Electron transfer dynamics in Schottky junction photocatalyst during electron donor-assisted hydrogen production

Abstract

Electron donors (EDs) are widely used to improve the H2 production performance of Schottky junction photocatalysts, but the functions of EDs are still unknown from the perspective of electron transfer dynamics. Herein, Pt nanocluster-decorated CdS nanorod is successfully prepared to construct a typical CdS/Pt Schottky junction. Pt nanoclusters with a diameter of ∼2 nm are deposited on the surface of CdS nanorods by in situ photoreduction at sub-zero temperature. The CdS/Pt photocatalyst using lactic acid shows a higher H2 production rate of 4762 μmol g–1 h–1 compared to that using methanol, triethanolamine, and glycerol. To understand the cause, the dynamics of photogenerated carriers in CdS/Pt photocatalysts during ED-assisted H2 production are revealed by femtosecond transient absorption spectroscopy. Among the four organic EDs, lactic acid enables the fastest electron transfer rate of 1.8 × 109 s–1 and the highest electron transfer efficiency of 76% at the CdS/Pt interface due to the most efficient hole consumption. This work sheds light on the importance of efficient interfacial electron transfer for improving the photocatalytic performance of Schottky junction photocatalysts.