Photoreduction of CO2 to methanol with hexanuclear molybdenum [Mo6Br14]2− cluster units under visible light irradiation

Abstract

Octahedral molybdenum clusters were found to be efficient visible light homogeneous photocatalysts for the reduction of carbon dioxide (CO2) to methanol. Photoreduction was carried out by using 20 watt white cold LED flood light in dimethyl formamide/water or acetonitrile/water solutions containing triethylamine as a reductive quencher. Among the two cluster-based compounds, Cs2[Mo6Br14] exhibited higher photocatalytic efficiency and afforded higher yield of methanol than (TBA)2[Mo6Br14] (TBA = tetrabutylammonium). After 24 h illumination, the yield of methanol was 6679.45 and 5550.53 μmol g−1 cat. using Cs2[Mo6Br14] and (TBA)2[Mo6Br14] cluster compounds as photocatalysts, respectively.