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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