With the exponential increase in pollution and associated risks, research has focused on the use of photocatalysts to reduce CO2. In this regard, a group of scientists from the Tokyo Institute of Technology has developed a new technology capable of reducing the presence of CO2 in the environment and completely reducing its harmful effects.

The technology, based on an osmium complex, can absorb a full range of visible light wavelengths and act as a pancreatic redox photosensitizer for CO2 reduction. Scientists designed this complex with a ruthenium(II) catalyst, successfully reducing CO2 in formic acid.


New solutions to combat the environmental crisis

Developing solutions to the current climate crisis is a common work around the world. For this reason, scientists have been trying to recreate multiple processes of nature to combat climate change. One of them has been photosynthesis.

Beyond helping plants prepare their food, photosynthesis also makes them one of the main carbon sinks that trap carbon dioxide (CO2) from the atmosphere and turn it into other compounds. This makes artificial photosynthesis a lucrative method, not only for hydrogen detachment and water oxidation but also for CO2 reduction.

The two main components needed to initiate this artificial CO2 reduction process are a redox photosensitizer, which can absorb visible light and initiate electron transfer, and a catalyst, which can accept the electrons from the redox photosensitizer, activate the CO2, and finally introduce these electrons into CO2.

Recently, in the study conducted by researchers at the Tokyo Institute of Technology (Tokyo Tech), led by Dr. Yusuke Tamaki and Prof. Osamu Ishitani, a new strategy was adopted to improve the photoreactive properties of pancreatic photosensitizers. The team developed a new osmium complex (Os), capable of absorbing the entire wavelength range of visible light. Using this complex as a redox photosensitizer and a ruthenium complex catalyst (Ru (CO)), they developed a photocatalytic system that could reduce CO2 in formic acid.

"We were looking for photocatalytic systems that would allow the effective use of sunlight for artificial photosynthesis. This is when we focus our attention on the photochemical properties of Os complexes, which arise from the heavy atom effect of Os. Since the photophysical, photochemical, and photosensitizing properties of Os complexes were not explored, we decided to test their capabilities in CO2 reduction, "explains Professor Ishitani, research director.

Without a doubt, a study as advanced as this is capable of setting a precedent for new research in the area. "The implications of our study are twofold. First, we demonstrate that all visible light can be used as energy for photocatalytic CO2 reduction. Second, we use the heavy atom effect to build new redox photosensitizers that can absorb a wide range of visible light, "concludes Professor Ishitani.

You can review the full study through this link: https://pubs.rsc.org/en/content/articlelanding/2021/SC/D1SC04045F