ZnO@CuO derived from Cu-BTC for efficient UV-induced photocatalytic applications

ZnO@CuO nanocatalyst was prepared via CuO formation from Cu-BTC (Copper benzene-1,3,5-tricarboxylate) support and simultaneous in-situ buildup of ZnO nanoparticles. X-ray diffraction (XRD) results showed formation of ZnO and CuO peaks and disapperance of Cu-BTC peaks. Micro and mesopores generation were noticed in surface area (BET) measurements. Scanning electron microscopy (SEM) images revelaed octahedrally shaped aggregates inherited from Cu-BTC and spherical nanoparticles. Existence of ZnO and CuO were confimed by mapping images (EDX), Raman spectra and X-ray photoelectron spectra (XPS). The characteristic edge of ZnO was observable in the UV-vis diffuse reflectance (UV-vis DRS) absorption profile of ZnO@CuO. ZnO@CuO's dark absorption capability and photocatalytic of activity under UV irradiation were explored in terms of methyl orange (MO) and methylene blue (MB) probe molecules. ZnO@CuO was also examined under 40%, 67% and 84% relative humidity (RH) conditions. In humidified ZnO@CuO structural features were preserved. ZnO@CuO showed the highest dark adsorption capacity for MO, whereas ZnO@CuO (84%) exhibited the stongest adsorption for MB. The highest rates were obtained in the presence of ZnO@CuO (84%) for both MO and MB, following pseudo-first order kinetics and Langmuir-Hinshelwood model. Stabilities of ZnO@CuO and ZnO@CuO (84%) were also controlled.