Efficient Neutral Nitrate-to-Ammonia Electrosynthesis Using Synergistic Ru-Based Nanoalloys on Nitrogen-Doped Carbon

Electrocatalytic nitrate reduction reaction (NO₃RR) represents a sustainable and environmentally benign route for ammonia (NH₃) synthesis. However, NO₃RR is still limited by the competition from hydrogen evolution reaction (HER) and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates. Here, we report a selective etching strategy to construct RuM nanoalloys (M = Fe, Co, Ni, Cu) uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH₃ electrosynthesis. Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy, significantly lowering the energy barrier for the conversion of *NO₂ to *HNO₂. Experimentally, the optimized RuFe-NC catalyst achieves 100% Faraday efficiency with a high yield rate of 0.83 mg h^-1 mg_cat^-1 at a low potential of - 0.1 V vs. RHE, outperforming most reported catalysts. In situ spectroscopic analyses further demonstrate that the RuM-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals, thereby reducing HER competition. The RuFe-NC assembled Zn-NO₃^- battery achieved a high open-circuit voltage and an outstanding power density and capacity, which drive selective NO₃^- conversion to NH₃. This work provides a powerful synergistic design strategy for efficient NH₃ electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.