20% Efficient Solar CO2 Electrolysis with Earth-Abundant Materials Enabled by Molecular Catalyst

Solar-driven CO2 conversion combining photovoltaics (PV) and electrochemical systems (EC) could potentially allow the carbon-neutral synthesis of fuels and chemicals. However, present-day PV+EC systems have practical limitations related to the high overvoltage and the use of precious metal catalysts in EC. These challenges result in expensive PV with high voltages. Molecular metal complex catalysts can permit lower overvoltages and the use of Earth-Abundant metals. The work reported herein loaded a Mn(I) complex polymer in a gas diffusion flow reactor and demonstrated the electrochemical conversion of CO2 to CO with 94% selectivity at a cell voltage of 1.35 V. This Earth-Abundant CO2 electrolyzer combined with inexpensive silicon PV achieved solar-to-CO conversion efficiency of 20%, which suggests the possible realization of an artificial sustainable carbon cycle.