Photocatalytic Properties of Mechanochemically Synthesized Nanocrystalline $ZnAl_2O_4$ and CdSe

Nanocrystalline powders of $ZnAl_2O_4$ and CdSe were prepared via mechanochemical synthesis. Powder slurries were coated as thin films on $SiO_2$ thin layer chromatography (TLC) sheet by capillary method. The photocatalytic activity of the film coating was tested in a self-made gas-phase flat-plate continuous-flow photocatalytic reactor with toluene as model air contaminant. The tested nanocrystalline $ZnAl_2O_4$ turned out to be poor oxidation photocatalyst under UV irradiation. CdSe displays considerable photocatalytic activity under visible light, where $TiO_2$ is inactive. The nonconventional one-step mechanochemical route to $ZnAl_2O_4$ and CdSe synthesis offers several advantages compared to traditional processing routes, including low-temperature solid state reactions at ambient temperature, absence of organic templates contamination and low expenses.