Solar-powered efficient photocatalytic ammonia production
With a growing world population, we currently face the challenge of producing more food in a more sustainable manner. Ammonia-based fertilisers are important chemicals for crop growth that supports food production for over 48% of the world’s population. Ammonia production still relies on a centralised Haber-Bosch process. Although this process has been critical for the development of modern agriculture, it is also extremely carbon-intensive accounting for 1.8% of the global CO2 emissions.
Inspired by nature, Oxford academics have developed a novel photocatalyst that allows the conversion of nitrogen into ammonia under mild conditions and visible light intensities. This not allows for more sustainable production of ammonia, but it also opens the door to its decentralisation.
The importance of ammonia
As the world population continues to grow, the challenge of producing more food with less energy becomes an important issue to tackle. Current global food production heavily relies on the production of ammonia containing fertilisers, which support over 48% of the world’s population. The centralised Haber-Bosch process, considered the most important invention of the last century, is still the method of choice for artificial nitrogen fixation, providing more than half of the world’s ammonia.
Although this method has been critical for the development of modern agriculture, it is also extremely carbon-intensive accounting for 1.8% of the global CO2 emissions, which can be further exacerbated due to the lack of decentralised production options. Biological nitrogen fixation allows the synthesis of ammonia under ambient conditions with the use of the enzyme nitrogenase, however it still requires a large input of chemical energy provided from adenosine triphosphate (ATP) to convert molecular nitrogen into ammonia.
Although many research studies focus on mimicking the structure and function of nitrogenase, most of the efforts have been centred solely on enzymatic processes.
Sustainable photocatalytic ammonia production
Oxford researchers have targeted the sustainability challenge of ammonia production and developed a novel nitrogenase-like photocatalyst that allows efficient conversion of nitrogen into ammonia in aqueous and visible light conditions (e.g. solar) without the need for high temperature and pressure. In addition, the methodology is characterised by having:
- a high catalytic and quantum efficiency
- the absence of a sacrificial agent such as methanol or formaldehyde
Use of such catalyst would facilitate and promote renewable and local production of ammonia, crucial for crop production in both developed and developing countries.
Oxford University Innovation Ltd. has filed a priority patent application on the technology and welcomes discussions with companies interested in licensing it for commercial development.
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