Photothermal recycling of waste polyolefin plastics into liquid fuels with high selectivity under solvent-free conditions

Abstract

Abstract The widespread use of polyolefin plastics in modern societies generates huge amounts of plastic waste. With a view toward sustainability, researchers are now seeking novel and low-cost strategies for recycling and valorizing polyolefin plastics. Herein, we report the successful development of a photothermal catalytic recycling system for transforming polyolefin plastics into liquid/waxy fuels under concentrated sunlight or xenon lamp irradiation. Photothermal heating of a Ru/TiO2 catalyst to 200–300 °C in the presence of polyolefin plastics results in intimate catalyst-plastic contact and controllable hydrogenolysis of C-C and C-H bonds in the polymer chains (mediated by Ru sites). By optimizing the reaction temperature and pressure, the complete conversion of waste polyolefins into valuable liquid fuels (86% gasoline- and diesel-range hydrocarbons, C5-C21) is possible in short periods (3 h). This work demonstrates a simple and efficient strategy for recycling waste polyolefin plastics using abundant solar energy.