LAUSR

Electrochemical nitrogen reduction reaction (NRR) is a promising approach to convert earth‐adundant N2 into highly value‐added NH3. Herein, it is demonstrated that the heterogeneous Au–Fe3O4 nanoparticles (NPs) can be adopted as highly efficient catalysts for NRR. Due to the synergistic effect of the strong N2 fixation ability of Fe3O4 and the charge transfer capability of Au, the Au–Fe3O4 NPs show excellent performance with a high yield (NH3: 21.42 µg mgcat−1 h−1) and a favorable faradaic efficiency (NH3: 10.54%) at −0.2 V (vs reversible hydrogen electrode), both of which are much better than those of the Au NPs, Fe3O4 NPs, as well as core@shell Au@Fe3O4 NPs. It also exhibits good stability with largely maintained performance after six cycles. The N2 temperature‐programmed desorption, surface valance band spectra, and X‐ray photoelectron spectroscopy collectively confirm that Au–Fe3O4 NPs have a strong adsorption capacity for the reaction species and suitable surface structure for electronic transfer. The theoretical calculations reveal that Fe provides the active site to fix N2 into *N2H while introducing Au optimizes the adsorption of NRR intermediates, making the NRR pathway on Au–Fe3O4 along an energetic‐favorable process and enhancing the NRR.