Screening of 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 ammonia in a sustainable method. Unfortunately, the non-equilibrium adsorption of intermediates and sluggish multi-electron 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 metals (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 Faradaic efficiency of 96.3%, 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.