Photochemical upcycling of polymers via visible light-driven C−H bond activation

The excessive use and improper disposal of plastics have placed a significant burden on the environment. To mitigate this impact, prioritizing the chemical upcycling of plastics is crucial. Unlike traditional thermochemical upcycling, which requires harsh conditions such as high temperatures and pressures, photochemical upcycling is viewed as a more environmentally friendly and cost-effective alternative. This includes using light to promote C-H bond activation to achieve the oxidative degradation of plastics, generating various valuable small molecules, or employing light-induced C-H bond activation for post-polymerization modification of post-consumer plastics to obtain polymers with enhanced properties. These methods are highly attractive approaches within the realm of chemical upcycling. This mini-review highlights the scientific breakthroughs in upcycling polymers through oxidative degradation and post-polymerization modification via visible light-driven C−H bond activation. In addition, the reaction mechanism, compatibility as well as practical application have been emphatically discussed.