Various types of semiconductor photocatalysts modified by CdTe QDs and Pt NPs for toluene photooxidation in the gas phase under visible light

Highlights: • Novel semiconductors decorated by CdTe QDs and/or Pt NPs were synthesized. • Photodeposition and radiolysis is an effective method to obtaining Pt NPs. • CdTe decorated samples were prepared by absorption of QDs on matrix surface. • KTaO₃/CdTe-Pt_(R) showed highest photocatalytic performance. • The enhanced performance was associated with electron trap mechanism. - Abstract: A novel synthesis process was used to prepare TiO₂ microspheres, TiO₂ P-25, SrTiO₃ and KTaO₃ decorated by CdTe QDs and/or Pt NPs. The effect of semiconductor matrix, presence of CdTe QDs and/or Pt NPs on the semiconductor surface as well as deposition technique of Pt NPs (photodeposition or radiolysis) on the photocatalytic activity were investigated. The as-prepared samples were characterized by X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) with energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), photoluminescence spectrometry (PL), Fourier transform infrared (FT-IR) and Raman spectra, diffuse reflectance spectroscopy (DRS) and BET surface area analysis. The photocatalytic decomposition of toluene in gas phase, activated by light-emitting diodes (LEDs), with the CdTe/Pt nanoparticles-modified TiO₂ microspheres, P25, SrTiO₃ and KTaO₃ semiconductors was investigated under UV–vis and visible irradiation.The results showed that the photoactivity depends on semiconductor matrix. The highest photoactivity under Vis light was observed for KTaO₃/CdTe-Pt_(R) sample (56% of toluene was decompose after 30 min of irradiation). The efficiency of the most active sample was 3 times higher than result for P25 and two times higher than for unmodified KTaO₃.