New insight into ZnO@ZIFs composite: an efficient photocatalyst with boosted light response ability and stability for CO2 reduction.

Abstract

One of the main causes of climate change and energy exhaustion is the excessive use of fossil fuels. Photocatalytic carbon dioxide (CO2) reduction technology uses inexhaustible sunlight to directly convert CO2 into value-added chemicals or fuels not only solving the problem of greenhouse effect but also alleviating the shortage of fossil energy. In this work, a well-integrated photocatalyst is synthesized through growing zeolitic imidazolate frameworks (ZIFs) with different metal nodes on ZnO nanofiber (NFs) for CO2 reduction. One-dimensional (1D) ZnO NFs have better CO2 conversion efficiency due to the high surface-to-volume ratio and low light reflectivity. 1D nanomaterials with superior aspect ratios can be assembled into free-standing flexible membranes. In addition, it has been found that ZIFs nanomaterials with bimetallic nodes not only have better CO2 reduction capabilities but also exhibit superior thermal and water stability. The photocatalytic CO2 conversion efficiency and selectivity of ZnO@ZCZIF are shown to be significantly enhanced which can be attribute to the strong CO2 adsorption/activation, efficient light capture, excellent electron-hole pair separation efficiency, and specific metal Lewis sites. This work provides insights into the rational construction of well-integrated composite materials to improve the photocatalytic carbon dioxide reduction performance.