Recycling, reusing, and repurposing — the well-known “three Rs” of sustainability — aim to reduce environmental impact by cutting consumption, transforming waste, and giving materials a second life. While this idea is easy to grasp when thinking about plastics or clothing, it can also apply to something we cannot see or touch: carbon dioxide (CO₂). Widely associated with climate change and the greenhouse effect, CO₂ can also be understood as a form of waste. A new approach in chemistry, however, seeks to transform it into a valuable raw material.
This is the guiding principle behind the research led by Manuel Nappi at the Centre for Research in Biological Chemistry and Molecular Materials (CiQUS), University of Santiago de Compostela. The team has recently published a study in the Journal of the American Chemical Society (JACS) describing a new mechanism to activate CO₂ using light. “We use light in a similar way to how plants perform photosynthesis,” explains Nappi. “Combined with a catalyst, it allows us to activate carbon dioxide and transform it into molecules that may be useful for society.”
The main challenge with CO₂ lies in its high stability, which makes it difficult to transform. The strategy developed at CiQUS addresses this issue by enabling the conversion of CO₂ into a usable chemical building block, supporting more sustainable reaction pathways. In particular, the team explores hydrocarbonylation processes, where activated CO₂ is incorporated into organic molecules, contributing to the broader goals of circular chemistry.
At the core of this work is a novel catalytic system based on an organic molecule that generates a light-responsive reactive intermediate capable of activating CO₂. Once activated, the gas can participate in chemical reactions, including coupling with alkenes to form new compounds. Among the products obtained are spirolactones — structures of interest in the pharmaceutical industry — as well as compounds with potential applications in biodegradable polymers and resins.
Although the newly described mechanism is highly sustainable, the study still faces some limitations. At this stage, it represents a proof of concept carried out on a small scale. In addition, the reaction currently requires around 20 hours to complete. Future work will focus on improving catalytic efficiency and reducing reaction times.
Nappi emphasizes that this research is still at an early stage but holds strong potential. As a contribution to fundamental science, it lays the groundwork for future technologies aimed at CO₂ valorisation. “It is essential to continue supporting basic research,” he notes, “as many major technological advances originate from it.”
Ultimately, this work reflects a broader ambition shared by many researchers: to shift the paradigm towards a more sustainable chemistry, where even a waste product like CO₂ can be transformed into a valuable resource.
By Laura Filloy, GCiencia.
Reference
E. Azzi, M. Rodríguez-Martínez, S. R. N. Kolusu, J. Scarfiello, J. A. Varela, M. Nappi. Photolysis of CO2 Carbamate for Hydrocarboxylation Reactions. J. Am. Chem. Soc. 2026, 148, 3801–3810.
The CiQUS holds the CIGUS recognition by the Xunta de Galicia, that accredits the quality and impact of its research, and receives financial support from the European Union through the Galicia FEDER Program 2021-2027.