Modulation of catalyst microenvironments in ZnIn2S4/g-C3N4 S-scheme heterojunction for ratio-tunable syngas production from CO2 photoreduction

Photocatalytic CO 2 reduction for syngas production holds immense promise in the realm of valuable chemical synthesis. However, its potential is significantly hindered by the sluggish dynamics and non-selective outputs of charge carriers, attributable to the intricate microenvironment of photocatalysts. Herein, a facile approach was proposed to enhance syngas production by fabricating S-scheme ZnIn 2 S 4 /g-C 3 N 4 (ZISCN) heterojunctions with strategically tailored microenvironments. Theoretical calculations and elaborate experimental results confirmed that modifying the interfacial microenvironment with C−S bonds manipulated the photoexcited charge dynamics, while adjusting the surface microenvironment with In vacancies created CO 2 adsorption sites, facilitating charge accumulations on ZIS surface. The modulation of catalyst microenvironments promoted the formation of COOH* and CHO* intermediates, thereby enabling efficient and controllable syngas production. Our findings establish a framework for the development of intricate heterojunction photocatalysts that leverage sunlight effectively for clean energy generation. • A S-scheme ZISCN heterojunction with In vacancy and C−S bond was obtained. • Modulation of interfacial microenvironment enhanced the charge dynamics. • Regulation of surface microenvironment promoted CO 2 adsorption. • Modifying catalyst microenvironment boosted the tunable production of syngas.