Nanoporous NiSb to Enhance Nitrogen Electroreduction via Tailoring Competitive Adsorption Sites

Abstract

Ambient nitrogen reduction reaction (NRR) is attracting extensive interest but still suffers from sluggish kinetics owing to competitive rapid hydrogen evolution and difficult nitrogen activation. Herein, nanoporous NiSb alloy is reported as an efficient electrocatalyst for N₂ fixation, achieving a high ammonia yield rate of 56.9 µg h^-1 mg^-1 with a Faradaic efficiency of 48.0%. Density functional theory calculations reveal that in NiSb alloy, Ni favors N₂ hydrogenation while the neighboring Sb separates active sites for proton and N₂ adsorption, which optimizes the adsorption/desorption of intermediates and enables an energetically favorable NRR pathway. This work indicates promising electrocatalytic application of the alloys of 3d and p block metals toward the NRR and provides an intriguing strategy to enhance the reduction of inert molecules by restraining the competitive hydrogen adsorption.