Molybdenum-modified ZnIn2S4 with Bifunctional Cocatalyst for Efficient Photocatalytic Overall Water Splitting under Simulated Sunlight

Photocatalytic overall water splitting (POWS) was a promising technique for sustainable hydrogen provision that could potentially tackle the current energy and environmental challenges. As a visible-light-active photocatalyst, ZnIn2S4 was an ideal candidate for POWS yet was characterized with a low efficiency due to poor charge separation and improper surface reactions. Here, ZnIn2S4 was modified by doping Mo and depositing with bifunctional cocatalyst for efficient POWS under sunlight. Charge separation and photodeposition of Pt and CrOx was accelerated by Mo introduction to promote surface POWS reactions and suppress reverse reactions. Under simulated sunlight irradiation, the modified ZnIn2S4 achieved POWS with an apparent quantum efficiency (AQE) of 0.17% at 420  20 nm and a solar-to-hydrogen (STH) conversion efficiency of 0.016%. Theoretical calculations indicated that Mo dopants introduced spin-polarized states at both conduction band bottom and valence band top, being spin-forbidden for charge recombination. This study served as a useful guideline for the design and development of efficient photocataysts for sunlight-driven POWS.