Photothermal Catalysis Synergy Enhances the H2 Evolution Performance of NiS/ZnIn2S4 Nanosheet Film from Macro to Micro

Photothermal catalysis (PTC) water splitting outperforms traditional photocatalysis, but understanding of the photothermal/photochemical coupling mechanism is limited, hindering improvements in solar energy conversion efficiency. We grafted NiS ultrafine nanoparticles on hydrothermal-prepared ZnIn 2 S 4 nanosheet film via a photo-deposition process. Metallic NiS acts as photothermal/photochemical active sites and enhances solar light absorption and carrier separation of ZnIn 2 S 4 , achieving 41.14% photothermal conversion efficiency. The NiS/ZnIn 2 S 4 film exhibits a high and stable PTC H 2 production rate of 31.19   mmol·m -2 ·h -1 , which was 7.1 and 3.8 times higher than that of the pristine ZnIn 2 S 4 and the Pt/ZnIn 2 S 4 film with the same cocatalyst content, respectively. Photothermal, PTC, photoelectrical testing and DFT calculations demonstrate that the photothermal effect and synergistic photothermal/photochemical coupling contribute to the high PTC performance of NiS/ZnIn 2 S 4 . Thermodynamically, the increased temperature of NiS/ZnIn 2 S 4 enhances carrier generation and reduces Gibbs free energy (ΔG H ) for H 2 adsorption/desorption. Kinetically, temperature gradients at macro and micro levels enhance H 2 diffusion and electron convergence near NiS. This investigation of photothermal catalysis synergy provides promising strategy for designing efficient solar-to-hydrogen energy conversion systems.