In-Situ Charge Carrier Dynamics of Au-Decorated TiO2 Nanorods Toward Photoelectrochemical Water Oxidation

Abstract

TiO2 nanorod arrays have been widely used as photoanodes for conducting photoelectrochemical water splitting. Upon decoration with Au, the charge carrier separation of TiO2 can be improved to enhance the water oxidation efficiency. In addition, the plasmonic effect of Au can promote additional charge carrier generation for TiO2, increasing the photoelectrochemical efficiency as well. Interfacial charge dynamics play an important role in governing the photoelectrochemical efficiency of photoelectrodes. In particular, employing in-situ spectroscopic techniques to monitor charge dynamics of photoelectrodes under operation conditions is essential for realizing the veritable working mechanism. In this study, in-situ transient absorption spectroscopy is utilized to monitor the interfacial charge dynamics of Au-decorated TiO2 nanorods under photoelectrochemical operation conditions. The effect of applied bias on the charge carrier dynamics of Au-decorated TiO2 has been elucidated. In specific, the hole dynamics at the photoanode surface has been elucidated to establish the correlation with the photoelectrochemical performance.