Electrochemical reduction of gaseous nitric oxide into ammonia: a review

Electrochemical reduction of gaseous nitric oxide gas is an appealing approach for simultaneously recycling nitric oxide and producing value-added ammonia. Indeed, ammonia finds applications in fertilizers production for agriculture, as a reagent in the pharmaceutical, explosive, and textile industries, and as a potential fuel for next-generation automotive fuel cells. Reduction of nitric oxide to ammonia using various electrode materials in electrochemical processes is reviewed. Materials primarily fall into two major categories: metal-based catalysts and carbon-supported catalysts. The key consideration and operational analysis to understand mechanistic reaction pathways and the selective production of product and intermediate are discussed from a prospective viewpoint.