Facilely tunable dodecahedral polyoxometalate framework loaded with mono- or bimetallic sites for efficient photocatalytic CO2 reduction

Utilizing solar energy to drive the conversion of CO2 into high-value chemicals emerged as a promising approach to decrease CO2 emission. Yolk-shell or hollow structure have drawn much attention for photocatalytic CO2 reduction, owing to their efficient CO2 trapping and more active sites exposing. In this study, we employed a simple method to regulate the morphological evolution of K3PW12O40 dodecahedra. After annealing, mono-/bimetallic active species are homogeneously dispersed on K3PW12O40 framework forming PW12@Co and PW12@CoNi, which exhibit good CO production rates of 11.2 and 15.1 μmol/h, respectively, with selectivity of 90.7% and 92.6%. The differences in the activity and selectivity of CO2RR are attributed to the morphology variations of POM and the influence of mono-/bimetallic species. These results are confirmed through the analysis of SEM, TEM, N2 and CO2 adsorption/desorption, PL, EIS and SPV characterizations. In-situ DRIFTS and DFT provide further support for the formation and transformation of intermediate products.