Selective Conversion of CO_2 to CO with High Efficiency Using an Inexpensive Bismuth-Based Electrocatalyst

摘要

The wide-scale implementation of solar and other renewable sources of electricity requires improved means for energy storage. An intriguing strategy in this regard is the reduction of CO_2 to CO, which generates an energy-rich commodity chemical that can be coupled to liquid fuel production. In this work, we report an inexpensive bismuth-carbon monoxide evolving catalyst (Bi-CMEC) that can be formed upon cathodic polarization of an inert glassy carbon electrode in acidic solutions containing Bi~(3+) ions. This catalyst can be used in conjunction with ionic liquids to effect the electrocatalytic conversion of CO_2 to CO with appreciable current density at overpotentials below 0.2 V. Bi-CMEC is selective for production of CO, operating with a Faradaic efficiency of approximately 95%. When taken together, these correspond to a high-energy efficiency for CO production, on par with that which has historically only been observed using expensive silver and gold cathodes.