Screening of Intermetallic Compounds Based on Intermediate Adsorption Equilibrium for Electrocatalytic Nitrate Reduction to Ammonia

Abstract

Electrocatalytic nitrate (NO₃^-) reduction reaction (NO₃RR) holds great potential for the conversion of NO₃^- contaminants into valuable NH₃ in a sustainable method. Unfortunately, the nonequilibrium adsorption of intermediates and sluggish multielectron transfer have detrimental impacts on the electrocatalytic performance of the NO₃RR, posing obstacles to its practical application. Herein, we initially screen the adsorption energies of three key intermediates, i.e., *NO₃, *NO, and *H₂O, along with the d-band centers on 21 types of transition metal (IIIV and IB)-Sb/Bi-based intermetallic compounds (IMCs) as electrocatalysts. The results reveal that hexagonal CoSb IMCs possess the optimal adsorption equilibrium for key intermediates and exhibit outstanding electrocatalytic NO₃RR performance with a Faradaic efficiency of 96.3%, a NH₃ selectivity of 89.1%, and excellent stability, surpassing the majority of recently reported NO₃RR electrocatalysts. Moreover, the integration of CoSb IMCs/C into a novel Zn-NO₃^- battery results in a high power density of 11.88 mW cm^-2.