Adsorbing and Activating N 2 on Heterogeneous Au–Fe 3 O 4 Nanoparticles for N 2 Fixation

Electrochemical nitrogen reduction reaction (NRR) is a promising approach to convert earth‐adundant N 2 into highly value‐added NH 3 . Herein, it is demonstrated that the heterogeneous Au–Fe 3 O 4 nanoparticles (NPs) can be adopted as highly efficient catalysts for NRR. Due to the synergistic effect of the strong N 2 fixation ability of Fe 3 O 4 and the charge transfer capability of Au, the Au–Fe 3 O 4 NPs show excellent performance with a high yield (NH 3 : 21.42 µg mg cat −1 h −1 ) and a favorable faradaic efficiency (NH 3 : 10.54%) at −0.2 V (vs reversible hydrogen electrode), both of which are much better than those of the Au NPs, Fe 3 O 4 NPs, as well as core@shell Au@Fe 3 O 4 NPs. It also exhibits good stability with largely maintained performance after six cycles. The N 2 temperature‐programmed desorption, surface valance band spectra, and X‐ray photoelectron spectroscopy collectively confirm that Au–Fe 3 O 4 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 N 2 into *N 2 H while introducing Au optimizes the adsorption of NRR intermediates, making the NRR pathway on Au–Fe 3 O 4 along an energetic‐favorable process and enhancing the NRR.