Japanese scientists unlock the “holy grail” of green ammonia

A team of Japanese researchers have discovered a novel way to produce ammonia at lower temperatures and pressures than traditional methods, which has the potential to alter the production of this important chemical. A breakthrough published today in Natural Chemistry could greatly reduce the huge carbon footprint of global ammonia production, currently accounting for about 2% of world energy consumption.

A research team led by Professor Masaaki Kitano of the Tokyo Academy of Sciences has developed a new catalyst that can effectively convert nitrogen to ammonia without relying on traditional transition metals such as iron or fluoron. This development challenges a century of traditional concepts in chemical manufacturing.

“Due to its unique crystal structure and chemical properties, we focus on silicates (BA3SIO5), used to synthesise our novel catalysts, thus providing the potential to reduce energy demand and reduce operating conditions,” Kitano explained the material.

The new catalyst, called BA3SIO5-XNYHz, operates through a previously undiscovered mechanism involving atomic-scale vacancies in its crystal structure. The “pores” of these nanomirrors act as active sites where nitrogen molecules can be captured and converted to ammonia under mild conditions, rather than required by traditional processes.

Making this discovery particularly important is that the catalyst works without transition metals, which is the first in ammonia synthesis. When the researchers added a small amount of ruthenium to enhance performance, they discovered something unexpected: the only thing that didn’t do what scientists thought.

The catalyst reaches an ammonia synthesis rate of 40.1 mm per hour at only 300°C – the temperature is much lower than that of conventional industrial processes that usually operate above 400°C. More importantly, this performance exceeds existing catalysts under comparable conditions.

The development process itself represents a major innovation. The team synthesized its catalyst between 400-700°C, which is much lower than the 1100-1400°C required for traditional materials. This lower synthesis temperature not only makes yields more energy-saving, but also better controls the properties of the material.

The meaning of this discovery is not just about ammonia production. This study shows a new catalyst design method that can be applied to other important chemical processes. This can open up new avenues for developing more sustainable chemical manufacturing methods in various industries.

The material exhibits significant stability and maintains its performance over the long term, a key factor in industrial applications. When testing 150 hours of continuous operation, the catalyst showed no degradation, producing much more ammonia than its own composition could explain, proving that it was indeed catalyzing the reaction rather than simply decomposing the reaction.

The production of industrial ammonia is mainly used for fertilizers and currently relies on the century-old Haber-Bosch process, which operates at a temperature of around 450°C and has a pressure of up to 300 atmospheres. The energy-intensive nature of the process makes it an important contribution to global carbon emissions. New catalysts operate at lower temperatures and pressures, which can greatly reduce this environmental impact.

Researchers are now working to expand the process and optimize catalysts for industrial applications. Although challenges remain in the challenge of successfully converting laboratories to industrial scale, fundamental breakthroughs in understanding how non-converting metal catalysts activate nitrogen molecules open up new possibilities for sustainable chemical production.

This work was conducted in collaboration between the Tokyo Institute of Science, the National Institute of Materials Science and Tohoku University, an important step towards a more sustainable chemical manufacturing process that has the potential to reshape the world’s most energy-efficient One of the industrial processes.