Recent progress on cobalt-based electrocatalysts for nitrate reduction to ammonia

A new review published in the journal Environmental Surfaces and Interfaces examines the most recent advances in cobalt‑based electrocatalysts. Researchers from Guizhou University and the Bioeconomy Science Institute in New Zealand analysed a wide range of cobalt‑containing materials, including monometallic cobalt, alloys, oxides, sulfides, phosphides, and metal‑organic frameworks (MOFs), as well as their derivatives.

“Cobalt is particularly attractive because it is abundant, inexpensive, and has a unique electronic structure that strongly adsorbs nitrate ions,” says corresponding author Professor Hu Li. “Cobalt atom's sp³ orbitals can form stable bonds with nitrate, facilitating the initial reduction step. Some Co‑based catalysts have achieved near‑100% Faradaic efficiency—meaning almost all the electrical current goes into producing ammonia rather than unwanted hydrogen gas.”

The key challenge in nitrate electroreduction is to control the reaction pathway so that the eight‑electron transfer yields ammonia rather than nitrite or nitrogen gas. “Our review shows that by alloying cobalt with other metals, introducing defects, or engineering the catalyst's crystal structure, we can fine‑tune the binding of intermediates and steer the reaction towards ammonia with high selectivity,” adds Li.

The researchers highlighted several notable examples: cobalt‑nickel alloys achieve industrial‑level current densities with 100% Faradaic efficiency in neutral media; phosphorus‑doped cobalt delivers ultra‑high ammonia production rates of over 200 mg h⁻¹ cm⁻²; and high‑entropy alloys containing cobalt exhibit ordered atomic arrangements that suppress competing hydrogen evolution, boosting both activity and stability.

Beyond material design, the review also discusses advanced strategies such as machine learning for high‑throughput catalyst screening, and the use of in‑situ characterisation techniques to monitor dynamic changes during reaction. The researchers envisioned integrated reactors that combine nitrate reduction with ammonia separation, paving the way for practical, large‑scale applications.

“This review provides a roadmap for developing next‑generation cobalt‑based electrocatalysts that can turn a global pollutant into a valuable resource,” says Li. “With continued research on catalyst durability and system engineering, nitrate‑to‑ammonia conversion could become a cornerstone of sustainable chemistry and circular economy.”

Contact author details:

Hu Li, State Key Laboratory of Green Pesticides, State‑Local Joint Laboratory for Comprehensive Utilization of Biomass, Center for R&D of Fine Chemicals, Guizhou University, Guiyang 550025, China. Email: hli13@gzu.edu.cn

Funder:

The work was funded by the Guizhou Provincial S&T Project (GCC[2023]011, QNA[2025]001, CXPTXM(2025)023).

Conflict of interest:

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

See the article:

Zhao, L., Zhou, M., Liu, L., Song, B., Yang, S., Li, H., Recent progress on cobalt‑based electrocatalysts for nitrate reduction to ammonia, Environmental Surfaces and Interfaces, 4 (2026) 364‑382. https://doi.org/10.1016/j.esi.2026.05.002