Metal/covalent-organic framework-based electrocatalysts for electrochemical reduction of nitrate to ammonia

The pervasive contamination of industrial, domestic, and agricultural wastewater with nitrate poses profound ecological and public health risks. Traditional methods for remediating nitrate-laden water face formidable challenges due to its high solubility and stability. However, a promising solution emerges in the form of electrochemical nitrate reduction (eNO₃RR), offering both efficient nitrate removal and valuable ammonia generation in a sustainable manner. This review explores the burgeoning field of eNO₃RR, focusing on recent advancements utilizing porous crystalline framework materials − metal–organic frameworks (MOFs) and covalent-organic frameworks (COFs) − as a novel class of electrocatalysts. These innovative materials exhibit unique properties such as adjustable porosity, diverse structures, tunable pore sizes, and well-defined active sites, making them ideal candidates for enhancing the efficiency and selectivity of nitrate reduction under ambient conditions. By dissecting the structure–activity relationship inherent in MOF/COF-based electrocatalysts, this review aims to provide a comprehensive understanding of their role in driving the conversion of NO₃⁻ to NH₃. Moreover, it identifies current challenges and proposes future prospects for leveraging these advanced materials in the sustainable conversion of nitrate pollutants, offering a glimpse into a greener and more effective approach to water remediation and resource recovery.