Electrocatalytic conversion of nitrate waste into ammonia:a review

摘要

Xhe electrocatalytic reduction of nitrate waste into ammonia allows both the removal of nitrate contaminants and an alternative production of ammonia compared to the classical Haber-Bosch industrial process.Ammonia is useful in agriculture for manufacturing fertilizers,and as a reagent in pharmaceuticals,metallurgy,explosives,and the textile industry;ammonia is also an energy carrier in the automobile industry for next-generation fuel cells.Here we review the nitrate-to-ammonia conversion by electrocatalysis of industrial and agricultural waste,with focus on catalysts,reaction intermediates,side reactions,and reaction conditions.Electron transfer is facilitated by electrocatalysts with transition metals having occupied d-orbitals with similar energy levels to that of the nitrate lowest unoccupied molecular orbital.Green electro-conversion using carbon-based materials is also discussed.Results show nitrate conversion from 53 to 99.8 and ammonia selectivity from 70 to 97.4.