New catalyst platform turns carbon emissions into plastic

The polluting emissions of petrochemical refineries could be captured and transformed into useable plastic thanks to new technology developed at the University of Southampton.

Aiming to reduce emissions and produce plastic in a sustainable way, a team of scientists invented the hybrid catalyst platform, known as Viridi CO₂. Created by Dr Daniel Stewart and Professor Robert Raja, the platform can reportedly convert carbon dioxide into versatile plastic materials in an efficient and sustainable way. It has been recognised by the Royal Society of Chemistry as a winner of its prestigious 2020 Emerging Technologies Competition.

The novel solution could be used to produce tens of millions of tonnes of plastics used annually in mattresses, clothing and building insulation, the team said. The technology could be retrofitted to the output streams of petrochemical refineries to close the ‘carbon loop’.

The hybrid, heterogeneous catalytic platform reportedly offers better opportunities for Carbon Capture Utilisation (CCU) than conventional Carbon Capture and Storage (CCS).  

The award-winning approach focused on the production of polyurethanes, which can be tailored to be either rigid or flexible. They are currently only created from fossil fuels and are single use. Deriving polyol – the starting material – from carbon dioxide allows the polymer to be broken down and recycled more easily at the end of its life.

Few catalysts are capable of performing this transformation, however. Current processes suffer from using highly toxic chemicals, or require synthetically demanding and costly processes to remove the catalyst from the polymer, as is the case for homogeneous catalysts. The few heterogeneous examples require extremely high pressures, temperatures and lengthy reaction times.

Viridi CO₂’s catalyst platform provides a route to polymer feedstocks that can be synthesised under more sustainable conditions, with energy savings of up to 75%.

“Our platform is capable of maximum carbon dioxide insertion under lower temperatures, pressures and dramatically reduced timeframes,” said Dr Stewart. “These benefits provide superior energy efficiency and high productivity, leading to reduced costs. Unlike other alternatives, these catalysts can also be reused and synthesised in minutes.”

The research team have filed a patent for the discovery and are preparing to commercialise the technology.

“This ground-breaking research is motivated by the lack of technologies utilising carbon dioxide as a viable synthetic feedstock, despite its low price and huge abundance,” said Professor Raja.

“Thirty million tonnes of polyurethanes are produced globally every year, yet they remain scarcely recyclable. They find use across many commercial sectors and the industry is set to grow to $70bn by the year 2022. In the presence of uniquely designed catalysts, up to 50% of the polyol feedstock mass can be replaced with carbon dioxide.

“By developing a platform-based design, we have shown that components of the catalyst can be modified, tuning the catalyst towards desired physical properties within the polymers. Having worked with multinational catalyst and petrochemical industries worldwide for over 20 years, we are optimistic the innovative and advanced characteristics of this catalyst platform can provide a significant manufacturing impetus to the UK chemical industry.”

The Viridi CO₂ platform was produced with research funding from the Engineering and Physical Sciences Research Council.

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