CO2 Electrochemical Reduction to Hydrocarbon Fuels on Carbon-Supported Copper Nanoparticles: Support Effect
Cu nanoparticles of 15-25 nm diameters on different carbon supports were synthesized by the reduction of CuCl2 using NaBH4 in aqueous ethylene glycol solution (20% v/v). X-Ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) were used for nanoparticles ex-situ analysis. The catalytic activities and selectivity of supported Cu nanoparticles towards CO2 electrochemical reduction to hydrocarbon fuels were evaluated using a sealed rotating disk electrode (RDE) setup connected to a gas chromatograph1.
Cu nanoparticles supported on VC and OLC exhibited higher catalytic activity vs other catalysts towards CH4 and C2H4 generation, respectively, between -1.4 and -1.6 V (vs Ag/AgCl reference electrode). At a more negative potential of -1.6 V, all five Cu catalysts promoted generation of both CH4 and C2H4, with the higher selectivity in terms of Faradaic efficiencies towards C2H4 formation. The C2H4/CH4 ratio increased by almost an order of magnitude in the following order: Cu/VC (2.6:1) <Cu/KB (4.5:1) < Cu/SWNT (5.8:1) < Cu/GPO (10.8:1)< Cu/OLC (33:1). Cu/OLC showed both the lowest onset potential and the greatest selectivity towards C2H4 formation.
This presentation will discuss the reasoning behind the different catalytic activity and selectivity of supported Cu nanoparticles in catalyzing the CO2 electrochemical reduction reaction.
 O. A. Baturina, Q. Lu, M. A. Padilla, L. Xin, W. Li, A. Serov, K. Artyushkova, P. Atanassov, F. Xu, A. Epshteyn, T. Brintlinger, M. Schuette, and G. E. Collins, ACS Catal. 2014, 4, 3682.
 P. V. Kamat, J. Phys. Chem. Lett. 1 (2010), 520.
 J. K. McDonoug, Y Gogotsi, Interface, 22 (2013), 61.