Boosted charge and proton transfer over ternary Co/CoO/CoB for electrochemical nitric oxide reduction to ammonia.

The electrochemical nitric oxide reduction reaction (NORR) holds a great potential for removing environmental pollutant NO and meanwhile generating high value-added ammonia (NH). Herein, we tactfully design and synthesize a ternary Co/CoO/CoB heterostructure that displays a high NH Faradaic efficiency of 98.8% in NORR with an NH yield rate of 462.18 µmol cm h (2.31 mol h g) at -0.5 V versus reversible hydrogen electrode, outperforming most of the reported NORR electrocatalysts to date. The superior NORR performance is attributed to the enhanced charge and proton transfer over the ternary Co/CoO/CoB heterostructure. The charge transfer between CoB and Co/CoO yields electron-deficient Co and electron-rich CoO. The electron-deficient Co sites boost HO dissociation to generate *H while the electron-rich low-coordination CoO sites promote NO adsorption. The *H formed on electron-deficient Co sites is more favorable to transfer to electron-rich CoO sites adsorbed with NO, facilitating the selective hydrogenation of NO. This study paves the way for designing and developing highly efficient electrocatalysts for electrochemical reduction of NO to NH.