Boosting Photocatalytic Hydrogen Evolution Activity by Accelerating Water Dissociation over Rh/Zn(OH)₂ Catalyst in Alkaline Solution

In the present work, we report that a Rh/Zn(OH) 2 catalyst, prepared by an in situ photodeposition strategy, can enhance water dissociation kinetics to boost the photocatalytic hydrogen evolution reaction (HER) in the mild alkaline environment. In comparison to a Rh NP catalyst, the Rh/Zn(OH) 2 catalyst exhibited a 3-fold increase in the rate of H 2 evolution. In-depth characterization manifests that the impressive photocatalytic performance was ascribed to multiple factors. First, the strong interaction between Rh nanoparticles (NPs) and Zn(OH) 2, coupled with the 3D network structure of amorphous Zn(OH) 2 for Eosin Y (EY) molecule adsorption, ensured the rapid transfer of photogenerated carrier pairs. Second, the kinetics of water dissociation over the Rh/Zn(OH) 2 catalyst was accelerated in the mild alkaline solution. As a result, the Rh/Zn(OH) 2 catalyst achieved a high HER rate of 60.9 mmol·g –1 ·h –1, and the apparent quantum efficiency (AQE) reached 79.5% at 430 nm. Overall, our work will expand the candidate materials to design high-performance catalysts for photocatalytic H 2 evolution in alkaline solutions.