Zn single-atom loaded TiO2 derived from Ti-MOF for high hydrogen evolution activity under visible light

TiO 2 has emerged as one of the most extensively studied photocatalysts, because of its great stability and abundant availability. The hydrogen production efficiency of TiO 2 photocatalysts can be significantly enhanced derived from the precursors of titanium-based metal-organic frameworks (MOFs) loaded with single-atom. Although the hydrogen evolution activity of TiO 2 -based photocatalysts under ultraviolet light has been steadily enhanced in recent years, the activity under visible light remains a critical challenge to be addressed. Herein, we report a Zn single atom (Zn SA) loaded TiO 2 -based photocatalyst derived from Ti-BPDC (Ti-MOF). Under irradiation with visible light at 400 nm, the optimized sample exhibits a hydrogen evolution rate (HER) of 9.21 mmol g −1  h −1 with an apparent quantum efficiency (AQE) of 6.82%, with a HER approximately 3 times higher than that of pristine TiO 2 (3.14 mmol g −1  h −1 ), along with great stability. The results demonstrate that loading an appropriate amount of Zn SAs optimizes the band structure of the photocatalyst, activates the adjacent O atoms, and also suppresses the recombination of photogenerated electron-hole pairs, as well as modulates the adsorption-desorption equilibrium of H∗ species, thereby significantly enhancing photocatalytic activity. This work offers a strategy for designing TiO 2 -based photocatalysts with high visible-light activity.