Constructing Oxygen Vacancies via Engineering Heterostructured Fe 3 C/Fe 3 O 4 Catalysts for Electrochemical Ammonia Synthesis.

Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions provides an intriguing pathway to convert N ₂ into NH ₃ . However, significant kinetic barriers of the NRR at low temperatures in desirable aqueous electrolytes remain a grand challenge due to the inert N≡N bond of the N ₂ molecule. Herein, we propose a unique strategy for in situ oxygen vacancy construction to address the significant trade-off between N ₂ adsorption and NH ₃ desorption by building a hollow shell structured Fe ₃ C/Fe ₃ O ₄ heterojunction coated with carbon frameworks (Fe ₃ C/Fe ₃ O ₄ @C). In the heterostructure, the Fe ₃ C triggers the oxygen vacancies of the Fe ₃ O ₄ component, which are likely active sites for the NRR. The design could optimize the adsorption strength of the N ₂ and N _x H _y intermediates, thus boosting the catalytic activity for the NRR. This work highlights the significance of the interaction between defect and interface engineering for regulating electrocatalytic properties of heterostructured catalysts for the challenging NRR. It could motivate an in-depth exploration to advance N ₂ reduction to ammonia.
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