Single catalyst electrocatalytic reduction of CO2 in water to H-2+CO syngas mixtures with water oxidation to O-2

A single Ru(II) polypyridyl carbene complex catalyzes the electrochemical reduction of CO2 in water with added bicarbonate to give syngas H-2+CO mixtures at the cathode and water oxidation to O-2 at the anode. The H-2/CO ratio in the syngas product can be adjusted between 4 : 1 and 1 : 2 by varying the applied potential and solution pH with overall electrolysis energy efficiencies near 50%.