Technological breakthroughs

Compiled by Bao Hien

The production of urea — the world's most widely used nitrogen fertilizer — has always required a mandatory intermediate step: synthesizing ammonia via the Haber-Bosch process, which consumes large amounts of energy and generates substantial CO₂ emissions. A research team in Australia has just unveiled an entirely different route: synthesizing urea directly through electrochemistry, combining CO₂ with nitrogen compounds found in polluted wastewater, bypassing the ammonia intermediate altogether.

The hard problem: bonding carbon with nitrogen under mild conditions

Chemically, urea is a molecule containing both carbon and nitrogen atoms. The biggest challenge in synthesizing urea directly from CO₂ and nitrogen compounds via electrochemistry lies in forming a controlled, stable carbon-nitrogen (C-N) bond — the two elements don't readily combine under such mild reaction conditions.

The research team tackled this with a dual-metal catalyst system made of copper and cobalt, operating at the atomic scale. According to the study's lead author, the catalyst was designed to "hold carbon- and nitrogen-based molecules together long enough for them to react."

Mechanism: each metal plays a distinct role

In-situ spectroelectrochemical analysis during the reaction — using infrared and Raman techniques at a synchrotron source — revealed that copper and cobalt don't behave identically but perform two complementary roles. Copper primarily stabilizes CO₂-derived intermediates (*CO and *COOH groups), while cobalt drives the reduction of nitrite (NO₂-) and stabilizes the *NH₂ group. The fact that these two types of intermediates — one carbon-based, one nitrogen-based — are generated simultaneously right at the interface between the two metals is what allows them to couple efficiently into a C-N bond, forming urea.

Control experiments made the irreplaceable role of each metal clear: a pure copper catalyst produced no C-N-bonded products at all, yielding only formate and alcohols; a pure cobalt catalyst mainly produced ammonium and hydrogen gas, with no urea formed either. Only when the two metals were combined at a shared interface did the carbon-nitrogen coupling reaction proceed efficiently.

Results: a 1:1 ratio performs best, stable over 48 hours

At a 1:1 copper-to-cobalt ratio, the catalyst system achieved a urea production rate of 61±6 mmol per hour per gram of catalyst, with a Faradaic efficiency (the share of electrical energy converted into the desired product) of 11±2%. The catalyst maintained stable production over a continuous 48-hour period, with metal loss under 10% — indicating reasonably good durability under the tested operating conditions.

Feedstock source: no need to capture CO₂ directly from the air

A notable aspect of the team's development direction is that the input CO₂ doesn't necessarily need to come from direct air capture technology — which is energy-intensive. Instead, the team prioritizes unavoidable industrial emission streams, such as emissions from cement plants, or CO₂ of biogenic origin from agricultural byproducts. On the nitrogen side, the feedstock is nitrate and nitrite — pollutant compounds commonly found in agricultural and industrial wastewater — meaning the process essentially treats two polluting waste streams at once while producing a valuable product.

The entire system is designed to run on renewable electricity (wind, solar), eliminating the need for the high temperatures and pressures characteristic of the traditional Haber-Bosch process.

Still at the laboratory stage

The research team confirms the technology remains under development, with early results "showing promising selectivity under laboratory conditions" — in other words, there is still a considerable gap before commercialization becomes possible. The current 11% Faradaic efficiency remains low relative to what would be needed for large-scale industrial application, and the study does not yet address other important factors such as an economic comparison with the traditional Haber-Bosch process or a roadmap toward pilot-scale testing. Even so, demonstrating that the carbon-nitrogen coupling mechanism actually works on a specific bimetallic catalyst system — rather than remaining a theoretical hypothesis — is considered an important step forward for the field of electrochemical urea synthesis, which remains in its early stages globally.

Source:
Ramadhany, P., Trần-Phú, T., Yuwono, J. A., Hocking, R. K., Ma, Z., Ta, X. M. C., Kumar, P., Gunawan, D., Johannessen, B., Tricoli, A., Simonov, A. N., Amal, R., & Daiyan, R. (2026). Spectroelectrochemical insight into copper cobalt catalysts for CO2 and nitrite co-electroreduction to urea. Nature Communications, 17, Article 1776. 

https://doi.org/10.1038/s41467-026-68481-6