Highly efficient and selective photocatalytic CO2 reduction using MIL-125(Ti) and based on LiFePO4 and CuO QDs surface–interface regulation

Abstract

In this study, CuO quantum dots were encapsulated in a MIL-125(Ti) MOF via a simple oxidation method. Upon loading of LiFePO₄ the composite material LiFePO₄/CuO@MIL-125(Ti) was formed. Due to the protection of the MIL-125(Ti) MOF, the composite photocatalyst exhibited stability in water. LiFePO₄ provided transferable electrons to the CuO QDs which significantly improved the efficiency and selectivity of the photocatalytic CO₂ reduction. Experiments showed that, at an optimal ratio of 2.5% LiFePO₄/1.0% CuO@MIL-125(Ti), the photocatalyst had its highest photocatalytic reduction activity for CO₂ conversion in the presence of water. The optimized photocatalyst gave yields of methanol, ethanol, and acetic acid of up to 445.38, 966.36, and 844.63 μmol g⁻¹, respectively. This work delivered a robust route for embedding CuO QDs and lithium battery materials into the surface matrix of photocatalysts for the effective reduction of CO₂.