Site-Selective Deposition of a Cobalt Cocatalyst onto a Plasmonic Au/TiO2 Photoanode for Improved Water Oxidation

Abstract

Plasmonic Au/TiO2 thin film works as a stable water oxidation photoanode. Here we show that site-selective deposition of nanosized CoOx as a water oxidation cocatalyst at the edge of Au nanoparticles on the TiO2 film improves the photoelectrochemical water oxidation activity. The nanosized CoOx was deposited by a photoassisted electrochemical method onto the Au/TiO2 thin film. The CoOx loading amount was controllable by changing the amount of electric charge that flowed during the deposition, which influenced the photoelectrochemical performance. Under visible light, the optimized CoOx/Au/TiO2 thin film generated stable photoanodic current, which was similar to 3 times higher than that obtained using Au/TiO2.