The main process for industrial ammonia synthesis is the Haber-Bosch process, which is highly energy intensive with large amounts of CO2. The electrochemical ammonia synthesis is a potential alternative to the Haber-Bosch process because of its advantages of environmental friendliness; however, the inert N2 molecule adsorption and activation are difficult and the competition of the hydrogen evolution reaction (HER) leads to a low Faraday efficiency (FE) and NH3 yield of the nitrogen reduction reaction (NRR). The exploration of highly active and selective NRR catalysts that can efficiently adsorb and activate N2, as well as effectively inhibit the HER, is the key point of current research. In this study, NiFe-Nb2C catalysts were prepared by loading different Ni/Fe molar ratios of NiFe-LDH to Nb2C MXene and successfully introducing the synergistic effect between Ni and Fe. NiFe-Nb2C exhibited excellent NRR activity and the ammonia yield and FE hardly decreased in 4 consecutive cycle tests, and the current density remained stable in 24 h chronoamperometric tests, indicating that the NiFe-Nb2C catalyst has excellent electrochemical stability. DFT calculations indicate that the excellent NRR activity originated from the synergistic effect between NiFe-LDH and Nb2C MXene, which significantly promoted the activation of N2 and the formation of *N2H.
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