Boosted charge and proton transfer over ternary Co/Co3O4/CoB for electrochemical nitric oxide reduction to ammonia

Abstract

Abstract The electrochemical nitric oxide reduction reaction (NORR) holds a great potential for removing environmental pollutant NO and meanwhile generating high value-added ammonia (NH3). Herein, we tactfully design and synthesize a ternary Co/Co3O4/CoB heterostructure that displays a high NH3 Faradaic efficiency of 98.8% in NORR with an NH3 yield rate of 462.18 µmol cm−2 h−1 (2.31 mol h−1 gcat −1) 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/Co3O4/CoB heterostructure. The charge transfer between CoB and Co/Co3O4 yields electron-deficient Co and electron-rich Co3O4. The electron-deficient Co sites boost H2O dissociation to generate *H while the electron-rich low-coordination Co3O4 sites promote NO adsorption. The *H formed on electron-deficient Co sites is more favorable to transfer to electron-rich Co3O4 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 NH3.