Interfacial electric field triggered N2 activation for efficient electrochemical synthesis of ammonia

Electrochemical nitrogen reduction reaction (ENRR) is a sustainable approach to producing carbon-free ammonia under ambient conditions, while its performance has been severely limited by the poor activity of electrocatalysts. Here, we report the deliberate modulation of interfacial electric field at the CoO-Co3O4 interface as an effective strategy for boosting ENRR performance. The prepared CoO-Co3O4 showed a promising NH3 yield of 59.96 mu g h-1 mgcat-1 and high Faradaic efficiency (FE) of 22.37 % in 0.1 M Li2SO4. In situ Raman spectroscopy, in situ Fourier transform infrared (FTIR) spectra and theoretical calculations demonstrated that the engineered strong interfacial electric field in CoO-Co3O4 electrocatalyst act synergistically to capture inert N2 by forming strong Co-N bonds. Subsequently, the interfacial electric field enhanced sigma-d orbital hybridization between N2 molecule and Co site of CoO-Co3O4, achieving highly efficient N2 molecule activation. This work provides a deep understanding of electric field effect on the performance of ENRR catalysts.