Coupling CO2-to-Ethylene Reduction with the Chlor-Alkaline Process in Seawater through In Situ-Formed Cu Catalysts

The overall commercial value of a CO2 electroreduction system is hindered by the valueless product and high energy consumption of the oxygen evolution reaction (OER) at the anode. Herein, with an in situ-formed copper catalyst, we employed the alternative chlorine evolution reaction for OER, and high-speed formation of both C2 products and hypochlorite in seawater can be realized. The EDTA in the sea salt electrolyte can trigger an intense dissolution and deposition of Cu on the surface of the electrode, resulting in the in situ formation of dendrites of Cu with high chemical activity. In this system, a faradaic efficiency of 47% can be realized for C2H4 production at the cathode and a faradaic efficiency of 85% can be realized for hypochlorite production at the anode with an operation current of 100 mA/cm2. This work presents a system for designing a highly efficient coupling system for the CO2 reduction reaction and alternative anodic reactions toward value-added products in a seawater environment.