Energizing Co Active Sites via d-Band Center Engineering in CeO₂-Co₃O₄ Heterostructures: Interfacial Charge Transfer...

The electrochemical nitrogen oxidation reaction (NOR) holds significant potential to revolutionize the traditional nitrate synthesis processes. However, the progression in NOR has been notably stymied due to the sluggish kinetics of initial N₂ adsorption and activation processes. Herein, the research embarks on the development of a CeO₂-Co₃O₄ heterostructure, strategically engineered to facilitate the electron transfer from CeO₂ to Co₃O₄. This orchestrated transfer operates to amplify the d-band center of the Co active sites, thereby enhancing N₂ adsorption and activation dynamics by strengthening the Co─N bond and diminishing the resilience of the N≡N bond. The synthesized CeO₂-Co₃O₄ manifests promising prospects, showcasing a significant HNO₃ yield of 37.96 µg h^-1 mg_cat ^-1 and an elevated Faradaic efficiency (FE) of 29.30% in a 0.1 m Na₂SO₄ solution at 1.81 V versus RHE. Further substantiating these findings, an array of in situ methodologies coupled with DFT calculations vividly illustrate the augmented adsorption and activation of N₂ on the surface of CeO₂-Co₃O₄ heterostructure, resulting in a substantial reduction in the energy barrier pertinent to the rate-determining step within the NOR pathway. This research carves a promising pathway to amplify N₂ adsorption throughout the electrochemical NOR operations and delineates a blueprint for crafting highly efficient NOR electrocatalysts.