Recent Progress and Perspectives on Transition Metal-Based Electrocatalysts for Efficient Nitrate Reduction

Abstract

Electrochemical nitrate reduction is the process of converting nitrate into ammonia or nitrogen using electric energy. This saves energy, protects the environment, and is an important technology for nitrogen resource recovery and water purification. This paper examines recent advances in electrochemical nitrate reduction technology research and analyzes the reaction mechanism and path of electrochemical nitrate reduction as well as the influence of various factors on the reaction path through thermodynamic and kinetic principles. Second, the catalytic performances of transition metal electrocatalysts in the form of single metals, alloys, oxides, and composites in electrochemical nitrate reduction are analyzed in detail, which lays the foundation for the rational development of new, efficient, and stable electrocatalysts. Finally, future development directions and prospects for electrochemical nitrate reduction technology are envisioned.

CuCo2O4/CuO Heterostructure with Oxygen Vacancies Induced by Plasma for Electrocatalytic Nitrate Reduction to Ammonia

“…However, the mechanism of electrocatalytic NO 3 ̅ reduction to NH 3 involves the eight-electron transfer process (NO 3 ̅ + 9H + + 8e – → NH 3 + 3H 2 O), which produces various nitrogen-containing intermediates such as *NO 2 ̅ , *NO, *N, *NOH, *NH 2 etc. − In the process of reducing NO 3 ̅ , the production of N 2 and H 2 requires a significant number of electrons, leading to a low Faraday efficiency for ammonia production, particularly at higher potentials. To enhance the Faraday efficiency of nitrate reduction and prevent the coupling of H–H and N–N, it is very pivotal to develop electrocatalysts with high activity and selectivity. , As indicated in recent studies, copper-based materials have attracted the attention of researchers owing to their excellent catalytic activity and cost-effectiveness . Copper-based materials have the potential to regulate the adsorption energy of various nitrogen-containing intermediates by optimizing the d-band center, thereby enhancing the intrinsic activity of the catalysts and improving the Faraday efficiency of NH 3 production.…”