Hot electron induced by exciting localized surface plasmon resonance (LSPR) in the nanostructure converses irradiation into photoelectron, which can be viewed as a promising approach for various research fields. However, there is no compelling argument to reveal correlation between plasmon-induced hot electron and reaction pathway. Herein, a model system was demonstrated to debunk the myth, in which frameless hexahedron Ag-Pt bimetallic nanostructures were acted as electrocatalysts to study LSPR effects on half reaction of fuel cell (e.g., oxygen reduction reaction) since fuel cell technology is regarded as a potential candidate to solve the growing problem related to the pollution caused by the increasing energy demand. By employing a customized rotating ring disk electrode (RRDE), plasmonic induced effects upon oxygen reduction are able to be realized while intermediate (hydrogen peroxide) of 2-electron pathway can be significantly suppressed owing to remarkably injecting hot electron into Pt. AgPt-30 sample could achieve a relatively high enhance ratio of about 4% in limiting current density and the best improvement ratio of approximately 12% under light excitation. In order to clarify the hot electron behaviors in present study, in-situ X-ray absorption spectrum (XAS) provided a proper approach to realize it, in which the intensity change in white line of Pt L3-edge proved a considerable hot electron injection from Ag into Pt by aid of LSPR excitation and permitted the hot electron successfully alter reaction toward 4-electron pathway of oxygen reduction reaction in AgPt-30 sample. These findings might be attributed to a fact that the induced hot electrons were pumped into the anti-bonding orbital of oxygen and further weaken the binding of oxygen, and thereby the oxygen reduction could be significantly altered toward 4-electron path.

Frameless hexahedron bimetallic nanostructure for electrochemically catalyzing oxygen reduction: Synergistic plasmic effects to alter reaction toward 4-electron pathway

251st National Meeting (2016)

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