Atomically Precise Metal Nanoclusters: Advancing Electrocatalytic Nitrate-to-Ammonia Conversion

Abstract

Driven by the growing need for sustainable ammonia production and effective nitrate remediation, the electrocatalytic nitrate reduction reaction (NO3RR) has emerged as a promising technology. This process enables the conversion of nitrate pollutants into ammonia under mild operating conditions, offering a greener alternative to the energy-intensive Haber–Bosch route. However, the complex multielectron and multiproton transfer pathways involved in NO3RR require catalysts capable of precisely regulating intermediate adsorption, activation, and transformation. Atomically precise metal nanoclusters (NCs), with their well-defined atomic structures, tunable electronic properties, and identifiable active sites, have recently attracted considerable attention as model catalysts for elucidating structure–activity relationships. This perspective discusses the fundamental aspects of NO3RR, including key intermediates and reaction mechanisms, and summarizes recent advances in the use of atomically precise metal NCs for nitrate-to-ammonia conversion. The catalytic performances of mono-, bi-, and trimetallic NCs are systematically compared, highlighting the roles of active-site engineering, ligand modulation, heterometal incorporation, and cluster assembly in regulating activity and selectivity. The perspective concludes by discussing the key challenges that remain in this field and highlighting future research directions toward the development of NC-based electrocatalysts with enhanced activity, selectivity, and long-term stability for sustainable ammonia production.