Greener Way To Make Ammonia With 'Molecular Microscope'

A team of researchers at Radboud University has discovered a promising new method to make ammonia – a key ingredient in fertilizers and many industrial chemicals – more efficiently and sustainably. Chemical scientist Evan Zhao: ‘This new method has zero CO₂ emissions, whereas the industrialized Haber-Bosch process is responsible for 3% of worldwide CO₂ emissions.’

Ammonia is used in many processes, not only in industry – for example, as a refrigerant in cooling installations or in the production of medicines – but also as a fertiliser and in the transportation of hydrogen. Zhao explains: ‘At present, ammonia is produced using the centuries-old Haber–Bosch process, which consumes huge amounts of energy and produces large CO_₂ emissions. Ammonia production currently accounts for 3% of global CO_₂ emissions.’ Scientists have long searched for cleaner alternatives, but many experimental methods have suffered from low efficiency and instability. 

Molecular microscope 
Using advanced Nuclear Magnetic Resonance (NMR) techniques, the research team, consisted of Luo, Aspers, Gunnarsdóttir and Zhao, can observe chemical reactions in real time. ‘It’s a kind of molecular microscope that allows us to actually see how ammonia is formed. These insights enabled us to design a new reaction cycle that not only produces ammonia, but also generates valuable green chemicals that can be used in industry, such as acetic acid or furandicarboxylic acid.’  By contrast, the conventional method produces either water or solvent degradation products. This dual benefit slashes the energy cost of ammonia production to about half of that of the conventional process. 

Zhao and Luo, together with Radboud University, have filed a patent to protect this new technology, as it has great potential for a wide range of real-world applications. Zhao adds: “In the future, this approach could make it possible to produce ammonia locally using renewable electricity. This ammonia could also help to transport hydrogen much more efficiently.’ However, several steps remain before this becomes a reality: ‘We have now demonstrated on a small scale that we can produce ammonia in this way. In the next few years, we will explore how to scale up the process, which will hopefully lead to many promising developments in the future.’