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 Cu2 O-CeO2 -C nanorods are prepared on copper mesh through a metal-organic framework template route. The Cu-loaded Ce-MOF is thermally converted to Cu2 O-CeO2 heterojunctions with interfacial Cu-[OX ]-Ce structures embedded in carbon. Theoretical calculations reveal the lower formation energy of oxygen vacancies in Cu-[OX ]-Ce structures than in the Cu2 O or CeO2 phase. The Cu-[OX ]-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 NH3 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.
Keywords: CeO 2; Cu 2O; electrocatalysis; metal-organic frameworks; nitrogen reduction.
© 2022 Wiley-VCH GmbH.