Engineered Electrolyte-Electrocatalyst Nanocomposites for Enhanced CO2 Electroreduction

Abstract

The development of a viable approach to capture, store, and convert carbon dioxide into fuels and chemicals may offer a means to mitigate climate change while also creating value added commodity chemicals. Critical bottlenecks in existing technologies that have impeded commercialization of CO2 electrosynthesis include catalysts with high overpotentials and limited selectivities. Furthermore, current approaches often employ PEM-based electrolyzers that suffer from low CO2 solubility in acidic aqueous solutions, limiting mass transport and reaction rates, or AEM-based systems which have much higher CO2 solubilites in alkaline electrolytes, but have the added problem of membrane poisoning by bicarbonate and carbonate.We have recently developed an electrochemical reactor that overcomes many of the shortcomings that have limited the above technologies. Our preliminary results suggest that onset potentials for CO2 reduction are more than 200 mV lower than with current densities in excess of 150 mA/cm2 at -1 V vs RHE. The selectivities for CO are in excess of 90% and the electrocatalysts. We have examined several cathode electrocatalysts and some of the most promising include a series of nanostructured mixed and/or doped transition metal and main group metal oxides that also suppress the hydrogen evolution reaction. We will present detailed electrochemical and structural studies and will comment on possible reaction mechanisms as well as the key features of the reactor that enable the enhanced kinetics.