Efficient Ammonia Electrosynthesis from Nitrate on Non-Noble Fe/CeO₂ Catalyst

Ammonia (NH₃) can be used as a fertilizer, a chemical or a new generation of fuel and has important agricultural and industrial value. Electrochemical NO₃^–-to-NH₃ (NITRR) can realize the conversion of waste into treasure and waste resources, which is a promising method for ammonia synthesis. However, the process of NITRR is very complicated, resulting in product diversification and poor selectivity. In this work, an iron modified cerium oxide in rod form (Fe/CeO₂-rod) catalysts was designed and used for the NITRR. The Fe/CeO₂-rod catalyst showed excellent activity, and achieves high Faradaic efficiency (FE 95%) and NH₃ yield rate (4.04 mg h^–1 cm^–2) in 0.1 M KOH electrolyte at – 0.52 V versus reversible hydrogen electrode. Furthermore, this catalyst exhibits a negligible activity decay during continuous electrolysis for 25 h. Further experiments provide the important role of Fe, which promote the formation of hydrogen radicals (H*). This study may provide new pathways to improve the activity of inexpensive catalysts for NITRR.