Waste plastics transformed into chemicals with solar-powered catalyst

Waste plastics transformed into chemicals with solar-powered catalyst
by Simon Mansfield
Sydney, Australia (SPX) Aug 05, 2023

Photothermal catalysis, which is powered by clean solar energy, is emerging as an innovative means to transform waste plastic into valuable chemicals. This chemical conversion technique uses solar energy as a direct power source. Despite the potential, designing photothermal catalysts with both high conversion efficiency and significant catalytic activity has long been a formidable challenge.

In a groundbreaking move, a research team headed by Prof. Jinxing Chen of Soochow University in China has developed an advanced integrated photothermal catalyst, known as c-ZIF-8@SiO2. This development was presented in the Chinese Journal of Catalysis. The distinguishing feature of this catalyst is its ability to maximize the localized heating effect while minimizing thermal radiation loss, resulting in improved catalytic activity.

This newly introduced catalyst design integrates the use of ZIF-8 nanoparticles, synthesized via a template method. To assemble the integrated photothermal catalyst, c-ZIF-8@SiO2, a SiO2 layer is meticulously coated onto the surface of ZIF-8. This is subsequently subjected to a high-temperature carbonization process.

The intricate design features a carbon material inside the catalyst which captures solar energy, turning it into heat. On the other hand, the external SiO2 layer is permeable to solar light, allowing it to penetrate and be absorbed by the carbon center. This ingenious construction reduces the loss of thermal radiation from the carbon core, further magnifying the local thermal effect during the process of photothermal catalysis.

An additional advantage of the SiO2 outer layer is its protective capacity, which greatly improves the longevity and stability of the catalyst. Beyond this specific application, the approach to the catalyst's design hints at a generalized method that could amplify the local thermal effect in various photothermal catalytic systems.

Significantly, when exposed to sunlight, the c-ZIF-8@25SiO2 catalyst has demonstrated its ability to efficiently transform PET (polyethylene terephthalate) into its foundational monomers. Experiments involving PET glycolysis in natural sunlight conditions and the selective retrieval of PET from an assortment of plastics have further emphasized its promising role in photothermal catalytic PET glycolysis.

This approach to photothermal catalysis not only supports energy-saving and emission reductions, aligning with a greener and more sustainable trajectory but also introduces fresh and efficient methodologies for the chemical recycling of plastics.

Research Report:Highly efficient photothermal catalytic upcycling of polyethylene terephthalate via boosted localized heating