Electrified Acetylene Removal From Ethylene Streams Enabled by Facet-Engineered Cu-TiO₂ Interfaces

Removal of trace acetylene from ethylene is essential for polymer-grade olefin production, yet current thermocatalytic purification requires elevated temperatures and hydrogen input. Here we report an electrified route for acetylene removal from ethylene streams using facet-engineered Cu-TiO₂ interfaces. By tuning the exposed facets of anatase TiO₂, we regulate the interfacial electronic interaction with supported Cu nanoclusters and thereby the balance among acetylene hydrogenation, hydrogen evolution, and carbon-carbon coupling. Among the catalysts examined, Cu-TiO₂ {001} provides the most effective interfacial environment for selective acetylene-to-ethylene conversion, delivering an ethylene Faradaic efficiency (FE) of 95.4% under acetylene-rich feed. Under purification-relevant acetylene-lean conditions, a 25 cm² flow electrode suppresses residual acetylene to below 5 ppm while maintaining H₂ FE below 5% during prolonged operation. Combined spectroscopy and theory indicate that the {001} facet strengthens Cu-TiO₂ electronic coupling, stabilizes the Cu electronic structure and key hydrogenation intermediates under operating conditions, and disfavors competing pathways. Techno-economic analysis supports the process potential of this electrified purification strategy.