Optimization of Hydrogen Evolution Performance in ZnIn 2 S 4 Photocatalysts via Ho‐Doped Induced Tensile Strain

The photocatalytic hydrogen evolution (PHE) is a crucial technique for converting solar energy into green hydrogen. However, the PHE efficiency remains limited by metal–acid site spacing. In this study, we present a lattice‐strain strategy to precisely control the distance between the metal and acid site by doping rare‐earth Ho atoms onto a ZnIn 2 S 4 nanosheet. Ho‐doped ZnIn 2 S 4 exhibits a hydrogen evolution rate of 1865.49 µmol g −1 h −1 under visible light, approximately 2.4 times that of the pure sample, with an apparent quantum efficiency of 14.7% at 420 nm. This performance is attributed to precise control of the distance between metal and acid sites via tensile strain induced by Ho, resulting in greatly improved charge‐transfer capability and reduced energy barrier of the reaction. This work provides new insights into the design of highly efficient photocatalysts via strain engineering, revealing the role of the metal–acid site distance as a crucial structural parameter in the synergistic regulation of charge dynamics and the thermodynamics of hydrogen evolution.