Efficient Ethane Production via SnCl4 Lewis Acid-Enhanced CO2 Electroreduction in a Flow Cell Electrolyser

The development of efficient and selective catalysts for electrochemical CO2 reduction (CO2RR) is critical for advancing sustainable energy solutions. Here, we report a unique catalyst system based on SnCl4 Lewis acid-modified Cu2O, demonstrating enhanced performance in CO2 electroreduction to ethane. The SnCl4 modification introduces chloride ions directly onto the Cu2O surface, creating a synergistic interaction between Sn, Cl, and Cu active sites that optimizes the electronic environment for CO2RR. The catalyst was coated onto a gas diffusion electrode (GDE) and tested in a flow cell electrolyser, with a Fumasep bipolar membrane and a platinum (Pt) foil as the anode. This system achieved a peak Faradaic efficiency of 34.8% for ethane production at -1.0 V vs. RHE, along with 11.3% efficiency for ethylene. Electrochemical studies revealed that the SnCl4-modified Cu2O exhibits low charge transfer resistance and high stability during prolonged electrolysis, with total current densities reaching 74.8 mA cm-2 with a Tafel slope of 92.3 mV/dec at 0.4 V overpotential. Mechanistic investigations, supported by density functional theory, Raman, XRD, and electrochemical Impedance spectroscopy analyses, highlight the critical role of chloride ions in stabilizing CO intermediates and facilitating C-C bond formation, essential for C2 product generation. Operating in a flow cell configuration, the system demonstrated high energy efficiency and selectivity, establishing the SnCl4-modified Cu2O (CTC) as a promising catalyst for CO2RR. These findings offer a scalable and economically viable pathway for renewable hydrocarbon production, paving the way for practical applications in carbon-neutral energy cycles.