Energizing Co Active Sites via d-Band Center Engineering in CeO 2 -Co 3 O 4 Heterostructures: Interfacial Charge Transfer Enabling Efficient Nitrate Electrosynthesis.

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 N 2 adsorption and activation processes. Herein, the research embarks on the development of a CeO 2 -Co 3 O 4 heterostructure, strategically engineered to facilitate the electron transfer from CeO 2 to Co 3 O 4 . This orchestrated transfer operates to amplify the d-band center of the Co active sites, thereby enhancing N 2 adsorption and activation dynamics by strengthening the Co─N bond and diminishing the resilience of the N≡N bond. The synthesized CeO 2 -Co 3 O 4 manifests promising prospects, showcasing a significant HNO 3 yield of 37.96 µg h -1 mg cat -1 and an elevated Faradaic efficiency (FE) of 29.30% in a 0.1 m Na 2 SO 4 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 N 2 on the surface of CeO 2 -Co 3 O 4 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 N 2 adsorption throughout the electrochemical NOR operations and delineates a blueprint for crafting highly efficient NOR electrocatalysts.