Exploring the Influence of Electronic Structure on Electrocatalytic Nitrate Reduction to Ammonia

Ammonia is a dynamic chemical precursor and energy carrier, traditionally manufactured through the Haber-Bosch process, which is an energy-intensive and carbon-emissive. As an alternative, the electrochemical nitrate reduction reaction to ammonia under ambient conditions has gained significant attention for its dual benefits of sustainable ammonia synthesis and nitrate pollutant remediation. Recent studies have shown that the electronic structure of the catalyst material strongly influences the catalytic efficiency of nitrate reduction. Modulation of the electronic structure via heteroatom doping, alloy formation, introduction of oxygen vacancies, strain engineering, and construction of phase boundaries alters the adsorption energies of key intermediates. Current studies on nitrate reduction to ammonia mostly focus on enhancing the Faradaic efficiency (FE) and yield rate up to industrial scale under harsh condition. However, the direct or indirect influence of ligand modulation, coordination engineering, and the introduction of a guest molecule into a host matrix toward electronic structure has rarely been discussed thoroughly. This review critically summarizes recent advances in electronic structure engineering for NO₃RR catalysts and elucidates the mechanistic role of electronic modulation in ammonia selectivity discussing the experimental and computational insights. By correlating chemical structure with catalytic performance, we provide a roadmap for designing next-generation electrocatalysts with superior nitrate-to-ammonia conversion efficiency.