Unveiling the Essential Nature of Lewis Basicity in Thermodynamically and Dynamically Promoted Nitrogen Fixation

Abstract

AbstractElectrochemical N2 reduction provides a promising alternative to the Haber–Bosch process for sustainable ammonia production but enhancing its selectivity and activity remains a significant challenge. Here, this issue is tackled by triggering strong Lewis basicity within the catalyst, which boosts ambient ammonia synthesis from both thermodynamic and dynamic viewpoints. The enhanced π back donation induced by the Lewis base as the electron donor is first confirmed by first‐principle calculations, which greatly activates the NN bond and promotes its dissociation. Moreover, as suggested by molecular dynamics simulations, such abundant Lewis base would contribute to more surface heterogeneity and thus enhanced van der Waals interactions between nitrogen and the catalyst. Localized high concentration of N2 molecules can be realized at the catalyst surface, enabling efficient N2 delivery with a high flux and benefiting the following reaction process. As expected, the proof‐of‐concept metal‐free catalyst achieves a Faradaic efficiency of 62.9% and ammonia yield rate of 41.1 µg h−1 mg−1 at −0.2 V versus reversible hydrogen electrode. With this Lewis base‐assisted strategy, the superior efficiency would greatly reduce the energy loss of the system and cut down the fundamental cost, thus contributing to future practical applications.