The effects of bifunctional linker and reflux time on the surface properties and photocatalytic activity of CdTe quantum dots decorated KTaO3 composite photocatalysts

•CdTe quantum dots were loaded onto KTaO3 cubes using MPA or TGA as linker molecules.•Shorter chain length of TGA as compared with MPA promotes photocatalytic activity.•Fluorescence quenching of nanodots indicates electron transfer from CdTe to KTaO3.•The size of CdTe quantum dots affects Vis driven photoactivity of CdTe-KTaO3.•2.04 nm CdTe dots are favorable for photoactivity of the TGA-CdTe-KTaO3 composite.

Novel CdTe-KTaO3 composite photocatalysts were successfully synthesized by using thioglycolic acid (TGA) or 3-mercaptopropionic acid (MPA) as linker molecules which facilitated attachment of CdTe quantum dots to the surface of KTaO3 nanocubes. The as-prepared photocatalysts were characterized by UV-vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) specific surface area, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) emission spectroscopy. The obtained CdTe-decorated KTaO3 composites showed greatly improved photocatalytic performance for degradation of toluene in the gas phase under LEDs light irradiation (λmax = 415 nm) over pristine KTaO3. TGA-functionalized CdTe-KTaO3 composites exhibited higher photocatalytic activity as compared with MPA-capped CdTe-KTaO3 hybrids which can be ascribed to the shorter chain length of TGA molecule as compared with MPA linker and therefore faster electron transfer from TGA-CdTe nanodots to perovskite-type potassium tantalate. The significance of quantum size effect of CdTe QDs for enhancing photocatalytic performance of CdTeQDs-decorated KTaO3 was also discussed.

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