Polypropylene-Derived Luminescent Carbon Dots
Yongqi Yang, Sneha Sreekumar, Robert V. Chimenti, Maxim Veksler, Kai Song, S ZHANG, Daphne Rodas, Victoria Christianson, Deirdre M. O’Carroll
Abstract
Polypropylene is one of the most challenging plastics to recycle or upcycle due to its excellent chemical and thermal stability. Here, we report an effective two-step synthesis to prepare carbon dots (CDs) from polypropylene (PP). In the first step, bulk PP is converted to PP nanoparticles (PP-NPs) by using a reprecipitation process. In the second step, the PP-NPs are carbonized by a hydrothermal treatment. The size, structure, and photonic properties of the PP-CDs vary significantly with hydrothermal treatment temperature. At higher temperature, the PP-CDs product is ∼2.5 nm in diameter with a quantum yield of 10.3% and is free from unconverted PP. At lower temperature (120 °C), the PP-CDs are large in size (∼70 nm) and exhibit low quantum yield (0.2%). This work demonstrates an effective method to fully convert polypropylene to carbon dots and shows a high degree of tunability in the size, structure, and photonic properties of the product.