Progress of electrochemical Synthesis of Nitric Acid: Catalyst Design-Mechanistic insights-Protocol-Challenges

Nitrogen-based fertilizers are necessary to increase the agricultural output since nitrogen is the most frequent rate-limiting product. The main ingredients in almost all nitrogen-based fertilizers are ammonia and nitric acid; demand for these substances is significantly driven by global population and food production. Over the next few decades, the size and value of the ammonia and nitric acid markets will continue to be largely influenced by global population, which will have a significant impact on energy utility. Ammonia is synthesized via the high energy demanding Haber-Bosch process, and in the Ostwald process, ammonia is catalytically oxidized to prepare industrial grade nitric acid. As industrial synthesis of nitric acid requires astronomical units of energy and emits greenhouse gases into the atmosphere at an alarming rate. Hence, there is an immediate need to find an eco–friendlier alternative route to produce nitric acid. In the approaching century, the most advantageous method that has the potential to significantly alter the human lifestyle is the electrochemical production of nitrate/nitric acid by nitrogen oxidation. In this review article, we have discussed designs of catalysts, mechanistic insights and strategy adapted for in the electrochemical nitrogen oxidation reaction (N2OR). Emphasis has been made on the various challenges that exist during N2OR and the possible solution to overcome the hurdles.