Converting greenhouse gas carbon dioxide (CO2) to value-added chemicals is an appealing approach to tackle CO2 emission challenges. The chemical transformation of CO2 requires suitable catalysts that can lower the activation energy barrier to minimize the energy penalty associated with the CO2 reduction reaction. To probe the electrode/electrolyte interface and elucidate the reaction mechanism, we recently studied the electrochemical CO2 reduction on Au catalyst using operando surface enhanced infrared absorption spectroscopy (SEIRAS).[1] The newly developed operando ATR-SEIRAS technique allowed us to show that bicarbonate, through equilibrium exchange with dissolved CO2, rather than the supplied CO2, is involved in the CO formed at the Au electrode, which cannot be observed using traditional ex-situ vibrational spectroscopic techniques. We will also discuss recent advances in reaction mechanism studies in electrochemical CO2 reduction. We will also present our work in developing an integrated two-stage electrolyzer stack system for the conversion of CO2 to alcohols. The first stage utilizes a state-of- the art nanoporous Ag catalyst in a flow cell capable of reducing CO2 to CO with faradaic efficiencies of &gt;95% and partial current densities of 40 mA/cm2 with facile separation of the CO product. For the second stage, a CO reduction flow cell using alkaline electrolyte can reduce CO to C2+ products with high selectivity (80%) and high current density (&gt;500 mA/cm2). This work demonstrates the feasible production of multi-carbon alcohols via CO reduction at appreciable rates, and motivates further development of a two-stage electroreduction process of CO2 to alcohols.

Electrochemical CO2 conversion to valuable chemicals

256th National Meeting (2018)

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