Economically viable electrocatalytic ethylene production with high yield and selectivity

Electrocatalytic semihydrogenation of acetylene provides a clean pathway to the production of ethylene (C2H4), one of the most widely used petrochemical feedstocks. However, its performance is still well below that of the thermocatalytic route, leaving the practical feasibility of this electrochemical process questionable. Here our techno-economic analysis shows that this process becomes profitable if the Faraday efficiency exceeds 85% at a current density of 0.2 A cm−2. As a result, we design a Cu nanoparticle catalyst with coordinatively unsaturated sites to steer the reaction towards these targets. Our electrocatalyst synthesized on gas diffusion layer coated carbon paper enables a high C2H4 yield rate of 70.15 mmol mg−1 h−1 and a Faraday efficiency of 97.7% at an industrially relevant current density of 0.5 A cm−2. Combined characterizations and calculations reveal that this performance can be attributed to the favourable combination of a higher energy barrier for the coupling of active hydrogen atoms (H*) and weak absorption of *C2H4. The former suppresses the competitive hydrogen evolution reaction, whereas the latter avoids overhydrogenation and C–C coupling. Further life cycle assessment evidences the economic feasibility and sustainability of the process. Our work suggests a way towards rational design and manipulation of nanocatalysts that could find wider and greener catalytic applications.