Recent progress in electrocatalytic reduction of nitric oxide to ammonia

Fossil fuel combustion results in significant NOx emissions, which are harmful to the environment and human health. The reasonable and effective treatment of NOx pollution is an urgent requirement. The electrocatalytic reduction of nitric oxide (NORR) to ammonia is an emerging method that can convert the NO pollutant into an important industrial product under ambient conditions, exhibiting great advantages over the severe reaction conditions of selective catalytic reduction (SCR) and Haber-Bosch processes of NH3 synthesis, therefore, attracting the great interest of researchers. In the last few years, lots of materials for NORR have been developed based on theoretical, computational, or experimental studies. However, further breakthroughs in the catalytic activity, selectivity, and Faraday efficiency of NORR electrocatalysts are required to address the limitations in practical applications. To help future research on NORR in both theoretical and experimental directions, we summarized the recent progress in the development of NORR electrocatalysts, classifying them into metals and alloys, metal compounds, and non-metal materials according to their nature. The mechanisms or reaction pathways of NORR are also discussed. Furthermore, the experimental parameters and devices for NORR are introduced to help with experimental studies in the future. The research directions and perspectives on the further development of NORR electrocatalysts are illustrated.