Electrochemical Performance of Electrodeposited Sn-Based Catalyst for Reduction of CO2 to Formic Acid

Abstract Formic acid is a valuable chemical for various industries and is utilised in low-temperature direct formic acid fuel cells due to their high energy density. Although metals such as lead, bismuth, mercury, and cadmium are widely used as potential catalysts for converting CO2 into formic acid, their toxicity and environmental impact limit their large-scale application. This study, conducted as part of the REUSE project (HORIZON EUROPE), focuses on tin (Sn)-based catalysts due to their low toxicity, high catalytic activity, and good selectivity. However, maintaining long-term stability under industrially relevant conditions is a significant challenge. We examine the stability of shape-controlled Sn catalysts electrodeposited on carbon paper via halide-free, environmentally responsible routes, which have a microporous layer composed of multi-walled carbon nanotubes. Electrochemical techniques, including Linear Sweep Voltammetry (LSV), Electrochemical Impedance Spectroscopy (EIS), and Chronoamperometry (CA), were employed to assess the performance of the Sn-based catalyst in 0.1M KHCO3. The Sn-based electrodes demonstrated excellent stability, providing promising insights into the scalable utilisation of CO2 with non-precious materials for sustainable formic acid production.