Plasmonic Photocatalyst for H2 Evolution in Photocatalytic Water Splitting

The effect of surface plasmon resonance (SPR) on the photocatalytic water splitting was studied by employing the photocatalyst, Au/TiO2, to produce renewable solar hydrogen. It is well-known that metal particles on TiO2 can behave as electron traps, retarding the recombination of electron−hole pairs, thereby improving reaction activity. However, the electron trap is not the only mechanism responsible for the photoreaction enhancement. Our experiment on methylene blue photodegradation over Au particles proved that the SPR phenomenon was also involved in the photoreaction enhancement. Furthermore, the photocatalytic water splitting was performed on Au/TiO2 prepared by the photodeposition method. The production of hydrogen was significantly increased because Au particles not only acted as electron traps as well as active sites but also played an important role in the SPR enhancement. The intensified electric field at the interface between the Au particle and the subdomain on TiO2 was illustrated by finite element method (FEM) electromagnetic simulation.