Visualization of Active Sites for Plasmon-Induced Electron Transfer Reactions Using Photoelectrochemical Polymerization of Pyrrole

Spatially selective deposition of conductive polymer was observed at the Au nanostructures supported on TiO2 electrodes via plasmon-induced photopolymerization of pyrrole monomers. The reactions were triggered by the excitation of localized surface plasmon resonance under near-infrared light illumination to the plasmon-active Au nanostructures. The morphological characteristics of the deposited polypyrrole prove the localization of the reaction-active sites in the plasmon-induced oxidation-reaction system. In addition, the estimation of reaction characteristics provides information on the spatial distribution and the electrochemical potential of the holes to contribute to the reaction. The unique polymer-growing process observed in the present system provides information on the mechanism of plasmon-induced oxidation reaction occurring at the active sites.