The continuous increase in manufacturing coupled with the difficulty of recycling of plastic products has generated huge amounts of waste plastics. Most of the existing chemical recycling and upcycling methods suffer from harsh conditions and poor product selectivity. Here we demonstrate a photocatalytic method to oxidize polystyrene to aromatic oxygenates under visible light irradiation using heterogeneous graphitic carbon nitride catalysts. Benzoic acid, acetophenone, and benzaldehyde are the dominant products in the liquid phase when the conversion of polystyrene reaches >90% at 150 °C. For the transformation of 0.5 g polystyrene plastic waste, 0.36 g of the aromatic oxygenates is obtained. The reaction mechanism is also investigated with various characterization methods and procedes via polystyrene activation to form hydroxyl and carbonyl groups over its backbone via C–H bond oxidation which is followed by oxidative bond breakage via C–C activation and further oxidation processes to aromatic oxygenates.

制造业的不断增加，加上塑料制品的回收困难，产生了大量的废塑料。大多数现有的化学回收和升级回收方法都存在条件恶劣和产品选择性差的问题。在这里，我们展示了一种使用非均相石墨氮化碳催化剂在可见光照射下将聚苯乙烯氧化为芳族含氧化合物的光催化方法。当聚苯乙烯的转化率在 150 °C 时达到 >90% 时，苯甲酸、苯乙酮和苯甲醛是液相中的主要产物。对于 0.5 克聚苯乙烯塑料废料的转化，得到 0.36 克芳族含氧化合物。