Tuesday, 26 March 2024
Researchers have successfully transformed CO2 into methanol by shining sunlight on single atoms of copper deposited on a light-activated material, a discovery that paves the way for creating new green fuels.
An international team of researchers from the University of Nottingham's School of Chemistry, University of Birmingham, University of Queensland and University of Ulm have designed a material, made up of copper anchored on nanocrystalline carbon nitride. The copper atoms are nested within the nanocrystalline structure, which allows electrons to move from carbon nitride to CO2, an essential step in the production of methanol from CO2 under the influence of solar irradiation. The research has been published in the Sustainable Energy & Fuels Journal of the Royal Society of Chemistry.
In photocatalysis, light is shone on a semiconductor material that excites electrons, enabling them to travel through the material to react with CO2 and water, leading to a variety of useful products, including methanol, which is a green fuel. Despite recent progress, this process suffers from a lack of efficiency and selectivity.
Carbon dioxide is the greatest contributor to global warming. Although, it is possible to convert CO2 to useful products, traditional thermal methods rely on hydrogen sourced from fossil fuels. It is important to develop alternative methods based on photo- and electrocatalysis, taking advantage of the sustainable solar energy and abundance of omnipresent water.
There is a large variety of different materials used in photocatalysis. It is important that the photocatalyst absorbs light and separates charge carriers with high efficiency. In our approach, we control the material at the nanoscale. We developed a new form of carbon nitride with crystalline nanoscale domains that allow efficient interaction with light as well as sufficient charge separation.
The researchers devised a process of heating carbon nitride to the required degree of crystallinity, maximising the functional properties of this material for photocatalysis. Using magnetron sputtering, they deposited atomic copper in a solventless process, allowing intimate contact between the semiconductor and metal atoms.
Tara LeMercier, a PhD student who carried out the experimental work at the University of Nottingham, School of Chemistry, said: “We measured the current generated by light and used it as a criterion to judge the quality of the catalyst. Even without copper, the new form of carbon nitride is 44 times more active than traditional carbon nitride. However, to our surprise, the addition of only 1 mg of copper per 1 g of carbon nitride quadrupled this efficiency. Most importantly the selectivity changed from methane, another greenhouse gas, to methanol, a valuable green fuel.”
Carbon dioxide valorisation holds the key for achieving the net-zero ambition of the UK. It is vitally important to ensure the sustainability of our catalyst materials for this important reaction. A big advantage of the new catalyst is that it consists of sustainable elements – carbon, nitrogen and copper – all highly abundant on our planet.
This invention represents a significant step towards a deep understanding of photocatalytic materials in CO2conversion. It opens a pathway for creating highly selective and tuneable catalysts where the desired product could be dialled up by controlling the catalyst at the nanoscale.
This work is funded by the EPSRC Programme Grant ‘Metal atoms on surfaces and interfaces (MASI) for sustainable future’ www.masi.ac.uk which is set to develop catalyst materials for the conversion of three key molecules - carbon dioxide, hydrogen and ammonia – crucially important for economy and environment. MASI catalysts are made in an atom-efficient way to ensure sustainable use of chemical elements without depleting supplies of rare elements and making most of the earth's abundant elements, such as carbon and base metals.
The University of Nottingham is dedicated to championing green and sustainable technologies. The Zero Carbon Cluster has been set in the East Midlands to accelerate the development and deployment of innovation in green industries and advanced manufacturing.
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More information is available from Professor Andrei Khlobystov on andrei.khlobystov@nottingham.ac.uk or
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About the University of Nottingham
Ranked 32 in Europe and 16th in the UK by the QS World University Rankings: Europe 2024, the University of Nottingham is a founding member of the Russell Group of research-intensive universities. Studying at the University of Nottingham is a life-changing experience, and we pride ourselves on unlocking the potential of our students. We have a pioneering spirit, expressed in the vision of our founder Sir Jesse Boot, which has seen us lead the way in establishing campuses in China and Malaysia - part of a globally connected network of education, research and industrial engagement.
Nottingham was crowned Sports University of the Year by The Times and Sunday Times Good University Guide 2024 – the third time it has been given the honour since 2018 – and by the Daily Mail University Guide 2024.
The university is among the best universities in the UK for the strength of our research, positioned seventh for research power in the UK according to REF 2021. The birthplace of discoveries such as MRI and ibuprofen, our innovations transform lives and tackle global problems such as sustainable food supplies, ending modern slavery, developing greener transport, and reducing reliance on fossil fuels.
The university is a major employer and industry partner - locally and globally - and our graduates are the second most targeted by the UK's top employers, according to The Graduate Market in 2022 report by High Fliers Research.
We lead the Universities for Nottingham initiative, in partnership with Nottingham Trent University, a pioneering collaboration between the city’s two world-class institutions to improve levels of prosperity, opportunity, sustainability, health and wellbeing for residents in the city and region we are proud to call home.
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