Recent Progress of Electrochemical Nitrate Reduction to Ammonia on Copper‐Based Catalysts: From Nanoparticles to Single Atoms

Abstract

Ammonia (NH3) is a vital chemical for modern human society. It is conventionally produced by the energy‐ and emission‐intensive Haber–Bosch process. Alternatively, sustainable NH3 production from renewable electricity‐driven electrolyzers has emerged as a promising route. Particularly, NH3 synthesis from nitrate (NO3−), a common pollutant in water and soil, by the nitrate reduction reaction (NO3RR) has drawn wide attention. Among various catalysts demonstrated recently, copper (Cu)‐based catalysts have been recognized as attractive candidates due to their availability, good activity, high NH3 selectivity, and facile reaction kinetics. In this review, the recent progress of Cu‐based NO3RR catalysts from the reaction mechanistic fundamentals to various catalyst design strategies, aiming at providing an on‐time summary, is summarized, and perspectives that can guide the rational and on‐demand design of Cu‐ and other earth‐abundant metal‐based catalysts for selective NO3RR toward sustainable NH3 production are elucidated.

Enhancing Efficiency of Nitrate Reduction to Ammonia by Fe and Co Nanoparticles Based Bimetallic Electrocatalyst

“…In conclusion, the turn to non-platinum group metals, especially catalysts based on Fe, Co, Cu, and Ni, has opened more economical approaches to NO3RR since adsorption of *NO3 and its conversion to *NO2 occurs readily on the 3d-transition metal centers, and these metal centers play a crucial role mainly in the adsorption pathways at the O-and N-ends leading to the formation of NH3 [27].…”

CuO/Mn2O3 heterojunction for efficient electrochemical nitrate reduction to ammonia

“…Nevertheless, the NO 3 RR performance of single component Cu-based catalysts is still unsatisfactory, since it is difficult for Cu-based catalysts to desorb the intermediate NO x , and it is also not conducive to water splitting to form H* on the surface of the catalysts, hindering the subsequent reactions. 23,24 Thus, some strategies such as interface engineering, defect engineering, heteroatom doping, and construction of heterostructures, 25–27 have been applied for enhancing the NO 3 RR performance of Cu-based catalysts. Notably, manganese ions have multiple valence states, such as +2, +3, and +4, which is conductive to the electrochemical redox process.…”