Electrochemical Reduction of CO₂ by the SnS| PTFE| Pt Surface in an Aqueous Imidazole Medium: Catalysis and Kinetics

Development of a novel SnS| PTFE| Pt electrode as an efficient catalyst for electrochemical CO2 reduction to formate in an aqueous alkaline imidazole medium is reported in this paper. The electrode was prepared through the incorporation of polytetrafluoroethylene (PTFE) with SnS and modification of the Pt surface by SnS/PTFE. The electrode facilitated a first-order CO2 reduction at -1.1 V vs Ag/AgCl (saturated KCl) via a diffusion-controlled pathway with a cathodic electron transfer coefficient (alpha) of 0.22 and two-electron transfer kinetics in two steps, where the first electron transfer step determined the reaction rate. The SnS| PTFE| Pt electrode surface exhibited well-defined cyclic voltammograms (CVs) for CO2 reduction in comparison to GCE, Au, Pd, and graphite-modified electrodes utilizing the same catalyst, indicating superior catalytic efficiency and its conduciveness to kinetic investigations. Such performance indicates that the SnS| PTFE| Pt electrode would be a promising alternative for CO2 reduction in the context of renewable energy generation.