge,we synthesized a hybrid material of Co_(3)S_(4)-pyrolysis lotus fiber(labeled as Co_(3)S_(4)-p LF)textile by hydrothermal and hightemperature pyrolysis processes for electrocatalytic OWS.Owing to the natural LF textile exposing the uniformly distributed functional groups(AOH,ANH_(2),etc.)to anchor Co_(3)S_(4)nanoparticles with hierarchical porous structure and outstanding hydrophily,the hybrid Co_(3)S_(4)-p LF catalyst shows low overpotentials at 10 m A cm^(-2)(η_(10,HER)=100 m Vη_(10,OER)=240 mV)alongside prolonged operational stability during electrocatalytic reactions.Theoretical calculations reveal that the electron transfer from p LF to Co_(3)S_(4)in the hybrid Co_(3)S_(4)-p LF is beneficial to the electrocatalytic process.This work will shed light on the development of nature-inspired carbon-based materials in hybrid electrocatalysts for OWS.
基金supported by the National Science Fund for Excellent Young Scholars (51722103)the Natural Science Foundation of China (51571149)
文摘Hydrogen evolution reaction (HER) is an essential step in converting renewable energy to clean hydrogen fuel. Exploring highly efficient, stable and cost-effective electrocatalysts is of crucial significance for sustainable HER. Here, we report the design of a coupled ruthenium/cobalt oxide (Ru/CoO) hybrid electrocatalyst for alkaline HER. In this hybrid metal/oxide system, the complicated alkaline HER pathways are overall facilitated;oxygen (O)-vacancy-abundant oxide enhances water splitting and Ru promotes successive hydrogen intermediates to generate hydrogen. The resulting Ru/CoO hybrid electrocatalyst exhibits significantly promoted catalytic activity compared with benchmark Ru catalyst, displaying an overpotential of 55 mV to generate a HER current density of 10 mA cm^-2, comparable with the state-of-the-art Pt/C catalyst and the most efficient alkaline HER electrocatalysts. Furthermore, the strong interaction of Ru nanoparticles with oxide support and the in-situ growth of oxide support on conductive substrate guarantee the long-term stability of as-fabricated Ru/CoO hybrid electrocatalyst. This newly designed hybrid catalyst with abundant metal/oxide interfaces may pave a new pathway for exploring efficient and stable HER electrocatalysts.
文摘Hydrogen is widely regarded as a crucial energy carrier for achieving carbon neutrality and a sustainable future.Direct seawater electrolysis using renewable energy presents a promising approach for large-scale hydrogen production.Reactions of this nature at high current density and Faradaic efficiency are hampered by two challenges.
基金financially supported by Shandong Provincial Natural Science Foundation,China (ZR2017MB059)the National Natural Science Foundation of China (21776314)the Fundamental Research Funds for the Central Universities (18CX05016A)
文摘Developing transition metal-based electrocatalysts with rich active sites for water electrolysis plays important roles in renewable energy fields. So far, some strategies including designing nanostructures, incorporating conductive support or foreign elements have been adopted to develop efficient electrocat- alysts. Herein, we summarize recent progresses and propose in-situ electrochemical activation as a new pretreating technique for enhanced catalytic performances. The activation techniques mainly comprise facile electrochemical processes such as anodic oxidation, cathodic reduction, etching, lithium-assisted tuning and counter electrode electro-dissolution. During these electrochemicaI treatments, the catalyst surfaces are modified from bulk phase, which can tune local electronic structures, create more active spe- cies. enlarge surface area and thus improve the catalytic performances. Meanwhile, this technique can couple the atomic, electronic structures with electrocatalysis mechanisms for water splitting. Compared to traditional chemical treatment, the in-situ electrochemical activation techniques have superior advantages such as facile operation, mild environment, variable control, high efficiency and flex- ibility. This review may provide guidance for improving water electrolysis efficiencies and hold promis- ing for application in many other energy-conversion fields such as supercapacitors, fuel cells and batteries.
