Electrochemical reduction of CO2 to Formic Acid on Pb-Sn Alloy Cathode

Authors: Pramujo Widiatmoko¹, Isdiriayani Nurdin¹, Hary Devianto¹, Budi Prakarsa¹ and Henry Hudoyo¹

Carbon dioxide released to the atmosphere due to fossil combustion needs to be reduced to decrease the global warming effect. Electrochemical reduction of CO₂ is one of promising technology to convert CO₂ to various valuable compounds, reducing the amount of released CO₂ to the atmosphere. Metal alloys are interesting material for cathode. In this preliminary work, a CO₂ electrochemical reduction was performed on a Pb-Sn alloy cathode using catholyte of KHCO₃ and NaHCO₃ at various concentrations. An anode from Pt-Ir and H₂SO₄ 0.1 M as anolyte were used in the experiment. The CO₂ was bubbled into 400 mL catholyte at rate of 75 mL min^-1. It was found that Pb-Sn alloy in KHCO₃ electrolyte provides higher productivity and faradaic efficiency than in NaHCO₃. Increasing overpotential from 0.1 V to 1 V increases both formic acid productivity and efficiency. The optimum amount of formic acid produced was 9400 μmol in catholyte KHCO₃ 0.5 M with faradaic efficiency of 67.19% and conversion of 0.326%.