Surface-Modified Zn3In2S6 for a Dual-Pathway Photocatalytic Hydrogen Peroxide Production.

Photocatalytic H2O2 production via a two-electron oxygen reduction reaction (ORR) represents a green and sustainable alternative to the conventional anthraquinone process for industrial H2O2 synthesis. Bimetallic sulfide Zn3In2S6 has emerged as a promising photocatalyst for H2O2 production, yet the efficiency remains to be promoted. In this work, we introduced an anionic surfactant, sodium dodecyl sulfate (SDS), into the hydrothermal reactant to achieve a surface-modified Zn3In2S6 with a high photocatalytic H2O2 production efficiency. The SDS modification alters the electron state and band alignments and promotes the formation of sulfur vacancies. Consequently, the SDS modification tactic not only enhances charge separation and migration but also switches the reaction pathway from an ORR-dominated route in the pristine Zn3In2S6 to a dual-pathway involving both ORR and water oxidation reaction (WOR). The optimized SDS0.5-Zn3In2S6 photocatalyst achieves a remarkable H2O2 production rate of 1066.13 μmol·g-1·h-1 in pure water without any sacrificial agents, which is 1.6 times that of the pristine Zn3In2S6. Moreover, under argon atmosphere, it exhibits a H2O2 production rate of 598.83 μmol·g-1·h-1, approximately three times that of unmodified Zn3In2S6, confirming the enhanced WOR contribution. This work presents a novel Zn3In2S6-based photocatalyst with dual reaction pathways for efficient photocatalytic H2O2 production.