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 H₂ 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 H₂ evolution in alkaline solutions.