Investigation of the Performance of Heterogeneous MOF-Silver Nanocube Nanocomposites as CO2 Reduction Photocatalysts by In Situ Raman Spectroscopy

Here, we fabricated two different heterogeneous nanocomposites, core-shell MOF-AgNC and corner MOF-AgNC, as photocatalysts for CO2 conversion by generating metal-organic frameworks (MOFs) on silver nanocube templates. These MOF-AgNC nanocomposites showed good CO2 adsorption features and high CO2 reduction reactivity. The performances of these MOF-AgNC nanocomposites in CO2 adsorption and CO2 reduction reactions can be characterized by in situ Raman spectrum measurement. The corner MOF-AgNC nanocomposite exhibited a faster CO2 adsorption rate than the core-shell MOF-AgNC nanocomposite, which was due to the higher surface area/volume ratio of the MOF in corner MOF-AgNC. The CO2 reaction reactivity and mechanisms (products of the reaction) of CO2 reduction also depended on the morphologies of MOF-AgNC nanocomposites, which were caused by different reaction environments at the interface between the MOF and AgNCs. The CO2 reduction reactivity of MOF-AgNC nanocomposites also exhibited high sensitivity to the irradiation intensity and wavelength, which was caused by the variation of the number of hot electrons and their positions in AgNCs with the irradiation intensity and irradiation wavelength, respectively. This method for the synthesis of heterogeneous nanocomposites should make it possible to design photocatalysts for various reactions by carefully designing the morphology and composition of nanocomposites.