Enhanced photocatalytic activity in Ag-nanoparticle-dispersed BaTiO3 composite thin films: Role of charge transfer

Optical absorption and photocatalytic activity can be enhanced by surface plasmon resonance (SPR) effect, but the charge transfer (CT) mechanism between the dispersed noble metal nanoparticles (NPs) and the semiconductor matrix has been ignored. Herein, we adduce a direct and strong evidence in Ag-nanoparticle-dispersed BaTiO3 (Ag/BTO) composite films through X-ray photoelectron and photoluminescence spectra which reveals the CT from BTO trapped by Ag NPs under UV light and from Ag NPs to BTO under visible light. Owing to the broadened optical absorption and efficient CT from Ag NPs to BTO, the Ag25/BTO film manifests the optimal photocatalytic activity under the irradiation of visible light rather than UV-Vis light. Our work provides a helpful insight to design highly efficient plasmonic photocatalyst through considering the synergetic effect of the CT between metal and semiconductor on the enhanced photocatalytic activity.