Construction of Co/Ni-modified P4Mo6 compounds for photocatalytic CO2 conversion

Photocatalytic carbon dioxide reduction reaction (CO2RR) is regarded as a prospective clean and sustainable measure to deal with the environmental problem. In this work, two {P4Mo6}-based compounds were successfully assembled under hydrothermal conditions, formulated as (HL1)8[Co(H7P4Mo6O31)2]·9H2O (1) and [Ni(L2)3]4·[Ni(H7P4Mo6O31)2]·12H2O (2) [L1 = 4-phenylpyridine; L2 = 2-(2-pyridyl)benzimidazole]. Single crystal X-ray diffraction (SCXRD) analysis shows that compounds 1 and 2 are both assembled on the basis of one [M(P4Mo6)2] (M = Co or Ni) unit with the hourglass-shaped structure. More interestingly, the suitable energy band structures of M (M = Co or Ni) species in {P4Mo6} clusters make the potential CO2 photoreduction of compound 1 is better than compound 2. Beside, the results show that CO yields are 1178.11 μmol g−1 h−1 (1) and 878.32 μmol g−1 h−1 (2) for 8 h irradiation.