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

A ruthenium trinuclear polyazine complex was synthesized and subsequently immobilized throughcomplexation to a graphene oxide support containing phenanthroline ligands (GO-phen). The developedphotocatalyst was used for the photocatalytic reduction of CO2 to methanol, using a 20 watt white coldLED flood light, in a dimethyl formamide–water mixture containing triethylamine as a reductivequencher. After 48 h illumination, the yield of methanol was found to be 3977.57 5.60 mmol gcat1.The developed photocatalyst exhibited a higher photocatalytic activity than graphene oxide, whichprovided a yield of 2201.40 8.76 mmol gcat1. After the reaction, the catalyst was easily recovered andreused for four subsequent runs without a significant loss of catalytic activity and no leaching of themetal/ligand was detected during the reaction.