Enhancing CO2 photoreduction through unique 2D MOF-based heterostructures with metalloid doping

Abstract

Combining semiconductors with metal–organic frameworks (MOFs) holds significant potential for creating highly efficient systems for the photoreduction of CO₂. This study presents a novel methodology, wherein the design of a 2D/2D heterojunction photocatalyst is introduced, utilizing ZIF-8 nanosheets as the foundational material. The catalyst is built upon partially vulcanized CuO nanosheets, specifically tailored for the selective photoreduction of CO₂ to CO and CH₄. The resulting complexes not only offer abundant active sites and facilitate effective charge transfer/separation to drive CO₂ photoreduction, but also delay CO separation, thereby increasing the likelihood of eight-electron reactions leading to CH₄ production. Consequently, the CuS@CuO@ZIF-8 catalyst demonstrates significantly enhanced activity and exceptional selectivity in CH₄ production compared to CuO@ZIF-8 and other counterparts. Impressive CO and CH₄ evolution rates of up to 270.96 and 44.57 μmol g⁻¹ h⁻¹, respectively, and a CH₄ selectivity of 14.1% are achieved. The catalyst not only enhances the light-absorption capabilities of ZIF-8 and facilitates carrier transport and separation, but also improves the stability and carbon dioxide adsorption capacity of the catalyst. This research establishes an effective model for designing and producing two-dimensional gas–solid photocatalysts with enhanced charge separation through partial sulfidation, offering new insights into improving the photoreduction activity of CO₂.