Mo/NiCu Heterometallic Interfaces for the Selective Electrosynthesis of Nitrite from Ammonia

The electrochemical ammonia oxidation reaction (AOR) holds great promise due to its potentially low energy consumption and the production of high-value nitrites. However, achieving high efficiency and selectivity in the conversion of ammonia to nitrites remains a significant challenge owing to the diversity and competitiveness of reaction pathways. In this work, a NiCu-loaded Mo catalyst (denoted as Mo/NiCu) was synthesized via a simple hydrothermal method followed by high-temperature reduction. Comprehensive characterization and theoretical investigations reveal that the interfacial electronic interaction between Mo and the NiCu alloys effectively modulate the Fermi level of the NiCu catalyst, thereby enhancing ammonia adsorption and promoting the ammonia oxidation reaction. Electrocatalytic performance tests in a flow cell configuration demonstrate that the catalyst achieves 98% nitrite selectivity at 1.9 V and maintains stable operation for over 60 h. This study provides a new strategy for designing efficient, stable, and cost-effective AOR catalysts, thereby facilitating the practical application of electrocatalytic nitrite synthesis.