Relationships among structure, composition, and selectivity in the electrocatalytic reduction of nitrate ions

Electrochemical nitrate reduction reaction (NO3RR) is crucial in converting wastewater nitrate sources into value-added products under mild, low-cost conditions. Metals with highly occupied d-orbitals, such as Au, Ag, Cu, and Pt, are promising materials for high-performance electrocatalytic NO3-reduction due to their favorable surface electronic properties. While many metals are effective catalysts for NO3RR, their limited ability to favor specific products often hinders practical application. This short review analyzes recent understanding of the reaction mechanisms and pathways of NO3RR, focusing on the structural and electronic effects of the catalysts such as underpotential deposition systems and single-atom catalysts on product selectivity.