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.