Unraveling the solar and visible light-induced deactivation mechanism of Pt-decorated carbon/TiO2 nanocomposite in photocatalytic hydrogen production

Photocatalytic water splitting presents an attractive and environmentally friendly method for generation of "green" hydrogen. However, the most widely used photocatalyst for hydrogen production, Pt-doped TiO2, has low stability, thus limiting its application for long term performance. In this study, the deactivation mechanism of Pt-decorated carbon TiO2 nanocomposite photocatalysts during photocatalytic hydrogen production was thoroughly investigated under solar and visible light irradiation. Solar light irradiation promoted markedly higher H2 production activity, however with lower catalyst stability. Deactivation studies using fresh catalysts/deactivated solutions and deactivated catalysts/fresh solutions point out the effect of the light used on the catalyst stability through changes on the catalyst surface as well as by the kinetics of intermediate/products formation during the reaction course. The present study revealed the importance of charge transport direction between TiO2, carbon and Pt on catalyst activity and stability and highlights the difference in visible and solar light-induced hydrogen production. [Display omitted]