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Advanced Energy and Decarbonisation Office (AEDO)

Catalytic Process Using Ammonia as Hydrogen Source for Carbon Dioxide Conversion

1 October 2026

Affiliation

A*STAR

Focus topic

CO2-to-Chemicals and Fuels

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Summary

This patent discloses an integrated catalytic process that directly converts ammonia (NH₃) and carbon dioxide (CO₂) into syngas (CO + H₂) and/or light hydrocarbons, particularly methane, within a single reactor using a single catalyst. The invention eliminates the need for separate ammonia-cracking and CO₂-hydrogenation units by using ammonia as a hydrogen carrier and hydrogen source in situ. Transition-metal catalysts, particularly cobalt- and silica-supported systems, catalyze both ammonia decomposition and CO₂ conversion simultaneously, producing syngas with suitable H₂/CO ratios for downstream chemical synthesis. Unreacted ammonia and carbon dioxide are recovered as ammonium carbonate, bicarbonate, and/or carbamate and recycled back into the process, improving overall efficiency.

Key Achievements:

  1. Developed a single-reactor, single-catalyst process that integrates ammonia cracking and CO₂ conversion, reducing process complexity and capital cost

  2. Eliminates the need for intermediate hydrogen purification, storage, and transport infrastructure

  3. Utilizes ammonia as a high-density hydrogen carrier, overcoming challenges associated with hydrogen storage and logistics

  4. Produces syngas (CO + H₂) with tunable H₂/CO ratios suitable for fuels, methanol, ammonia, and chemical manufacturing

  5. Enables selective production of methane and other C1-C3 hydrocarbons through catalyst and process optimization.

  6. Achieves high catalyst stability, with demonstrated continuous operation exceeding 340 hours without significant carbon deposition

  7. Incorporates a closed-loop recycle strategy in which unreacted NH₃ and CO₂ are recovered as ammonium carbonate species and regenerated for reuse

  8. Operates without oxygen, resulting in negligible NOx formation, a significant environmental advantage over ammonia combustion routes.

What makes this novel compared to best-in-class technology?

Conventional CO₂ conversion routes require pure hydrogen as a feedstock, necessitating prior ammonia cracking or hydrogen storage infrastructure. This process uses ammonia directly as the hydrogen source in a single reactor, removing upstream processing steps and enabling green ammonia to serve as a drop-in feedstock.

TRL level

1-3

Relevant for

CO₂ emitters seeking on-site utilisation (refineries, petrochemical plants), syngas consumers, e-fuels and synthetic hydrocarbons producers

About

ASTAR logo

Inventors: Mingyao Kelvin Kwok, Luwei Chen, Chee Kok Poh, Sin Kim Tang

Affiliation: Agency for Science, Technology and Research (A*STAR), Institute Of Sustainability for Chemicals, Energy And Environment (ISCE2)

Contact A*STAR for licensing opportunities and more information.

Please quote ID ref [z2022-255] in your email.