CO2 electroreduction using Cu supported Co3O4 catalyst for multi-electron product formation via metal support interaction

Abstract

In this work, we have utilized the concept of metal support interaction to develop an electrocatalyst based on copper/copper oxide. Cobalt oxide was selected as the oxide support, synthesized by the solution combustion method, upon which copper nanoparticles were dispersed using the formaldehyde reduction method. Different concentrations of Cu (1, 2.5, 5, 10 and 15 %) were loaded over the support, amongst which the 2.5% Cu/Co3O4 system worked best by giving a Faradaic efficiency of 34%. Detailed catalyst characterisations were performed using XRD, FESEM, ICP-OES, HRTEM, EDX, and XPS analysis. Electrochemical studies were carried out to estimate the catalyst’s activity using techniques such as cyclic voltammetry and chronoamperometry. High-value gaseous (CO, CH4) and liquid products (CH3CH(OH)CH3) were identified during the CO2 electroreduction process. Liquid IPA (Isopropyl alcohol) forms at a very low over-voltage (~200 mV). Pre- and post-reaction XRD showed slight shifting of peaks. In XPS, pre- and post-spectra reveal complete and partial oxidation of Cu+2/Cu+ and Co3O4 respectively. Electrocatalytic activity of the catalyst was also compared with its precursors (Cu and Co3O4), and the activity of these precursors was much less compared to Cu/Co3O4 system due to metal-support interaction.