New process converts the greenhouse gas very efficiently into chemically usable carbon monoxide
Through a catalyst reaction the greenhouse gases carbon dioxide and methane can be converted into chemically usable carbon monoxide.
Ghent (Belgium) - Plants convert the greenhouse gas carbon dioxide into photosynthesized energy into carbohydrates. In line with this biological model, numerous research groups around the world work on similar processes to obtain synthesis gas from CO2 and water. This gas mixture of hydrogen and carbon monoxide is suitable for the production of methanol, ammonia and other basic chemicals. Scientists have now developed an alternative procedure that could be used to generate carbon dioxide for carbon dioxide. In the trade journal "Science", they explain the details of the catalytic reaction, which could lead to an efficient and climate-friendly recycling of CO2 on an industrial scale.
"Compared to existing technologies, our process can convert three times more carbon dioxide into carbon monoxide," says Valdimir Galvita from the University of Ghent in Belgium. Together with his colleagues, he optimized the so - called dry reforming, in which methane (CH4) - the main component of natural gas and carbon dioxide the desired synthesis gas is produced. To date, two hydrogen and two carbon monoxide molecules have been obtained from a CH4 and CO2 molecule in a catalyst reaction. In the newly developed process, on the other hand, four carbon monoxide molecules could be obtained from three CO2 molecules and one CH4 molecule. The hydrogen was thereby bound in water molecules.
This significant increase in efficiency was made possible by a multi-stage process in which the researchers used small particles of iron oxide and calcium oxide in addition to a nickel catalyst. At high temperatures of at least 750 degrees Celsius, a molecule of CH4 and CO2 reacts to two molecules of hydrogen and two carbon monoxide molecules, supported by the nickel catalyst. In a subsequent redox reaction on iron and calcium oxide, two more CO2 molecules could be reduced to carbon monoxide.
This catalyst action has great potential to further promote the economic use of the greenhouse gas carbon dioxide. With the favorable metal nickel as a catalyst, the use of expensive precious metals can also be dispensed with. In further work steps, it must now be checked whether this process can be carried out on a larger scale with the highest possible efficiency. This could lead to the creation of a pilot plant for the production of synthesis gas from carbon dioxide.