Ligand-controlled bimetallic Co/Fe MOF xerogels for CO2 photocatalytic reduction

Abstract

As a promising material with porous structure and large surface area, metal organic xerogel (MOX) has got extensive attention in the field of CO2 photocatalytic reduction. The skeleton structure and pore morphology of organic xerogel framework materials contribute to the diffusion and transfer of CO2 molecules. In this work, we prepared a serial of bimetallic Co/Fe-MOX by one-step solvent method, which can provide sufficient adsorption sites for CO2 molecules. Meanwhile, the presence of cobalt and iron in Co/Fe-MOX enhances greatly not only the absorption and utilization of light energy in a synergistic manner, but also the separation and transfer of carriers. During the photocatalytic reduction process, the metal center of Co acts as major active site for photocatalysis. Therefore, the rapid conversion of CO2 to CO is promoted. The Co/Fe-MOX with a molar ratio of 1:3 exhibits a high CO yield (67 μmol g−1 h−1), about 8.4 times that of Fe-MOX with a single Fe center (8 μmol g−1 h−1), implying the metal center Co acts as the main active site. This work provides ideas for designing metal organic xerogel materials with polymetallic centers for efficient photoreduction of CO2.