Blue light-Mediated Oxidative Degradation of Polystyrene by Ni(II)-Amido-Quinoline Complexes

Since 1950, more than 8 billion tons of plastic have been produced, with over 80% ending up as landfill waste or entering the environment, creating major health and environmental concerns and highlighting the need for sustainable conversion of plastic waste into valuable chemical feedstocks. Polystyrene (PS) is a widely used plastic in packaging, electronics, construction, and food containers, contributing nearly 6% of global plastic production. Due to its strong C–C and C–H bonds, PS is highly stable and resistant to degradation. Over the past two decades, only a few studies have reported catalytic oxidative degradation of polystyrene to benzoic acid, but their practical application is limited due to harsh reaction conditions, complex systems, and long reaction time. Here we report a sustainable and selective photo-mediated strategy for Polystyrene degradation using Ni(II)-amido-quinoline complexes under visible light in air and very low catalyst loading (0.2 mM), achieving a conversion of ~60% with 20% yield of benzoic acid. This work highlights a oxidative degradation of polystyrene waste to a valuable chemical benzoic acid ,acetophenone and benzaldehyde. Mechanistic investigations indicate that singlet oxygen is formed as the key ROS in the degradation. This work highlights an opportunity for converting plastic waste into valuable chemicals in air beneficial for plastic industries.