Formation of Interfacial Cu‐[OX]‐Ce Structures with Oxygen Vacancies for Enhanced Electrocatalytic Nitrogen Reduction

Abstract Electrochemical nitrogen reduction powered by renewable electricity is a promising strategy to produce ammonia. However, the lack of efficient yet cheap electrocatalysts remains the biggest challenge. Herein, hybrid Cu 2 O‐CeO 2 ‐C nanorods are prepared on copper mesh through a metal‐organic framework template route. The Cu‐loaded Ce‐MOF is thermally converted to Cu 2 O‐CeO 2 heterojunctions with interfacial Cu‐[O X ]‐Ce structures embedded in carbon. Theoretical calculations reveal the lower formation energy of oxygen vacancies in Cu‐[O X ]‐Ce structures than in the Cu 2 O or CeO 2 phase. The Cu‐[O X ]‐Ce structures with oxygen vacancies enable the formation of interfacial electron‐rich Cu(I) species which show significantly enhanced performance toward electrocatalytic nitrogen reduction with an NH 3 yield of 6.37 × 10 −3 µg s −1 cm −2 and a Faradaic efficiency of 18.21% in 0.10 m KOH at −0.3 V versus reversible hydrogen electrode. This work highlights the importance of modulation of charge distribution of Cu‐based electrocatalysts to boost the activity toward nitrogen reduction.