Synergistic Electrocatalysis for Enhanced Nitrate Valorization with Dual Strategies of Alternative Anode Reactions and Cathodic Coupling

Renewable electricity-driven nitrate reduction reaction (NO 3 RR) offers a sustainable strategy for simultaneously producing valuable chemicals and reducing environmental pollutants. Traditional systems integrating cathodic NO 3 RR with anodic oxygen evolution reaction (OER) are severely constrained by the inherent sluggish kinetics of OER, its single reaction pathway, and the low-value products produced, ultimately limiting overall process efficiency and economic viability. Current core solutions focus on two pathways, i.e., replacing OER with thermodynamically more favorable oxidation reactions and directed electrocatalytic coupling between nitrate species and carbon-containing substances at cathodic interfaces. This paper provides a concise review to traditional NO 3 RR mechanisms and catalyst preparation strategies while categorizing coupled systems into alternative anode coupling and cathodic coupling according to reaction locations. It analyzes mechanistic pathways for directional coupling of nitrates with other carbon-containing substances exemplified by urea formation at the same electrode interface and examines distinct product generation pathways and catalyst design strategies. Additionally, it comprehensively reviews recent advances in coupling cathodic NO 3 RR with various anodic oxidation reaction (AOR) processes, including reaction variations corresponding to different carbon-chain lengths, novel catalyst preparation strategies with potential mechanisms. Finally, current challenges and future research directions for NO 3 RR based coupled systems are discussed, aiming to provide scientific guidance for energy-efficient and highly efficient co-production of green ammonia and high-value-added chemicals.