Electrochemical Reduction of CO2 Using Supported Cu2O Nanoparticles

We have studied the electrochemical reduction of CO 2 using Cu 2 O catalysts prepared by nanoparticle synthesis (i.e., chemical reduction) and by electrochemical deposition. Both preparation methods give catalysts that exhibit high formation rates for CO and C 2 H 4 relative to CH 4 , compared to Cu foil electrodes. The main difference is a higher relative rate of CO formation using the nanoparticle catalysts. Highly loaded nanoparticle catalysts give the highest overall rates for CO 2 product formation, most likely because of their greater surface area. Lower loaded catalysts show evidence that product selectivity is affected by the competing H 2 reaction on the carbon fiber support. Characterization using SEM and XRD together with transient current behavior suggests that Cu 2 O is reduced in two stages, with the initial formation of dispersed Cu clusters occurring rapidly on the oxide surface, followed by a much slower reduction of the interior of the oxide.