WO₃ Nanosheet/ZnIn₂S₄ S-Scheme Heterojunctions for Enhanced CO₂ Photoreduction

Abstract

The nanostructure of the photocatalyst plays a crucial role in determining its catalytic ability. In this paper, a 2D/2D WO 3 /ZnIn 2 S 4 Sscheme heterojunction was successfully prepared through a simple hydrogen reaction. Under UV−vis light irradiation, the yield of CO in the CO 2 photoreduction process using WO 3 /ZnIn 2 S 4 as the catalyst reached about 44.61 μmol•g −1 , which was about 3.9 times higher than that obtained with ZnIn 2 S 4 alone. Cycling experiments demonstrated that the binary composite exhibited excellent photocatalytic activity and material stability. Photoelectrochemical measurements revealed that the 2D/2D WO 3 /ZnIn 2 S 4 Sscheme heterojunction significantly enhanced the separation efficiency of photogenerated carriers and effectively improved the redox ability of the photocatalyst. Density functional theory calculations were employed to analyze the electron transfer pathways and the formation of the built-in electric field at the 2D/2D WO 3 /ZnIn 2 S 4 interface, confirming that the heterojunction structure accelerated the transfer of photogenerated electrons from WO 3 to ZnIn 2 S 4 . The CO 2 photoreduction process was further investigated by in situ FTIR. Finally, a possible S-scheme electron transfer mechanism at the 2D−2D WO 3 /ZnIn 2 S 4 interface during the CO 2 photoreduction reaction was proposed and discussed.

Hierarchical (CdZnCuCoFe)S1.25/ZnIn2S4 Heterojunction for Photocatalytic CO2 Reduction: Insights into S-Scheme Charge Transfer Pathways in Type-I Band Alignment

“…Recently, the S-scheme heterojunction, comprising both oxidation and reduction photocatalysts, has emerged as a promising approach to achieve efficient electron–hole pair separation and strengthen the redox ability of the surviving charge carriers, thereby boosting photocatalytic performance . To date, numerous semiconductors such as g-C 3 N 4 , , various metal oxides, − and ZnS have served as candidates to fabricate S-scheme heterojunctions with ZIS for CO 2 photoreduction. , For instance, Zhang’s group synthesized an S-scheme heterojunction by growing ZnIn 2 S 4 nanosheets on the surface of TiO 2 hollow spheres . The heterojunction achieved a total photocatalytic CO 2 reduction (the sum yield of CO, CH 3 OH, and CH 4 ) of 18.32 μmol g –1 h –1 , indicating a 2.75 and 4.43 times increase compared with pristine ZnIn 2 S 4 and TiO 2 , respectively.…”