Full-Space Electric Field in Mo-Decorated Zn₂In₂S₅ Polarization Photocatalyst for Oriented Charge Flow and Efficient Hydrogen Production.

Abstract

Integration of photocatalytic hydrogen (H₂) evolution with oxidative organic synthesis presents a highly attractive strategy for the simultaneous production of clean H₂ fuel and high-value chemicals. However, the sluggish dynamics of photogenerated charge carriers across the photocatalysts result in low photoconversion efficiency, hindering the wide applications of such a technology. Herein, this work overcomes this limitation by inducing the full-space electric field via charge polarization engineering on a Mo cluster-decorated Zn₂In₂S₅ (Mo-Zn₂In₂S₅) photocatalyst. Specifically, this full-space electric field arises from a cascade of the bulk electric field (BEF) and local surface electric field (LSEF), triggering the oriented migration of photogenerated electrons from [Zn-S] regions to [In-S] regions and eventually to Mo cluster sites, ensuring efficient separation of bulk and surface charge carriers. Moreover, the surface Mo clusters induce a tip enhancement effect to optimize charge transfer behavior by augmenting electrons and proton concentration around the active sites on the basal plane of Zn₂In₂S₅. Notably, the optimized Mo_1.5-Zn₂In₂S₅ catalyst achieves exceptional H₂ and benzaldehyde production rates of 34.35 and 45.31 mmol g_cat ^-1 h^-1, respectively, outperforming pristine ZnIn₂S₄ by 3.83- and 4.15-fold. These findings mark a significant stride in steering charge flow for enhanced photocatalytic performance.