During the past few decades, the increasing atmospheric CO2 levels have led to a number of undesired climate effects. The electrochemical reduction of CO2 to value-added products such as CO, methane, formic acid, ethanol and ethylene is one of several approaches that may help reduce CO2 emission and eventually curb the effects of climate change.[1, 2] Such electrochemical processes also have the potential for utilizing otherwise wasted excess solar or wind energy, produced when the supply from these intermittent sources exceeds the demand of the grid.
Among the possible products from this process, hydrocarbons such as ethylene and ethanol are preferred over CO because they are either important industrial raw materials or high energy-density fuels. Cu is the only known catalyst that produces considerable amounts of hydrocarbons. However, the overpotential of Cu for hydrocarbon production is usually above 0.7 V. Here, we will present our work on the synthesis and application of Cu nanoparticles as active cathode catalysts for the efficient conversion of CO2 to ethylene and ethanol. With the use of an active anode catalyst (IrO2) and optimized operation conditions in an electrochemical flow cell, the cathode catalyst presented here has achieved much lower overpotential and higher partial current densities for ethylene and ethanol than most reported work. This paper will also cover some of the determining factors that affect product distribution.
 D.T. Whipple, P.J.A. Kenis, J. Phys. Chem. Lett., 1 (2010) 3451-3458.
 H.-R.M. Jhong, S. Ma, P.J.A. Kenis, Curr. Opin. Chem. Eng., 2 (2013) 191-199.
 S. Ma, R. Luo, S. Moniri, Y. Lan, P.J.A. Kenis, J. Electrochem. Soc., 161 (2014) F1124-F1131.
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