Experimental Investigation of Cost-Effective Electrochemical Reduction of Carbon Dioxide to Formic Acid as a Potential Fuel

Electrochemical reduction of carbon dioxide to feedstocks, such as formic acid, which is considered a potential liquid fuel for various systems, including fuel cells, is a promising technology for reducing anthropogenic carbon emissions and combating climate change. Copper mesh is selected as the support to provide a uniform structure that enables uniform tin electrodeposition, thereby improving reproducibility, which is more difficult to achieve with other support materials, such as copper foams. Moreover, copper mesh is a relatively low-cost material that could help reduce the cost of CO 2 RR. This study investigates the effect of tin deposition duration on the performance of copper mesh catalysts in the electroreduction of carbon dioxide. The electrocatalyst electrodeposition durations are 2, 5, 10, and 20 minutes, and the synthesized catalysts are designated as Sn2, Sn5, Sn10, and Sn20, respectively. The electrochemical reduction is performed in a two-compartment H-type cell using a three-electrode system, applying -1.0 V vs. RHE (-1.7 V vs. Ag/AgCl) for 60 minutes in a CO 2 -saturated 0.5 M KHCO 3 solution. The obtained electrocatalyst, a graphite rod and Ag/AgCl 3 M KCl electrodes are used as the working, counter and reference electrodes, respectively. The highest apparent Faradaic efficiency for formic acid production is found to be 51.92% with a current density of 71.5 mA cm −2 and the formic acid production rate per unit electrode area reaches 693 µmol h −1 cm −2 . The highest performance during carbon dioxide electroreduction is achieved with the Sn10 electrode, indicating that electrocatalytic activity strongly correlates with the morphology and structure of the catalysts.