In a groundbreaking discovery, an international team of researchers has successfully transformed carbon dioxide (CO2) into methanol using a novel photocatalytic process. By shining sunlight on single atoms of copper deposited on a light-activated material, the researchers have paved the way for creating new green fuels that could help combat global warming.
The research, published in the journal “Sustainable Energy & Fuels,” was conducted by a collaborative team from the University of Nottingham’s School of Chemistry, University of Birmingham, University of Queensland, and University of Ulm. The team designed a unique material consisting of copper atoms nested within a nanocrystalline carbon nitride structure, which allows electrons to move from the carbon nitride to CO2 – a crucial step in the production of methanol from CO2 under solar irradiation.
Photocatalysis is a process in which light is shone on a semiconductor material, exciting electrons and enabling them to travel through the material to react with CO2 and water. This reaction can lead to the production of various useful products, including methanol, a green fuel. However, despite recent advancements, photocatalysis has suffered from a lack of efficiency and selectivity.
Carbon dioxide is the most significant contributor to global warming, and while it is possible to convert CO2 into useful products, traditional thermal methods rely on hydrogen sourced from fossil fuels. Developing alternative methods based on photo- and electrocatalysis, which take advantage of sustainable solar energy and abundant water, is crucial for a greener future.
Dr. Madasamy Thangamuthu, a research fellow at the University of Nottingham’s School of Chemistry and co-leader of the research team, emphasized the importance of controlling 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,” he explained.
The researchers devised a process of heating carbon nitride to the required degree of crystallinity, maximizing its functional properties 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 Ph.D. student who carried out the experimental work at the University of Nottingham School of Chemistry, highlighted the remarkable efficiency of the new 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.”
Professor Andrei Khlobystov from the University of Nottingham’s School of Chemistry emphasized the importance of carbon dioxide valorization in achieving the UK’s net-zero ambition. “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,” he said.
This breakthrough represents a significant step towards understanding photocatalytic materials in CO2 conversion and opens up a pathway for creating highly selective and tunable catalysts. By controlling the catalyst at the nanoscale, researchers can potentially “dial up” the desired product, making the process more efficient and environmentally friendly.
As the world continues to grapple with the challenges of climate change, discoveries like this offer hope for a more sustainable future. By harnessing the power of sunlight and single atoms, we can move closer to a world powered by green fuels and reduce our reliance on fossil fuels.
