Efficient photodegradation of dyes using light-induced self assembly TiO2/β-cyclodextrin hybrid nanoparticles under visible light irradiation

A novel β-cyclodextrin (β-CD) grafted titanium dioxide (TiO2/β-CD) was synthesized through photo-induced self assembly methods, and its structure was characterized. The TiO2/β-CD hybrid nanomaterial showed high photoactivity under visible light irradiation (λ ≥ 400 nm and/or λ ≥ 420 nm) and simulated solar irradiation (λ ≥ 365 nm). Photodegradation of Orange II followed the Langmuir-Hinshelwood kinetics model. The initial rate R0 of Orange II degradation increased by 6.9, 2.6 and 1.9 times in the irradiation conditions of λ ≥ 420 nm, λ ≥ 400 nm and λ ≥ 365 nm, respectively. β-CD increased the lifetimes of the excited states of the unreactive guests and facilitated the electron transfer from the excited dye to the TiO2 conduction band, which enhanced the dye pollutant degradation. Superoxide radicals were shown to be the main reactive species that caused the degradation of Orange II under visible irradiation.