Interfacial Engineering to Fabricate Nanoporous FeMo Bimetallic Nitride for Enhanced Electrochemical Ammonia Synthesis

Abstract

The electrochemical N₂ reduction reaction (NRR) currently represents a green and sustainable approach to ammonia production. However, the further progress of NRR is significantly hampered by poor catalytic activity and selectivity, necessitating the development of efficient and stable electrocatalysts. Herein, a nanoporous Fe–Mo bimetallic nitride (Fe₃N-MoN) is synthesized using a molten-salt preparation method. This catalyst demonstrates notable NRR performance, achieving a high NH₃ yield rate of 45.1 µg h⁻¹ mg⁻¹ and a Faradaic efficiency (FE) of 26.5% at −0.2 V (vs RHE) under ambient conditions. Detailed experimental studies and density functional theory (DFT) calculations reveal that the fabricated interface between Fe₃N and MoN effectively modulates the surface electronic structure of the catalyst. The interface induces an increase in the degree of electron deficiency at the nitrogen-vacancy sites on the catalyst surface, allowing N₂ molecules to occupy the nitrogen vacancies more easily, thereby promoting N₂ adsorption/activation during the NRR process. Consequently, the Fe₃N-MoN catalyst exhibits outstanding NRR activity. The insights gained from fabricating the Fe₃N-MoN interface in this work pave the way for further development of interfacial engineering to prepare high-efficient electrocatalyst.