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

• Electron transfer dynamics of CdS/Pt schottky junction photocatalyst is studied by femtosecond transient absorption spectroscopy. • Lactic acid results in the fastest electron transfer rate of 1.8 × 10⁹ s^–1 at the CdS/Pt interface. • The CdS/Pt interface with lactic acid as the electron donor achieves the highest interfacial electron transfer efficiency of 76%. • The function of electron donor during photocatalytic H 2 production is revealed from the perspective of electron transfer dynamics. Electron donors (EDs) are widely used to improve the H 2 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 H 2 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 H 2 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. [ABSTRACT FROM AUTHOR]