Sol-Gel Synthesis of CuO Nanoparticles and Its Use as Catalyst for Electrochemical CO2 Reduction

Copper and copper-based catalysts have been recognized as attractive heterogeneous catalysts for electrochemical CO2 reduction. Herein, the synthesis of copper oxide (CuO) nanoparticles via a sol-gel process using agar as the dispersant agent followed by thermal annealing at 400, 600, and 800 degrees C is reported on. Evolution of chemical composition, morphology, and crystallinity of CuO nanoparticles in function the annealing temperature is examined. These CuO nanoparticles are assayed as catalysts for the CO2 electrochemical reduction in a 0.1 m NaHCO3 or 0.1 m KHCO3 solution saturated with CO2, generating hydrogen, carbon monoxide, formate, and acetate as products. Among the CuO catalysts assayed, the CuO-400 sample obtained at the annealing temperature of 400 degrees C leads to the highest formate production selectivity with a Faradaic efficiency of 26% at -0.9 V versus reversible hydrogen electrode.