Reduction of carbon dioxide into formic acid using transition metal complexes as catalysts is a research area of abiding importance. Although ruthenium(II) complexes as ‘molecular catalysts’ have received much attention, use of ruthenium(III) complexes in the selective reduction of carbon dioxide into formic acid has recently been explored. This review focuses on the recent research progress in the use of a ruthenium(III) complex containing the ‘edta’ ligand (edta4- = ethylenediaminetetraacetate) as catalyst or mediator in the catalytic, electro-catalytic and photocatalytic conversion of bicarbonate to formate selectively. Details of the reaction mechanism pertaining to the overall catalytic process are discussed.
Keywords: Ruthenium(III) complex, bicarbonate, reduction, catalysis, electro-catalysis, photo-catalysis, formate.