Enhanced electrochemical conversion of CO2 into formic acid using PbSO4/AtSn electrode: Catalyst synthesis and process optimization

Abstract

Electrochemical carbon dioxide (CO2) reduction is among the most promising and effective methods for producing valuable fuels while simultaneously addressing global warming. Numerous metal-based materials showed promising potential for CO2 conversion due to their distinct physical, mechanical, and electrical capabilities. However, there is often a continuous challenge to fabricating stable electrode systems with high Faradaic efficiency %. In this study, an electrochemical catalyst consisting of lead sulphate was synthesized, deposited on acid treated tin foil (PbSO4/AtSn) and tested for the CO2 ECR. The prepared Pb-based catalyst demonstrated a high faradaic efficiency of 79.8% at − 26 mA in a 0.11 M CO2-saturated NaHCO3 aqueous solution, which was significantly higher than both the acid treated and untreated blank Sn foil. The catalyst also exhibited lower energy consumption (0.0695 kWh.mol−1) compared to the most commonly used formic acid-producing electrocatalyst. At a constant current of − 26 mA, the catalyst continued to function after 20 h of continuous CO2 electrochemical reduction. Experimental design was used to optimize the fabricated catalyst performance at different operating conditions. Optimum performance was obtained at − 26 mA current, 0.11 M electrolyte concentration, and 1.42 mg of catalyst to obtain the highest faradic efficiency. According to the experimental findings, the Pb-based catalyst's superior catalytic performance could be attributed to its larger electrochemical active surface area and reduced charge-transfer resistance. These promising results suggest that the prepared Pb-based catalyst can be highly effective for electrochemical reduction of CO2 with promising potential for commercialization.