Enhanced UV-Visible photocatalytic activity of Cu-doped ZnO/TiO_2 nanoparticles

摘要

Abstract Cu–ZnO/TiO~(2)nanoparticles were prepared by entrapping copper ions into crystalline matrix of ZnO/TiO~(2)through sol–gel synthesis method. The photocatalyst matrix loaded with different copper concentrations was calcined at 500 and 700 °C. Thermal property, crystalline structure, surface morphology and absorption spectra of Cu–ZnO/TiO~(2)were characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, transmission electron microscope and UV–Vis spectrophotometry. Besides, its specific surface area and band gap energy level were estimated through BET surface area method, Kubelka–Munk model and Planck’s equation. The results revealed that Cu–ZnO/TiO~(2)had a more thermally stable lattice compared to TiO~(2)/ZnO and hence the phase transformation from anatase to rutile is retarded under higher calcination temperature in Cu–ZnO/TiO~(2)lattice. The photoactivity of Cu–ZnO/TiO~(2)was then evaluated through degradation of methyl orange under visible light irradiation. Among different samples, the samples that were calcined at 500 °C exhibited the highest photocactivity compared to those calcined at 700 °C. Cu–ZnO/TiO~(2)with a Cu content of 3 wt% was observed to have the maximum activity, giving C/C~(0)value of 0.03 after 150 min. This value was about 12 and 28.3 times higher than that of ZnO/TiO~(2)and TiO~(2), respectively.