Solar-driven catalytic plastic upcycling

Abstract

Recent developments in photocatalytic plastic upcycling have focused on the C–H and C–C bond activation and cleavage. The generation of reactive oxygen species by photogenerated electrons can abstract the H atom from the plastic backbone. The photogenerated holes could also activate the C–H bonds directly and induce C–C bond cleavage. Several effective strategies significantly improve the valuable product selectivity, including the tandem photoredox strategy and the design of the photo-driven acid-catalytic system. Photothermal plastic upcycling combines the advantages of thermolysis and photocatalysis to achieve efficient light absorption and catalytic activity. The extensive use of plastic products has led to severe plastic pollution. The use of solar energy to drive waste plastic upcycling is expected to achieve simultaneous resource sustainability, clean energy storage, and environmental remediation. This article reviews the current strategies and mechanisms of solar-driven catalytic plastic upcycling. Photocatalytic upcycling allows the reaction to happen under mild conditions, and we discuss how to precisely control the catalytic potential to activate designated chemical bonds and selectively produce high value-added products. The photothermal catalytic process can combine the advantages of photocatalysis and thermal treatment, raising the reaction rate to the next level, and the rational catalyst designs are also prospected in detail based on previous research. The extensive use of plastic products has led to severe plastic pollution. The use of solar energy to drive waste plastic upcycling is expected to achieve simultaneous resource sustainability, clean energy storage, and environmental remediation. This article reviews the current strategies and mechanisms of solar-driven catalytic plastic upcycling. Photocatalytic upcycling allows the reaction to happen under mild conditions, and we discuss how to precisely control the catalytic potential to activate designated chemical bonds and selectively produce high value-added products. The photothermal catalytic process can combine the advantages of photocatalysis and thermal treatment, raising the reaction rate to the next level, and the rational catalyst designs are also prospected in detail based on previous research. a type of hydrocarbon cracking reaction. It describes the free radical-induced C–C bond cleavage. The unpaired electron is delocalized to form a C=C bond and breaks the two connected carbons to form an olefin. the incident light irradiating on a metal nanoparticle’s surface could result in the oscillation of electrons located on the conduction band. This effect enhances the electric field on the particle surface and the light absorption reaches a maximum at the plasmon resonant frequency. this term is not well understood yet. It represents the excessive energy between molecules or atoms that could convert into heat energy without light emission. The molecule will go back to its ground state after relaxation. an approach in photocatalysis that not only degrade plastic into other compounds but also can generate H2 fuel as the product. the photosensitizer absorbs light and converts it into another form of energy. It provides physiochemical changes to nearby molecules by donating an electron or abstracting a hydrogen atom from them. After the whole process, the photosensitizer will return to its original state, with intact chemical and physical properties. plastic upcycling is different from the recycling or degradation process. Instead, it involves recreating new materials from the original waste plastic. As a result, it provides a more valuable product than the other methods. a highly reactive and unstable oxygen-based molecule or radical (e.g., •OH). The highly reactive property allows it to attack the carbon backbone of plastic and induce depolymerization.