Modulating Charge Accumulation via Electron Interaction for Photocatalytic Hydrogen Evolution: A Case of Fabricating Palladium Sites on ZnIn2S4 Nanosheets

It is desirable to regulate charge migration synergistically via atomic level decoration because it can construct active sites with both thermodynamic and kinetic advantages in photocatalytic hydrogen (H2) evolution. Here, a mild cation exchange-mediated strategy was applied to anchor palladium (Pd) cations in the ZnIn2S4 nanostructure, achieving an outstanding H2 evolution rate of 1236.4 μmol h–1 (λ ≥ 420 nm) accompanied by an apparent quantum efficiency of 60.06% (λ = 420 nm). Pd dopants act as both active sites and surface chemical state modulators, which help to balance *H adsorption thermodynamically. More importantly, in situ electron spin resonance and in situ XPS analysis reveal that the synergistic electron interaction brought by the Pd–S structure constructs an efficient transfer channel, leading to more delocalized photocarriers to the active sites for H2 evolution reaction. A feasible strategy is proposed in this study to improve the performance of photocatalysts from the viewpoint of Pd cation exchange. Simultaneously, synergistic electron interaction is verified to modulate charge accumulation at Pd substitution sites, providing substantiation and unique insights into the electronic structure modification of photocatalysts.