Boosting ammonia production in electrocatalytic NO_x reduction on a robust Fe/FeMoO₄ catalyst

Electrocatalytic reduction of nitrate (NO3-) and nitride (NO2-) to ammonia (NH3) is of wide interest as a promising alternative to the energy-intensive Haber-Bosch route for mitigating the vast energy consumption and the accompanied carbon dioxide emission, as well as benefiting for the relevant sewage treatment. However, exploring an efficient and low-cost catalyst with high atomic utilization that can effectively facilitate the slow multi-electron transfer process remains a grand challenge. Herein, we present an efficient hydrogenation of NO3-/NO2- species to NH3 in both alkaline and neutral environments over the Fe-2(MoO4)(3) derived hybrid electrocatalyst with the metallic Fe site on FeMoO4 (Fe/FeMoO4). The Mo ingredient can play a synergistically positive role in further promoting the NH3 production on Fe. As a result, Fe/FeMoO4 behaves well in the electrochemical NH3 generation from NO2- with a maximum NH3 Faradaic efficiency (FE) of 96.53% and 87.68% in alkaline and neutral electrolyte, corresponding to the NH3 yield rate of 640.68 and 302.56 mg & sdot;h(-1)& sdot;mg(cat.)(-1), respectively, which outperforms the Fe and Mo counterpart and other similar catalyst, showing the robust catalytic capacity of each active site.