Electrocatalytic nitrate reduction to ammonia: A perspective on Fe/Cu-containing catalysts

Electrocatalytic reduction reaction of nitrate (NO3RR) to ammonia is becoming ever more pivotal for the sustainable production of NH3, alleviating the nitrate pollution and even for rebalancing the nitrogen cycle globally. Considerable efforts have been devoted to the rational development of catalyst systems in electrocatalytic NO3RR to NH3, and Fe/Cu-containing catalysts have shown significant advantages and are currently in the spotlight which have addressed remarkable attention and academic interest. In this Perspective, we first briefly discuss the possible reaction pathways of electrocatalytic NO3RR to NH3. Emphasis is put on the three catalyst approaches for enhancing the NO3RR performance, based on the selected case studies of the most representative Fe/Cu-containing catalysts. Furthermore, this Perspective assesses the recent progress on the utility and application of the state-of-the-art in situ characterization technologies applied in recent showcases of electrocatalytic NO3RR to NH3, with a special focus on spectroscopies. Finally, the open challenges and outlook regarding the rational design of efficient electrocatalysts, the development of correlative in situ characterization technologies and the further coupling promising reactions for production of value-added products are examined for inspiring the future work.