2d/2d Step-Scheme Fese2/Biobr0.5cl0.5 Heterostructures for Photocatalytic Hydrogen Generation at Atmospheric Pressure

Abstract

Photocatalytic hydrogen evolution from water splitting is one of the promising strategies to achieve carbon neutrality, constructing S-scheme heterojunction effectively facilitates photocarriers separation and improves reaction activity. Here, a novel 2D/2D step-scheme FeSe2/BiOBr0.5Cl0.5 heterostructure is rationally constructed according to a successive hydrothermal method of BiOBr0.5Cl0.5 followed by in-situ hot injection process of FeSe2. The optimized 5% FeSe2/BiOBr0.5Cl0.5 composite exhibits the moderate photocatalytic hydrogen evolution rate of 374.4 μmol·g-1·h-1 at normal atmospheric pressure (0.1 MPa) under light irradiation. The photocarriers separation and transfer behaviors, HER processes are detailedly investigated. The significantly enhanced HER activity may arise from strong light absorption capability, increased contact area and exposure of reaction sites, along with accelerated charge carrier separation and enhanced redox capability through the S-scheme charge transfer pathway. This work provides a promising strategy for the development and design of efficient photocatalytic systems for hydrogen evolution and the guided transport of charge carriers in 2D/2D step-scheme heterostructure systems.

Keywords: FeSe2, BiOBr0.5Cl0.5, 2D/2D heterojunction, S-scheme, H2 evolution.