Electrochemical reduction of CO2 to HCOOH on a synthesized Sn electrocatalyst using a Co3O4 anode

Abstract

The present work investigates the electrocatalytic effect of tin (Sn) and cobalt oxide (Co₃O₄) on the reduction of CO₂ to products electrochemically (RCPE). Electrocatalytic (Sn) powder was synthesized by an electrodeposition method from a SnCl₂·2H₂O solution. Experiments were conducted using Co₃O₄ and Sn electrodes as the anode and cathode, respectively, in 0.5 M potassium and sodium carbonate and bicarbonate solutions. The electrodes were prepared by coating the electrocatalysts onto a graphite plate surface. The experiments were conducted with different applied voltages (1.5 to 3.5 V) and time intervals (5, 10, 15, 20 and 25 min) in the various electrolyte solutions. It was observed that HCOOH acid was the only product formed for all the applied conditions. At 1.5 V and 2 V, maximum Faradaic efficiencies of 74.04% and 92.6% for HCOOH production were obtained from 20 and 5 min reactions in a KHCO₃ electrolyte solution. The ability of Co₃O₄ to perform water oxidation and the Sn electrocatalyst to reduce CO₂ to HCOOH was established from the obtained results. The optimized reaction conditions to achieve high Faradaic efficiencies are explained in detail.