基金funding support from the National Key Research and Development Program of China (2019YFE0123400)the Tianjin Distinguished YoungScholars Fund (20JCJQJC00260)+3 种基金the "111" Project (B16027)funding support from the Villum Foundation V-SUSTAIN Grant 9455funding from the European Union's Horizon 2020 research and innovation program through a Marie Sklodowska-Curie postdoctoral fellowship under grant agreement 844288 (STRATCAT-CO_(2))scholarship from the China Scholarship Council。
文摘Bimetallic Cu-In hybrid electrocatalysts are promising noble metal-free catalysts for selective electrochemical CO_(2) reduction reaction(ECO_(2) RR).Most reports show Cu-In catalysts are selective towards CO evolutio n.However,few show similarly high selectivity towards formate.Herein we fabricated composition tunable Cu-In hydroxides(Cu_xIn_y-OH) by the hydrothermal method and studied their composition effect on electrochemical CO_(2) reduction in detail. We found that the selectivity of CO_(2) reduction products shifted from CO to formate when the content of In increased in the Cu_xIn_y-OH electrocatalysts.The Cu rich electrocatalyst mostly produced CO,which could achieve a Faradaic efficiency(FE) to 75.8% at-0.59 V vs.RHE(Cu_(76)In_(24)based electrocatalysts).In comparison,the In rich electrocatalysts selectively produced formate,which possessed the FE of formate up to 85% at-1.01 V vs.RHE.Our work systematically illustrates the composition effect on hybrid catalysts,and provides insights into the design of highly selective catalysts for ECO_(2) RR.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(RS-2018-NR031063)in part by the Research Grant of Kwangwoon University in 2025.
文摘Abstract The polypyrrole（PPy）@NiCo hybrid nanotube arrays have been successfully fabricated as a high performance electrocatalyst for hydrogen evolution reaction （HER） in alkaline solution. The strong electronic interactions between PPy and NiCo alloy are confirmed by X-ray photoelectron spectroscopy and Raman spectra. Because these interations can remarkably reduce the apparent activation energy （Ea） for HER and enhance the turnover frequency of catalysts, the electrocatalytic performance of PPy@NiCo hybrid nanotube arrays are significantly improved. The electrochemical tests show that the PPy@NiCo hybrid catalysts exhibit a low overpotential of-186 mV at 10.0 mA·cm^-2 and a small tafel slope of 88.6 mV·deg^-1 for HER in the alkaline solution. The PPy@NiCo hybrid nanotubes also exhibit high catalytic activity and high stability for HER.
基金supported by the National Natural Science Foundation of China(21773163,21531006,22001021)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(KF2021005)+3 种基金Natural Science Foundation of Jiangsu Province(BK20201048)Natural Science Research Project of Higher Education Institutions in Jiangsu Province(20KJB150008)Collaborative Innovation Center of Suzhou Nano Science and Technologythe Project of Scientific and Technologic Infrastructure of Suzhou(SZS201905)。
文摘Metal-organic frameworks possessing relatively large pores,high surface areas,and unsaturated metal sites are attractive materials for use as electrocatalysts in the reduction of N_(2)to NH_(3).In this work,a MIL-101(Fe)/MoS_(3)hybrid catalyst,prepared by using a precursor-transformation strategy,is shown to be an effective electrocatalyst for the N_(2)reduction reaction(NRR).Under solvothermal conditions,micro-sized octahedral MIL-101(Fe)precursors are converted into ultra-small nanodots,while amorphous MoS_(3)derived from(NH_(4))_(2)MoS_(4)provides a surface suitable for anchoring the MIL-101(Fe)nanodots.The asprepared composite exhibits excellent electrocatalytic activity and durability for the NRR with a Faraday efficiency of 36.71%and an NH_(3)yield of 25.7μg h^(-1)mg_(cat)^(-1)at-0.1 V vs.RHE in 0.1 M HCl.The results show that the dispersion and adherence of MIL-101(Fe)nanodots on amorphous MoS_(3)improves the exposure of active centers and aids mass transfer,resulting in greatly enhanced catalytic activity and stability.
