A joint research team from Osaka City University and Tohoku University has developed a solid catalytic system that is effective in breaking down polyolefin-based plastics for recycling. The cerium oxide-supported ruthenium (Ru/CeO2) catalyst created here marks the world’s first solid catalytic system able to facilitate the lower-temperature, high-yield synthesis of valuable lubricants and liquid chemicals.
The new catalyst makes it possible for reaction temperatures to be more than 100 degrees Celsius lower than other chemical recycling technologies such as pyrolysis or gasification; further, it is compatible with the recycling of ordinary plastic garbage bags and waste plastics. Building on this, the research team plans to bring about a novel catalyst process that will permit the chemical recycling of real-world plastics under moderate conditions.
These efforts come amid high hopes for chemical recycling processes, which are seen as having the potential to supply raw materials and chemicals while also reducing waste and carbon emissions. Some chemical recycling technologies, such as pyrolysis or gasification, have already been commercialized; however, they generally require temperatures in excess of 400 degrees Celsius. And their other drawbacks include the generation of low-value gas and multiple byproducts, along with catalyst deactivation.
In developing the new catalyst, the research team used polyethylene as a model substrate and discovered that the Ru/CeO2 catalyst demonstrated higher activity than other metal-supported catalysts. It enables polyolefins to be transformed into lubricants and liquid chemicals under low-temperature, low-hydrogen-pressure conditions of 200 degrees Celsius and 2 megapascals, yet still manages a yield as high as 90 percent or more.
The commercialization of this new catalyst will pave the way for plastic recycling based on an eco-friendly process. Further, its potential to let industry switch from petrochemical resources to chemical synthesis will reduce CO2 emissions, energy use and costs. So given the potential of this new catalyst technology to assist in creating a low-carbon society, further developments here will be under the spotlight going forward.