The Effect of AgInS2, SnS, CuS2, Bi2S3 Quantum Dots on the Surface Properties and Photocatalytic Activity of QDs-Sensitized TiO2 Composite.

The effect of type (AgInS₂, SnS, CuS₂, Bi₂S₃) and amount (5, 10, 15 wt%) of quantum dots (QDs) on the surface properties and photocatalytic activity of QDs-sensitized TiO₂ composite, was investigated. AgInS₂, SnS, CuS₂, Bi₂S₃ QDs were obtained by hot-injection, sonochemical, microwave, and hot-injection method, respectively. To characterize of as-prepared samples high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis spectroscopy and photoluminescence (PL) emission spectroscopy were applied. The size of AgInS₂, SnS, CuS₂, Bi₂S₃ QDs were 12; 2–6; 2–3, and 1–2 nm, respectively. The QDs and QDs-sensitized TiO₂ composites obtained have been tested in toluene degradation under LEDs light irradiation (λ_max = 415 nm and λ_max = 375 nm). For pristine QDs the efficiency of toluene degradation increased in the order of AgInS₂ < Bi₂S₃ < CuS < SnS under 375 nm and AgInS₂ < CuS < Bi₂S₃ < SnS under 415 nm. In the presence of TiO₂/SnS QDs_15% composite, 91% of toluene was degraded after 1 h of irradiation, and this efficiency was about 12 higher than that for pristine QDs under 375 nm. Generally, building the TiO₂/AgInS₂ and TiO₂/SnS exhibited higher photoactivity under 375 nm than the pristine TiO₂ and QDs which suggests a synergistic effect between QDs and TiO₂ matrix. [ABSTRACT FROM AUTHOR]