Main-group elements boost electrochemical nitrogen fixation

Abstract

Renewable-energy-derived electrocatalytic nitrogen (N2) reduction reaction (NRR) is practically promising for the production of green ammonia (NH3). However, NRR is limited by low faradic efficiency and NH3 yield because of a high-energy barrier for N2 activation and competing hydrogen evolution reaction (HER). In contrast to widely investigated transition metals, main-group elements (MGEs) with manifold physicochemical properties and intrinsically poor hydrogen adsorption ability could provide superiority to address the challenges mentioned earlier. In this review, we (1) critically assess the use of MGEs in NRR by identifying the functional mechanism of boosting NRR and suppressing HER, (2) present a comprehensive summary of methodologies for N2 activation and HER suppression that are generalizable to advanced catalysts for N2 fixation, and (3) show MGEs-based mechanisms that can be judiciously applied for smart design of materials, electrolytes, and interface for electrocatalytic N2 reduction. We conclude that MGEs can significantly boost electrochemical N2 fixation.