CeO2-promoted Cu2O-based catalyst sprayed on the gas diffusion layer for the electroreduction of carbon dioxide to ethylene

Abstract

The development of efficient and selective catalysts for the carbon dioxide reduction reaction (CO₂RR) is crucial for sustainable energy and chemical synthesis. In this work, CeO_2-y (y = C (cubic) and R (rod)) was incorporated into Cu₂O nanocube electrocatalyst as a promoter for ethylene (C₂H₄) production. The results demonstrate that the catalyst with a loading of 5 wt% crystalline CeO_2-C exhibits competitive activity and stability for ethylene production compared to pristine Cu₂O. Under optimized reaction conditions of −250 mA cm⁻² current density and 1 M KOH electrolyte, the Cu₂O–5CeO_2-C catalyst achieved a faradaic efficiency (FE) of ∼53% for C₂H₄ production, while maintaining stability over a period of 120 minutes. In contrast, non-promoted Cu₂O exhibited a lower FE for C₂H₄ (∼38%) and experienced partial deactivation after 45 minutes. The characterization of the catalysts before and after the reaction revealed that the interaction between Cu₂O and CeO_2-C creates intrinsic sites (Cu^x–CeO_2−x; Cu^x = Cu²⁺, Cu⁺, and Cu⁰) for the binding of CO₂ and H₂O molecules. Moreover, the Cu₂O–5CeO_2-C catalyst outperforms other reported systems in terms of FE and partial current density for C₂H₄ production. It requires a lower potential (−0.98 V vs. RHE) to operate at the same electrolyte concentration. This finding highlights the promising nature of Cu₂O–5CeO_2-C as an efficient and cost-effective catalyst for C₂H₄ production.