Surface oxygen vacancies enriched Pt/TiO2 synthesized with a defect migration strategy for superior photocatalytic activity

Surface oxygen vacancies (Ovs) may act as growth centers for Pt nanoparticles (NPs) and stabilize Pt NPs to avoid spontaneous aggregation, which practically improves the photocatalytic activity of Pt/TiO2. In this work, a defect migration strategy is developed; that is, the number of surface Ovs on Pt/TiO2 is effectively increased by migrating bulk Ovs to the surface through a vacuum annealing process. The Ov-enriched surface of Pt/TiO2 increases the proportion of active Pt species (Pt0 and Pt-OH), thus greatly facilitating the photocatalytic activity of the catalyst under visible-light irradiation. Specifically, the apparent rate constant for the typical sample of Pt-Ovs/Ti3+/TiO2 (PVTT) prepared with the defect migration strategy is about 4.44 times as much as that for the control sample (Pt-TiO2) without the contribution of Ovs.