Surface Phosphate Functionalization for Boosting Plasmon-Induced Water Oxidation on Au/TiO<sub>2</sub>
Bin Zeng, Shengyang Wang, Yejun Xiao, Guang Zeng, Xianwen Zhang, Rengui Li, Can Li
Abstract
Plasmonic photocatalysts suffer from inefficient charge separation and slow reaction kinetics, which result in poor plasmonic photocatalytic performance, especially for the hot hole involved water oxidation. Constructing a hot hole transfer chain and reaction center on plasmonic photocatalysts enables exciting opportunities for efficient plasmon-induced water oxidation. However, it is still challenging to modulate the behavior of the hot holes owing to the fast relaxation dynamics and low mobility. Herein, by introducing a surface phosphate group to functionalize the surface of the plasmonic photocatalyst Au-TiO2, the activity of hot hole involved water oxidation increases to ∼3 times as compared to the pristine photocatalyst. The optimized apparent quantum efficiency for plasmon-induced water oxidation was measured to be 1.2% at 520 nm. It is found that the plasmon-induced hot holes can be trapped by the phosphate anchored on the TiO2 surface for efficient steady charge separation, and the surface phosphate functionalization also results in a different multi-hole reaction pathway as compared to the Au/TiO2. This study provides an alternative way to modulate the hot hole’s separation and catalytic reactions in plasmonic photocatalysis.