The Critical Role of Coordination Interaction between Hole Scavenger and ZnIn2S4 for Photocatalytic Hydrogen Evolution

Abstract

Hole scavenger plays a crucial role in the photocatalytic hydrogen evolution reaction (HER), yet the principle guiding its selection remains controversial. In our study, we evaluate the photocatalytic HER performance of ZnIn₂S₄ (ZIS) with ten commonly used hole scavengers, and surprisingly find that the HER efficiency is dependent on the coordination interaction between the hole scavenger and the photocatalyst, rather than the commonly recognized redox potential of the scavengers. This coordination interaction can be quantitatively interpreted using the adsorption energy (AE) as a key metric. Notably, a scaling relationship is established between the calculated AE and the experimentally observed photocatalytic H₂ evolution rate (H_rate). Among the ten investigated hole scavengers, triethanolamine demonstrates the strongest coordination interaction with ZIS, leading to the highest photocatalytic H_rate of 226.67 μmol h^–1. As such, this work offers a valuable guideline for the rational selection of hole scavengers in a given photocatalytic system.