Preparation And Photocatalytic Performance Of Spinel Type Composite Oxide

Spinel type composite oxide is a new kind of semiconductor materials, with unique crystal structure, adjustable component, photochemical stability and etc, which has attracted many scholars’ attention. It has been widely applied in electronics, magnetics, optics, sensing, semiconductor, catalysis and so on. Recently, Spinel type composite oxide photocatalyst applied in the degradation of organic dyes area has become a focus of research. In this paper, the promising Zn Ga2O4 with high activity in ultraviolet region and Cu Cr2O4 which is highly effective in visible light were selected as photocatalysts, moreover, both their modification and photocatalytic properties were studied. The main contents of this paper are as follows:The cubic Zn1-xCoxGa2O4 photocatalysts were synthesized by hydrothermal method. The samples were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), UV-Vis diffusion reflectance spectra(DRS) and X-ray photoelectron spectroscope(XPS). The results indicate that the Co is successfully incorporated into the Zn Ga2O4 lattice, and Co doping can influence the crystalline morphology and narrow the band gap of photocatalysts. The experiments of photocatalytic degradation of Rh B results demonstrate that Co doping can greatly enhance the photocatalytic activity of Zn1-xCoxGa2O4, and the Cu0.95Ni0.05Cr2O4 sample has the optimal photocatalytic activity. Moreover, the photocatalytic degradation of Rh B follows a pseudo-first-order reaction. The mechanism of Co doping enhanced Zn Ga2O4 samples’ photocatalytic activity is also discussed.Cu Cr2O4 nanoparticles with cubic-like morphology were prepared via hydrothermal synthesis method without template. The Cu Cr2O4 samples were characterized by TG-DSC, XRD, TEM, XPS, DRS and Zeta potentials, respectively. The results indicated that cubic-like Cu Cr2O4 could be successfully synthesized by calcining the precursor at 600 °C, and the calcination temperature greatly influenced the morphology and optical performance of Cu Cr2O4. The p H at the point of zero charge(p Hpzc) of the Cu Cr2O4 calcined at 600 °C was about 4.52. The photocatalytic activity of Cu Cr2O4 was evaluated for degradation of rhodamine B(Rh B), methylene blue(MB), and methyl orange(MO) and the effects of the calcination temperature, dosage of photocatalyst, etc, on photocatalytic activity were studied in detail. The photocatalytic results revealed that the Cu Cr2O4 photocatalyst was of high activity for degradation of Rh B(96.8 %) and MB(99.5 %), but very low activity for degradation of MO(14%). The Cu Cr2O4 sample calcined at 600 °C possesses the best photocatalytic activity, and the optimal dosage of the Cu Cr2O4 photocatalyst is 0.4 g/L.A series of Ni doped Cu1-xNixCr2O4 photocatalysts were prepared by hydrothermal synthesis method. The crystal structure, morphology, specific surface area, chemical composition and optical absorption properties of the photocatalysts were characterized by using XRD, SEM, TEM, BET, XPS and DRS techniques. The characterization results demonstrate that the Ni is successfully incorporated into the Cu Cr2O4 crystal lattice, and Ni doping can influence the photocatalysts’ morphology and visible light absorption ability. The photocatalytic degradation experiments’ results indicate that Ni doping can greatly strengthen the catalytic activity of Cu Cr2O4 photocatalysts, and the Cu0.95Ni0.05Cr2O4 sample has the optimal visible light catalytic activity, and the degradation rate of MB is 98% after irradiation 40 min. Moreover, the mechanism of Ni doping enhanced Cu Cr2O4 samples’ photocatalytic activity is discussed.