Research Projects

Around 7.4 billion tons of waste plastic are currently discarded inside the planet, that amount is expected to rise to 40 billion metric tons until 2050.[1-2]The fact that less than 10% of plastics are recycled globally because there aren't enough, commercially viable recycling methods is even more startling. Over 70% of discarded plastics end up in landfills and the ocean, endangering the ecosystem worldwide.[3] Among non-fiber plastics like polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS) etc., polystyrene boasts a wide array of applications, ranging from packaging materials, construction products, medical uses, to the realm of arts and crafts, among others.[4] Researchers have found that plastic polymers can be converted into a variety of chemicals through pyrolysis, solvolysis, carbonization, photocatalysis and functionalization.[5] However, traditional thermochemical techniques, such as pyrolysis and gasification, which are typically characterized by severe reaction conditions, photocatalysis is regarded as a more gentle approach, owing to its environmentally friendly and cost-effective nature.The photocatalytic conversion of polystyrene (PS) into benzoic acid possibly facilitated by FeCl₃-based catalysts[6-7]because of its Lewis acidity. However, this reaction can be also feasible with highly strong Brønsted acidic sites such as sulfonic acid derivatives.[8,9] Recently, Xiao group reported phenothiazine derivative, PTH-3CN as efficient photocatalyst for oxidative depolymerization of wide variety of plastic.[10] Another important work was performed by Reisner group, where they utilized fluorenone organocatalyst for polystyrene to benzoic acid formation.[11] Despite recent advancements, the photochemical valorization of plastics continues to encounter significant obstacles that restrict its practical application in terms of recyclability. As a significant category of porous materials, versatile characteristics like high surface area, low density, robust framework are quite prominent feature in case of porous organic polymer (POP). The most attracting feature of POPs is their tunability, which encourage scientific community to design and develop materials by tuning their band gap, energy level as well as flexibility in order to get better optical performance.[12-16] Herein, we plan to develop series of phenothiazine (PTH) and fluorenone based POPs for visible light mediated depolymerization of polystyrene. Currently, Zhang et al. reported PTH-consisting POPs as a category of metal-free, robust, and recyclable heterogeneous photocatalysts designed for organic transformation reaction.[17] Shi and co-workers reported 9-fluorenone based POPs exhibited better aerobic oxidation ability than its homogeneous counterpart under visible light irradiation.[18] Considering the recent discovery we plan to develop most effective reusable photocatalyst for plastic degradation.(References are added to Methodology and Work plan)