Engineering of visible light-activated ZnIn2S4/N-rGO S-scheme heterojunction photocatalyst for H2 generation

Abstract

The design of S-scheme heterojunction photocatalysts emerges as high-profile candidates for hydrogen (H2) generation. Herein, by integrating heterojunction creation and heteroatom-doping approaches, ZnIn2S4/N-rGO photocatalyst is synthesized using a hydrothermal process. Crystallinity, morphology, surface area, light absorption, interfacial interaction, and charge separation and migration properties of ZnI2S4/Nitrogen-doped reduced graphene oxide (ZnIn2S4/N-rGO) are analytically explored to authenticate its successful construction. Consequently, the H2 generation performance of ZnIn2S4/N-rGO reached 2847 µmolh-1g-1 under visible light illumination, which is about 9.7 and 1.6 times as high as that of ZnIn2S4 and ZnIn2S4/rGO, respectively, with efficient stability. ZnIn2S4/N-rGO exhibits enhancement in the optical response, promotes the surface area, and improves separation and transport of photoexcited electron/hole pairs, attributing to higher H2 generation activity. The S-scheme charge migration mechanism is authenticated through EPR spectra. The current study not only signifies that ZnIn2S4/N-rGO is an excellent photocatalyst for H2 generation but also offers a route to develop outstanding and stable photocatalysts by combining heterojunction creation and heteroatom-doping approaches.