Molybdenum-modified ZnIn₂S₄ with a bifunctional cocatalyst for efficient photocatalytic overall water splitting under...

Photocatalytic overall water splitting (POWS) is a promising technique for sustainable hydrogen production that can potentially tackle the current energy and environmental challenges. As a visible-light-active photocatalyst, ZnIn₂S₄ is an ideal candidate for POWS; however, it exhibits low efficiency due to poor charge separation and improper surface reactions. Here, ZnIn₂S₄ was modified by doping Mo and depositing a bifunctional cocatalyst for efficient POWS under sunlight. Charge separation and photodeposition of Pt and CrO were 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 the conduction band bottom and the valence band top, which are spin-forbidden for charge recombination. This study served as a useful guideline for the design and development of efficient photocatalysts for sunlight-driven POWS.