Synthesis of a highly active core–shell Ni-MOF@CdS S-scheme heterojunction for enhanced photoreduction of CO2 to CO

Abstract

One of the attractive applications of metal–organic frameworks (MOFs) is the photocatalytic transformation of CO₂ into clean fuels or high value chemicals due to their high CO₂ adsorption capacity. However, the fast recombination process of electrons and holes in MOFs has limited their activity. Herein, a novel core–shell Ni-MOF@CdS S-scheme heterojunction was designed and fabricated to improve the carrier separation for achieving a high CO₂ reduction activity. Among the prepared photocatalysts, the optimum Ni-MOF@CdS 30% sample demonstrated the highest yield of CO (24.1 μmol g⁻¹), which was almost 3 and 2.5 times higher than those of bare CdS and Ni-MOF samples. This improvement of photoreduction of CO₂ to CO might be related to the synergistic effect of the core–shell structure and the S-scheme carrier transfer mode, which improved the charge separation efficiency, retained strong reduction capacity, and provided abundant active sites for the selective photoreduction process. Our work provides a new strategy to design future MOF based nanocomposites for the efficient photoreduction of CO₂.