Hollow nanoreactor with MoS2 encapsulated in ZnIn2S4: Spatially oriented distribution of MoS2 improves photothermal hydrogen production activity

The rational design of nanoreactors is of paramount importance for synergistically optimizing light absorption, photogenerated carrier separation efficiency, and surface reactions to enhance photothermal catalytic hydrogen production. In this study, we constructed a nanoreactor with spatially ordered distribution of MoS₂ on the inner surface of hollow ZnIn₂S₄ (ZIS) through a one-pot hydrothermal method. Benefiting from its scientifically designed architecture, the nanoreactor exhibits exceptional photothermal hydrogen evolution activity of 33.6 mmol g⁻¹ h⁻¹, which is 2.3-fold and 18.7-fold higher than those of pristine ZIS and MoS₂, respectively. UV–vis diffuse reflectance spectroscopy (UV–vis DRS) confirmed that the incorporation of MoS₂ extends the light absorption edge of the nanoreactor beyond 1000 nm, significantly enhancing the photothermal conversion efficiency of ZIS to 14.6 %. Thermal participation in the photothermal hydrogen evolution process reduced the apparent activation energy to 9.8 kJ mol⁻¹ (70.9 % lower than conventional ZIS), indicating that the photothermal effect improve the reaction kinetics effectively. This phenomenon aligns with the temperature-dependent time-resolved fluorescence spectroscopy results of the accelerated photogenerated carrier kinetics under thermal assistance. In situ Kelvin probe force microscopy (KPFM) detected a 0.2 eV increase in the Schottky barrier height of the optimized nanoreactor under photoexcitation, effectively suppressing carrier recombination. Combined with density functional theory (DFT) calculations, these results elucidate the existence of a built-in electric field at the nanoreactor interface, which not only inhibits charge recombination but also optimizes the Gibbs free energy of H* intermediate adsorption (0.11 eV), thereby intensifying surface catalytic reactions. This study elucidates the synergistic mechanisms of core-shell structures in enhancing light absorption, improving carrier separation efficiency, and optimizing surface reaction kinetics, providing theoretical guidance for the cooperative improvement of photothermal hydrogen production activity.