Two 2D layered Co-modified Anderson-type polyoxometalate-based highly efficient photocatalysts for CO2 reduction

The design of efficient and low-price photocatalysts is an effective way to relieve excessive carbon dioxide emissions and energy dilemma. Polyoxometalates are ideal materials due to their adjustable structures and semiconductor-like properties. Limited by their light absorption capacity, it is a feasible way to construct inorganic-organic composite polyoxometalate-based photocatalysts. Here, two efficient Anderson-type polyoxometalate-based photocatalysts, (C10H9N2)·{[Co(H2O)2]·[H6CrMo6O24]}·4H2O (1), {[Co(H2O)3]·[Co(DAPSC)]2·[H6CrMo6O24]2}·11H2O (2) [2,6-diacetylpyridine bis(semicarbazone), abbr. DAPSC], were prepared by hydrothermal synthesis method. The structural analysis indicates that compounds 1 and 2 share similarities: {CrMo6} units were linked by cobalt ions to form two-dimensional (2D) frameworks. The addition of Co ions provided catalytic active center for the catalyst, compounds 1 and 2 exhibited promising yield into CO, as high as 3061.6 μmol g−1·h−1 and 9309.8 μmol g−1·h−1, respectively. Due to their excellent properties, Anderson-type POMs can be used as the basic units of photocatalysts. At the same time, four cycling tests prove the stability of compound 2 under a long reaction time.