• The team from the Institute of Materials Science of Seville (CSIC–University of Seville) optimizes a formula to convert CO₂ into carbon monoxide.
• Researchers improve the catalyst’s conversion capacity up to 35.7%, reducing costs thanks to the low amounts of platinum required.
• This work contributes to the development of more efficient CO₂ recycling technologies, which are essential for advancing towards a low-carbon circular economy.

Researchers from the Institute of Materials Science of Seville (ICMS), at cicCartuja, a joint center of the Spanish National Research Council (CSIC) and the University of Seville, have designed a new catalyst that transforms carbon dioxide (CO₂)—one of the main gases responsible for climate change—into carbon monoxide (CO), a compound essential for the chemical and textile industries.

This new catalyst, composed of copper, potassium, platinum, and titanium (named PtCuK@), contributes to the goal of developing more efficient technologies for CO₂ recycling, which are necessary to advance towards a low-carbon circular economy. Specifically, the results published in the journal Materials Horizons demonstrate how this new catalyst, used as an accelerator in industrial reactors, is more sustainable because it extends the catalyst’s service life.

This new formula allows much larger amounts of CO₂ to be processed with a smaller quantity of catalyst, converting it into CO more selectively while avoiding its conversion into methane, one of the substances commonly produced by most current catalysts due to the use of low temperatures. “Precisely, this is another improvement of this technology: it has been possible to require lower temperatures to transform CO₂, consuming less energy and reducing costs,” stated the first author of the study and researcher at the University of Seville, Rubén Blay-Roger.

Furthermore, the resulting carbon monoxide has two main uses: storage and reuse in other industrial sectors, or recycling within the same industry where it is emitted. In the first case, it can be used in steel treatment, electronics, drug design, or the production of methanol, hydrocarbons, pharmaceuticals, and polymers. In the second case, with this new catalyst, the combustion reaction that generates the conversion to CO is coupled to another reaction required in a different reactor and used to produce fuels or aromatic compounds.

Unlike conventional methods for developing catalysts, which test many formulations and only evaluate final performance, the ICMS team studied what happens on the catalyst surface while it is operating. Thanks to this approach, they detected the formation of compounds that lead to catalyst deactivation, such as acrolein and carbonyl species, which are responsible for generating carbon deposits that “dirty” the material. With this information, the researchers adjusted the catalyst composition and added a very small amount of platinum, significantly reducing deposit formation, lowering the cost of the final catalyst, and improving long-term stability.

With this new catalyst, the researchers have succeeded in improving and optimizing industrial processes, providing greater catalyst stability. This characteristic is essential for industry because restarting a reactor to replace its catalyst generates not only high costs but also a significant environmental impact. In this regard, the new technology has not only increased stability but also extended catalyst lifetime, achieving performance for more than 60 hours and simple regeneration cycles. Specifically, the catalyst withstands a campaign of eight cycles alternating reaction and hydrogen regeneration.

In this research, carried out by the Surface Chemistry and Catalysis Group at ICMS in collaboration with the University of California, Santa Cruz (United States) and Beijing Forestry University (China), catalysts were prepared using copper encapsulated in titanium oxide, with potassium as a promoter. A selection of materials was then studied to determine whether their electronic structure was maintained during the catalytic process. To achieve this, different spectroscopic analyses were conducted to observe what was happening on the catalyst surface.

In this way, the team demonstrated improved catalyst performance, as the platinum-enhanced catalyst achieved a maximum conversion of 35.7%, compared to 19.6% for the material without platinum, while maintaining complete selectivity towards CO under the conditions evaluated. These figures exceed expected values because they minimize the amount of catalyst required relative to the amount of CO₂ to be converted.

This project was made possible through public funding from the Spanish Ministry of Science and Innovation via the SMART FTS project, together with funding from the Regional Government of Andalusia through the EMERGIA 2021 project and support from the Center for Research, Technology and Innovation (CITIUS).