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
Scanning electrochemical microscopy represents a powerful tool for electro（chemical） characterization of surfaces, but its applicability has been limited in most cases at microscale spatial resolution, and the great...Scanning electrochemical microscopy represents a powerful tool for electro（chemical） characterization of surfaces, but its applicability has been limited in most cases at microscale spatial resolution, and the greatest challenge has been the scaling down to the nanoscale for fabrication and the use of nanometer-sized tips. Here, Pt nanoelectrodes with nanometer electroactive area were fabricated and employed for imaging a distribution of gold nanoparticles （AuNPs） and bioelectrocatalytic activity of a redox-active enzyme immobilized on gold surfaces.展开更多
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.
文摘Scanning electrochemical microscopy represents a powerful tool for electro（chemical） characterization of surfaces, but its applicability has been limited in most cases at microscale spatial resolution, and the greatest challenge has been the scaling down to the nanoscale for fabrication and the use of nanometer-sized tips. Here, Pt nanoelectrodes with nanometer electroactive area were fabricated and employed for imaging a distribution of gold nanoparticles （AuNPs） and bioelectrocatalytic activity of a redox-active enzyme immobilized on gold surfaces.
