2023-12-23 23:10:00
In a world where tackling climate change has become a priority, researchers have embarked on a quest to transform CO2, a harmful greenhouse gas, into a valuable resource. Find out how they are pushing the boundaries of technology to achieve this goal.
Research groups around the world are working on developing technologies to convert carbon dioxide (CO2) into raw materials for industrial applications. Most experiments conducted under industrially relevant conditions have been carried out with heterogeneous electrocatalysts, that is, catalysts that are in a different chemical phase from the reacting substances.
Homogeneous catalysts, which are in the same phase as the reactants, are however generally considered more efficient and selective. Until now, there were no setups where homogeneous catalysts could be tested under industrial conditions.
A team led by Kevinjeorjios Pellumbi and Professor Ulf-Peter Apfel of theRuhr University and theFraunhofer Institute for environmental, safety and energy technology UMSICHT in Oberhausen has now filled this gap.
Long-term effectiveness and stability
The team explored the conversion of CO2 using electrocatalysis. In this process, a voltage source provides electrical energy, which is fed to the reaction system via electrodes and drives the chemical conversions at the electrodes. A catalyst facilitates the reaction; In homogeneous electrocatalysis, the catalyst is usually a dissolved metal complex.
In a so-called gas diffusion electrode, the starting material CO2 flows past the electrode, where catalysts convert it into carbon monoxide. The latter is in turn a common raw material in the chemical industry.
The researchers integrated the metal complex catalysts into the electrode surface without chemically bonding them to it. They showed that their system could efficiently convert CO2: it generated current densities of more than 300 milliamps per square centimeter. Additionally, the system remained stable for over 100 hours without showing any signs of degradation.
Synthetic
The results of this research show that homogeneous catalysts can generally be used for electrolysis cells. However, they require a specific electrode composition.
Specifically, the electrodes must enable direct gas conversion without solvents so that the catalyst is not leached from the electrode surface. Contrary to what is often described in the specialized literature, it is not necessary to have a carrier material which chemically couples the catalyst to the surface of the electrode.
« Our results open the possibility of testing and integrating high-performance, easily variable homogeneous electrocatalysts in application scenarios for electrochemical processes. », concludes Ulf-Peter Apfel.
For a better understanding
What is electrocatalysis?
Electrocatalysis is a process that uses a voltage source to provide electrical energy, which is fed to the reaction system via electrodes and drives the chemical conversions at the electrodes.
What is a homogeneous catalyst?
A homogeneous catalyst is one that is in the same phase as the reactants. They are generally considered more efficient and selective.
What is a heterogeneous catalyst?
A heterogeneous catalyst is a catalyst that is in a different chemical phase from the reacting substances.
What is carbon monoxide?
Carbon monoxide is a gas that is a common raw material in the chemical industry. It is produced by the conversion of CO2 by electrocatalysis.
What is CO2 conversion?
CO2 conversion is a process that transforms carbon dioxide, a harmful greenhouse gas, into a valuable resource for industrial applications.
References
Légende illustration principale : “Kevinjeorjios Pellumbi with the experimental setup for CO2 conversion” – Crédit : RUB, Marquard
Article : “Pushing the Ag-loading of CO2 electrolyzers to the minimum via molecularly tuned environments” – DOI: 10.1016/j.xcrp.2023.101746
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#catalytic #system #CO2 #conversion