Interface-Engineered Z-Scheme CoIn2S4/MoSe2 Heterostructure for Enhanced Charge Separation toward Bifunctional Photocatalytic H2 Production and O₂ Reduction

Abstract

Developing efficient artificial photocatalysts for biomimetic production of valuable molecules, especially eco-friendly commodity chemical H2O2 and energy carrier H2 fuel remains a key scientific and technological challenge. The majority of current photocatalysts still face many limitations related to limited active sites and poor charge separation and transport, which yield low conversion efficiency. Herein, we present an interface-engineered CoIn2S4/MoSe2 Zscheme heterostructure photocatalyst that exhibits enhanced charge separation and transfer via the Mo-S interface for these reactions. A simple, cost-effective synthesis protocol is designed to grow patches of CoIn2S4 nanosheets on pre-formed MoSe2 nanosheets. The CoIn2S4/MoSe2 system functions as an efficient photocatalyst for the green H2 production and two-electron oxygen reduction reaction (ORR) for high-value H2O2 synthesis. Constructing the junction between CoIn2S4 and MoSe2 significantly enhances photocatalytic H2 evolution to 30.24 mmol g⁻¹ h⁻¹, with an apparent quantum efficiency (AQE) of 34.7% at λ = 420 nm. The heterostructure also delivers a green pathway and a high H2O2 production rate of 19.60 mmol g⁻¹ h⁻¹ (AQE 420nm =11.2%) with minimal decomposition and excellent cycling stability.Overall, this study presents a strategy for designing interface-modulated, internal-fieldregulated, and selective multi-electron transfer-enabled Z-scheme heterostructures to achieve efficient photocatalytic H 2 production and ORR without the need for a cocatalyst.