Tuning structure and electronegativity of adjacent atoms of ZnIn2S4/Agx@GSH via Zn modification for enhanced photocatalytic hydrogen production

Designing efficient photocatalysts for photocatalysis hydrogen production is crucial for advancing green energy technologies. In this work, ZnIn 2 S 4 photocatalyst with an asymmetric Zn-Zn-S unit ring structure and abundant in S vacancies was achieved by precisely tuning the molar mass of the Zn ion source using ethylene glycol as the reaction solvent. Z-type heterojunction was constructed via the electrostatic assembly by combining silver clusters (Ag x @GSH) with ZnIn 2 S 4 to enhance charge separation and photocatalytic activity. The structural transition from S-Zn-S to Zn-Zn-S led to local charge redistribution. Meanwhile, S vacancies acted as electron traps, promoting the charge state change of S in the S H sites and significantly accelerates the hydrogen evolution reaction (HER). The composite catalyst Zn-Vₛ-ZIS/Ag x @GSH exhibited a hydrogen production rate of 18.4 mmol·g −1 ·h −1 , under acidic conditions with lactic acid as the sacrificial agent, which is 3.7 times higher than pristine ZnIn 2 S 4 . Density functional theory (DFT) calculations revealed that the Zn-Zn-S distortion and heterojunction formation synergistically enhanced charge transfer and hydrogen adsorption kinetics. This work provides a novel approach for tailoring ZnIn 2 S 4 -based photocatalysts and provides new insights into the design of high-performance heterojunction systems for solar energy conversion.