Surface oxygen vacancies promoted Pt redispersion to single-atoms for enhanced photocatalytic hydrogen evolution

Abstract

Isolating metal atoms on supports for catalysis has attracted great attention of researchers due to the unique catalytic properties. Here we show by utilizing the hydrogen spillover effect at high temperature (700 °C) that the in situ formed surface oxygen vacancies on TiO₂ nanobelts can facilitate the redispersion of Pt nanoparticles to stable single-atoms. The isolated Pt atoms are firmly confined by the surface oxygen vacancy sites in the internal surface of TiO₂. Density functional theory (DFT) calculations have further proved that Pt atom is likely to be confined to oxygen vacancies to form single-atom sites. The as-obtained catalyst exhibits excellent photocatalytic water splitting performance with a hydrogen evolution rate of 38.33 mmol mg_Pt⁻¹ h⁻¹ under simulated solar light irradiation, which is about 59.9 times higher than that of TiO₂ nanobelts with Pt nanoparticles. This approach provides a facile method to prepare noble metal catalysts with both high atom economy and reaction activity.