FeIr Alloy Optimizes the Trade-Off Between Nitrate Reduction and Active Hydrogen Generation for Efficient Electro-Synthesis of Ammonia in Neutral Media

Electrochemically promoted nitrate reduction reaction (NITRR) holds great potential for the “green” synthesis of ammonia (NH₃). However, NITRR in neutral media, though close to the practical scenario, is often limited by an insufficient supply of active hydrogen (*H) due to sluggish water cleavage. In this work, it is demonstrated that a bimetallic alloy FeIr can optimize the trade-off between nitrate reduction and *H formation in neutral media. As a result, FeIr exhibits excellent catalytic performance toward neutral NITRR with a Faradaic efficiency of NH₃ up to 97.3% and a high yield rate up to 11.67 mg h⁻¹ cm⁻² at a low working potential of −0.6 V (versus reversible hydrogen electrode (RHE)), surpassing the monometallic catalysts as well as the majority of Fe-based state-of-the-art. It is also found that the FeIr displays remarkable electron rearrangement between hetero-atoms due to their significant orbital hybridization, which benefits not only the *H formation but also the NITRR process. Moreover, coupling FeIr-based NITRR with methanol oxidation reaction (MOR) results in sustainable productions of NH₃ and formate with a combined FE of nearly 200% at a cell-voltage of 2 V. This work thus demonstrates a promising strategy for designing efficient catalysts toward neutral NITRR.