基金National Research Foundation of Korea,Grant/Award Numbers:2022R1A2C1012419,2022R1A2C1011559,2022R1C1C1007004。
文摘Electrochemical nitrogen reduction reaction(NRR)is a sustainable alterna-tive to the Haber-Bosch process for ammonia(NH3)production.However,the significant uphill energy in the multistep NRR pathway is a bottleneck for favorable serial reactions.To overcome this challenge,we designed a vanadium oxide/nitride(V_(2)O_(3)/VN)hybrid electrocatalyst in which V_(2)O_(3)and VN coex-ist coherently at the heterogeneous interface.Since single-phase V_(2)O_(3)and VN exhibit different surface catalytic kinetics for NRR,the V_(2)O_(3)/VN hybrid elec-trocatalyst can provide alternating reaction pathways,selecting a lower energy pathway for each material in the serial NRR pathway.As a result,the ammo-nia yield of the V_(2)O_(3)/VN hybrid electrocatalyst was 219.6µg h^(-1)cm^(-2),and the Faradaic efficiency was 18.9%,which is much higher than that of single-phase VN,V_(2)O_(3),and VNxOy solid solution catalysts without heterointerfaces.Density functional theory calculations confirmed that the composition of these hybrid electrocatalysts allows NRR to proceed from a multistep reduction reaction to a low-energy reaction pathway through the migration and adsorption of interme-diate species.Therefore,the design of metal oxide/nitride hybrids with coherent heterointerfaces provides a novel strategy for synthesizing highly efficient elec-trochemical catalysts that induce steps favorable for the efficient low-energy progression of NRR.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 21105079 and 21405119）, the Fundamental Research Funds for the Central Universities of China （Nos. 0109-1191320016 and cxtd2015003）, the Scientific Research Foundation for the Returned Overseas Chinese Scholars by the State Education Ministry of China, and the Interna- tional Science and Technology Cooperation and Exchange Program of Shaanxi Province of China （No. 2016KW-064）. Yaping Du gratefully acknowledgesthe financial support from the start-up funding from Xi＇an Jiaotong University, the Fundamental Research Funds for the Central Universities of China （No. 2015qngz12）, and the the National Natural Science Foundation of China （Nos. 21522106 and 21371140）.
文摘Developments of nanostructured transition metal dichalcogenides （TMDs） materials as novel electrocatalyst candidates for oxygen reduction reaction （ORR） is a new strategy to promote the developments of non-precious metal ORR catalysts. In this work, a three-dimensional （3D） hybrid of rosebud-like MoSe2 nanostructures supported on reduced graphene oxide （rGO） nanosheets was successfully synthesized through a facile hydrothermal strategy. The prepared MoSe2@rGO hybrid nanostructure showed enhanced electrocatalytic activity for the ORR in alkaline medium compared to that of the pure MoSe2, rGO, and their simple physical mixture, which could benefit from the excellent oxygen adsorption ability of the abundantly exposed active edge sites of the ultrathin MoSe2 layers, the conductivity and aggregation-limiting effect of the rGO platform, as well as the unique 3D rosebud-like architecture of the hybrid material. The electrocatalytic activity of the MoSe2@rGO hybrid towards ORR was comparable to that of com- inertial Pt/C catalysts. And the promoted reaction was revealed to involve a nearly four-electron-dominated ORR process by analysis of the obtained Koutecky- Levich plots. The scanning electrochemical microscopy （SECM） technique, with the advantages of investigating of the local catalytic activity of samples with high spatial resolution and simultaneously evaluating activities of different catalysts in a single experiment, was further applied to investigate the local ORR electrocatalytic activity of MoSe2@rGO and compare it with those of other catalyst samples through applying different sample potentials. The excellent stability and methanol tolerance of the 3D nanostructured MoSe2@rGO hybrid against methanol further prove the 3D nanostructured MoSe2@rGO hybrid as a promising ORR electrocatalyst in alkaline solution for potential applications in fuel cells and metal-air batteries.
