Catalytic upcycling of silicone rubber by AlCl3 at low temperature

Chemical recycling of silicone rubber (SR) waste into valuable products has aroused ever-increasing attention; however, the development of a green, efficient degradation strategy for silicone rubber remains challenging. In this work, we report the catalytic upcycling of silicone rubber by AlCl 3 to produce SiO 2 under atmospheric environment. The optimized AlCl 3 /SR mass ratio, reaction temperature and time are 0.75, 280 ℃ and 120 min, respectively. The maximum yield of SiO 2 is 96 %. The as-prepared SiO 2 displays irregular spherical agglomerates with a particle size of 20–30 nm and bears rich micropores/mesopores/macropores. The result of variable-temperature Fourier-transform infrared spectroscopy proves that AlCl 3 promotes the fracture of Si-O in SR during heating. According to density functional theory, the addition of AlCl 3 leads to a decrease in the bond dissociation energy of Si-O and Si-C. The strategy achieves the green, efficient catalytic degradation of silicone rubber waste.