Cavity-confined Cu2O nanoreactors for efficient CO2 electroreduction to ethylene

Abstract

Electrocatalytic carbon dioxide reduction (eCO₂R) to ethylene (C₂H₄) offers a promising pathway toward carbon–neutral cycles and sustainable chemical synthesis. In eCO₂R to C₂H₄, copper-based electrocatalysts, particularly Cu₂O, have been widely used. Nevertheless, product selectivity to C₂H₄ is still quite limited due to the insufficient enrichment of key intermediates and slow C–C coupling kinetics. Herein, the double-shelled hollow mesoporous Cu₂O was fabricated through the soft-templating method. And the cavity size and pore architecture of the resulting Cu₂O catalysts could be precisely tailored by adjusting the alkyl chain length of the surfactant templates alkyltrimethylammonium bromides. When applied to eCO₂R, the as-prepared Cu₂O material with tetradecyltrimethylammonium bromide (TTAB) as template exhibited a remarkable Faradaic efficiency of 43.3 ± 0.8% for C₂H₄ at an industrial-level current density of 549.8 mA cm⁻². Experimental and theoretical investigations reveal that its high activity and selectivity toward C₂H₄ stem from the suitable cavity configuration, which enriches key *CO intermediates and promotes their dimerization via a spatial confinement effect. This study provides valuable insights into the architectural design of efficient catalysts for CO₂-to-C₂H₄ conversion.