Tuesday, November 10, 2015: 10:30 AM
355D (Salt Palace Convention Center)
Electrochemical reduction of CO2, an artificial way of carbon recycling, represents one promising solution for energy and environment sustainability. Despite the many advantages, electrochemical reduction of CO2 is challenged by the absence of efficient catalysts for this reaction. Copper (Cu) is the most studied material capable of catalyzing CO2 reduction at significant rates, but it still requires large overpotentials; e.g., to reach a current density of 1 mA/cm2 on polycrystalline Cu electrode, it typically requires an overpotential of >0.5 V for producing CO and HCOOH (two-electro processes) and >0.8 V for further reduced products such as CH4 and C2H4. Moreover, hydrogen evolution competes with CO2 reduction, reducing the Faradaic efficiency (FE) towards carbon-containing compounds. Here we report the synthesis of highly dense Cu nanowires and their superior performance for electrocatalytic CO2 reduction. CuO nanowires were first grown thermal treatment of Cu gauze in air, which were then subjected to electrochemical reduction or annealing in a reducing atmosphere to form Cu nanowires . The obtained Cu nanowires were then applied as electrocatalysts for CO2 reduction. These nanowires were found to be highly active at the low-overpotential regions, i.e., E ≤ 0.5 V, and also possess high selectivity for CO2 reduction. The electrocatalytic performance was further found to depend on the nanostructures of the nanowires that gave rise to surface sites catalyzing CO2 reduction efficiently.