Insights into the pivotal role of surface defects on anatase TiO2 nanosheets with exposed {001} facets for enhanced photocatalytic activity

The surface defects on the TiO2 nanosheets with high energy {001} facets were controlled. The surface adsorbed O increased with the increased hydrothermal temperature, while that for TiO2–400 decreased. PALS results TiO2–160 exhibits larger oxygen vacancy clusters and a low ratio of bulk defects to surface defects. The photocatalytic activity of TiO2–160 significantly enhances 26.48 times higher than P25. And TiO2–160 presents the highest photocurrent, lowest PL emission, and longest fluorescence lifetime. The pivotal role of surface defects on anatase TiO2 nanosheets with exposed high energy {001} facets has been revealed. It was the larger oxygen vacancy clusters on the {001} surface, coupled with a considerable concentration of surface defects that guaranteed the greatly promoting photocatalytic activity. Larger oxygen vacancy clusters provide pathway to facilitate the activation and transportation of active oxygen species, while a considerable surface defects can significantly decrease the recombination of photogenerated charge carriers in bulk defects.