Enhanced electron transport in rutile TiO2 nanowires via H2S-assisted incorporation of dissolved silicon for solar-driven water splitting

Abstract

Si-doping is an effective approach to enhance the electron transport and the photocatalytic activity of photocatalyst. In this study, for the first time the silicate glass such as fluorine-doped tin oxide (FTO) glass substrate is used as the silicon source for preparing Si-doped TiO2 photoanodes. First, the rutile TiO2 nanowires (NWs) were grown on FTO glass substrates by hydrothermal reaction, accompanying with the gradual dissolution of glass to generate soluble Si dopant incorporated into TiO2 NWs. Second, the TiO2 NWs were reduced to form the Ti3+ by H2S reduction. Finally, the Si-doped TiO2 photoanodes with higher doping density was obtained by calcination. The visible photocatalytic activity of Si-doped TiO2 NWs photoanode towards water splitting increased about three times as compared with pure TiO2 NWs. Reduction by H2S resulted in the enhanced electron transport and massive increase in charge-carrier density. This work provides a novel paradigm for silicon doping in materials for accelerating their carrier transport and applications.