Electrochemical reduction of CO2, an artificial way of carbon recycling, represents one promising solution for energy and environmental sustainability. Despite the many advantages, electrochemical reduction of CO2 is challenged by the absence of efficient catalysts for this reaction. Copper (Cu) is one of the most studied material capable of catalyzing CO2 reduction at significant rates and producing (oxygenated) hydrocarbons, but the existing Cu catalysts still requires large overpotentials. Moreover, hydrogen evolution competes with CO2 reduction, reducing the selectivity toward carbon-containing compounds. This presentation will discuss our recent progress on the synthesis of highly dense Cu nanowires and tailoring of their surface structures to achieve superior performance for electrocatalytic CO2 and CO reduction, with particular interest in low-overpotential conditions. CuO nanowires were first grown by oxidizing Cu mesh in air which were then subjected to electrochemical reduction or annealing in a reducing atmosphere to form Cu nanowires. By tailoring the conditions for the reduction, high activity and selectivity were achieved for the production of CO from CO2, and ethanol, acetate or methanol from CO reduction at low overpotentials (e.g., less than 0.5 V). It was found that the catalytic performance of the Cu nanowires is strongly correlated to the crystalline and surface structures of the nanowires, based on which the active sites capable of selective reduction of CO2 and CO were identified. Our work indicates the great potential of using electrochemical conversion to produce fuel molecules and chemical feedstocks from carbon dioxide, a greenhouse gas emitted by burning fossil fuels.

Low-overpotential electrochemical reduction of CO2 and CO enabled by Cu nanowires

251st National Meeting (2016)

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