Nanomaterials in electrochemical nitrate reduction

Nitrate has been considered a contaminant in water bodies, and excess nitrate derived from the abusive spread of nitrogen-containing fertilizers causes adverse effects on aquatic organisms and humans. Traditional methods usually focus on denitrification (nitrate to nitrogen gas) via dissimilatory pathways in microorganisms. However, this time-wasting method can no longer meet the goal of sustainability due to the generation of secondary wastes. Electrochemical nitrate reduction reaction (NO3RR) has been proposed as a more energy-efficient and cost-effective process, with valuable chemicals produced, such as highly concentrated ammonium solution and solid urea, pushing the traditional ammonia industry, based on the Haber-Bosch process into the circular economy. This chapter mainly introduces the recently studied electrocatalysts used in the NO3RR process, summarizing relevant mechanisms and product detection methods. Additionally, NO3RR can potentially construct a Zn-nitrate battery to work as a power source, and this emerging direction will probably overturn conventional ammonia production. © 2024 Elsevier Inc. All rights reserved.