Photocatalytic reduction of carbon dioxide to methanol using a ruthenium trinuclear polyazine complex immobilized on graphene oxide under visible light irradiation

Abstract

A ruthenium trinuclear polyazine complex was synthesized and subsequently immobilized through complexation to a graphene oxide support containing phenanthroline ligands (GO-phen). The developed photocatalyst was used for the photocatalytic reduction of CO2 to methanol, using a 20 watt white cold LED flood light, in a dimethyl formamide–water mixture containing triethylamine as a reductive quencher. After 48 h illumination, the yield of methanol was found to be 3977.57 ± 5.60 μmol gcat−1. The developed photocatalyst exhibited a higher photocatalytic activity than graphene oxide, which provided a yield of 2201.40 ± 8.76 μmol gcat−1. After the reaction, the catalyst was easily recovered and reused for four subsequent runs without a significant loss of catalytic activity and no leaching of the metal/ligand was detected during the reaction.