Huilian Liu

Structure and magnetic properties of Fe-doped ZnO prepared by the sol–gel method

Zn(0.97)Fe(0.03)O nanoparticles were synthesized by the sol-gel method. X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis revealed that the samples had pure ZnO wurtzite structure and Fe ions were well incorporated into the ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS) showed that both Fe(2+) and Fe(3+) existed in Zn(0.97)Fe(0.03)O. The result of x-ray absorption near-edge structure (XANES) further testified that Fe ions took the place of Zn sites in our samples. Magnetic measurements indicated that Zn(0.97)Fe(0.03)O was ferromagnetic at room temperature.

Mesoporous TiO2 coated ZnFe2O4 nanocomposite loading on activated fly ash cenosphere for visible light photocatalysis

Several activated fly ash cenosphere (AFAC) supporting TiO2 coated ZnFe2O4 (TiO2/ZnFe2O4/AFAC) photocatalysts were prepared by sol–gel and hydrothermal methods. These photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (UV-DRS) and nitrogen adsorption analyses for Brunauer–Emmett–Teller (BET) specific surface area measurements. We found that the main components of spherical AFAC were mullite (Al6Si2O13) and SiO2; the crystallite size of the TiO2/ZnFe2O4 nanocomposite was less than 10 nm and its specific surface area was 162.18 m2 g−1. The TiO2/ZnFe2O4 nanocomposite had a band-gap of 2.56 eV, which would photodegrade 95% of rhodamine B (RhB) under visible light within 75 min. When hybridized with 0.02 g AFAC, the TiO2/ZnFe2O4/0.02 g AFAC photocatalyst with a band-gap of 2.50 eV could remove 97.1% of RhB and be reused three consecutive times with minor decrease in photocatalytic performance. However, the photocatalytic performance decreased to 91.0% on increasing the dosage of AFAC to 0.30 g. The mesoporous structure of all the photocatalysts and the strong adsorption ability of AFAC accounted for the notable performance.

Comparative studies of the structural and magnetic properties in Cu, Co codoped ZnO multilayer films sputtered on different substrates

Abstract The Zn0.959Cu0.023Co0.018O multilayer films on silicon and polystyrene particles array were prepared using RF magnetron sputtering technique. The influences of the substrate on structural and magnetic properties of Cu, Co codoped ZnO multilayer films were investigated by X-ray diffraction, Scanning electron microscope, X-ray photoelectron spectroscopy, and vibrating sample magnetometer. The results indicated that all the samples were the wurtzite structure with hexagonal shapes of ZnO holding different degree of preferred orientation, the Cu2+, Cu+ and the Co3+, Co2+ ions would uniformly substitute into the Zn2+ sites of ZnO lattice in the samples sputtered on the different substrates. All the samples showed room temperature ferromagnetism, the saturation magnetization and the coercivity of the samples sputtered on the different substrates changed due to the chemical states of the Cu and anisotropy energy of the samples.

A study of the potential barrier at the Σ13 (510) tilt boundary of strontium titanate using electron holography and dynamic simulation

The phase shift of the exit electron wave function at the Σ13 (510) tilt boundary of strontium titanate (SrTiO3) bicrystals was detected by electron holography. The results showed that there is a phase shift peak with a magnitude of ~0.3 rad at the centre of this grain boundary. Such a phase shift suggests that the potential barrier of ~3 V induced at the boundary core due to the interruption of the periodic potential of the crystal may be one of the intrinsic properties of grain boundary phenomena. Based on an electron dynamic diffraction, the phase of the exit electron wave function was simulated using a relaxed Σ13 (510) tilt boundary supercell with various occupancies of the atomic columns at the interface core. Coincidence of the measured and calculated results was achieved when the atomic columns are only half-occupied at the interface.

XPS and Raman study of the active-sites on molybdenum disulfide nanopetals for photocatalytic removal of rhodamine B and doxycycline hydrochlride

Molybdenum disulfide (MoS2) nanopetals were successfully synthesized by hydrothermal method (sample without sintering) and then sintered at different temperature (sintered samples). The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen (N2) adsorption analyses for Brunauer–Emmett–Teller (BET) specific surface area measurements, X-ray photoelectron spectrum (XPS) and Raman spectrum. XRD pattern indicated that the samples can be indexed to hexagonal phase 2H-MoS2. SEM and TEM images showed that the sintered MoS2 nanopetals had sizes ranging from 150 to 300 nm with almost the same morphology. The pore structure and surface area were nearly the same for the three sintered MoS2 nanopetals. Interestingly, XPS and Raman spectra implied that there was a few 1T-phase in the MoS2 nanopetals which enhanced the photocatalytic performance greatly when sintered at low temperature.