Zhaorui Zou

Bio: Zhaorui Zou is an academic researcher from Henan Normal University. The author has contributed to research in topics: Doping & Ferromagnetic material properties. The author has an hindex of 3, co-authored 6 publications receiving 26 citations. Previous affiliations of Zhaorui Zou include Wuhan University.

Magnetic properties of Mo–N co-doped TiO2 anatase nanotubes films

Abstract: In this paper, the un-doped, Mo doped, N doped and Mo–N co-doped TiO2 nanotubes (TNTs) films were prepared by a two-step anodic oxidation method. The paper mainly investigated the origin of room temperature (RT) magnetic properties of all the samples. X-ray diffraction studies showed that the impurity of magnetic Mo atoms or N atoms were doped into anatase TiO2 lattices. It is revealed by the results of X-ray photoelectron spectroscopy and photoluminescence spectra that oxygen vacancies (Vos) exist. For all the samples the values of the saturation magnetizations (Ms) are in the order of Mo–N co-doped TiO2 > Mo-doped TiO2 > N-doped TiO2 > un-doped TiO2. Thus, the the Mo–N co-doped film achieved the highest RT Ms. The enhancement of the Ms origins from the cooperationg of the doping Vo, Mo and N. This progress provides some clues for the increase the saturation magnetization in TiO2-based dilute magnetic semiconductors at RT. The experiment results indicate that the Vos play a crucial role in RT ferromagnetic properties for TNTs films.

Improved Performance of NbOx Resistive Switching Memory by In-Situ N Doping

Abstract: Valence change memory (VCM) attracts numerous attention in memory applications, due to its high stability and low energy consumption. However, owing to the low on/off ratio of VCM, increasing the difficulty of information identification hinders the development of memory applications. We prepared N-doped NbOx:N films (thickness = approximately 15 nm) by pulsed laser deposition at 200 °C. N-doping significantly improved the on/off ratio, retention time, and stability of the Pt/NbOx:N/Pt devices, thus improving the stability of data storage. The Pt/NbOx:N/Pt devices also achieved lower and centralized switching voltage distribution. The improved performance was mainly attributed to the formation of oxygen vacancy (VO) + 2N clusters, which greatly reduced the ionic conductivity and total energy of the system, thus increasing the on/off ratio and stability. Moreover, because of the presence of Vo + 2N clusters, the conductive filaments grew in more localized directions, which led to a concentrated distribution of SET and RESET voltages. Thus, in situ N-doping is a novel and effective approach to optimize device performances for better information storage and logic circuit applications.

Oxygen Defect-Mediated Magnetism in Fe-C Codoped TiO2

Abstract: The magnetic properties of the C doped and C-Fe codoped TiO2 films fabricated by sol-gel and spin coating have been investigated combining experiments and first-principles calculations. All the samples exhibit the anatase crystal phase and the room temperature ferromagnetism. The values of the saturation magnetizations are in the order of Fe-C codoped TiO2 > Fe-C codoped TiO2 (annealed in O2) > C doped TiO2 > C doped TiO2 (annealed in O2). The calculated net moment values are in the order of Fe-C codoped TiO2 > C doped TiO2 with oxygen vacancies existing, in accord with the experimental results. The hybridization of Fe 3d, C 2p, and O 2p (nearest to the Fe defect) led to the spin split of Fe 3d, C 2p, and O 2p which contributed to the ferromagnetism.

Modified Titanium Dioxide for Photocatalytic Applications

Abstract: Titanium dioxide (TiO 2 ) has been widely used as a photocatalyst in many environmental and energy applications due to its efficient photoactivity, high stability, low cost, and safety to the environment and humans. However, its large band gap energy, ca. 3.2 eV limits its absorption of solar radiation to the UV light range which accounts for only about 5% of the solar spectrum. Furthermore, the photocatalytic activity of TiO 2 is also limited by the rapid recombination of the photogenerated electron-hole pairs. When used in water treatment applications, TiO 2 has a poor affinity toward organic pollutants, especially hydrophobic organic pollutants. Several strategies have been employed to reduce its band gap energy, its electron-hole recombination rates as well as enhance its absorption of organic pollutants. In this chapter, we review some of the most recent works that have employed the doping, decoration, and structural modification of TiO 2 particles for applications in photocatalysis. Additionally, we discuss the effectiveness of these dopants and/or modifiers in enhancing TiO 2 photoactivity as well as some perspective on the future of TiO 2 photocatalysis.

Application of Reverse Micelle Sol–Gel Synthesis for Bulk Doping and Heteroatoms Surface Enrichment in Mo-Doped TiO2 Nanoparticles

Abstract: TiO₂ nanoparticles containing 0.0, 1.0, 5.0, and 10.0 wt.% Mo were prepared by a reverse micelle template assisted sol⁻gel method allowing the dispersion of Mo atoms in the TiO₂ matrix. Their textural and surface properties were characterized by means of X-ray powder diffraction, micro-Raman spectroscopy, N₂ adsorption/desorption isotherms at -196 °C, energy dispersive X-ray analysis coupled to field emission scanning electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance UV⁻Vis spectroscopy, and ζ-potential measurement. The photocatalytic degradation of Rhodamine B (under visible light and low irradiance) in water was used as a test reaction as well. The ensemble of the obtained experimental results was analyzed in order to discover the actual state of Mo in the final materials, showing the occurrence of both bulk doping and Mo surface species, with progressive segregation of MoOx species occurring only at a higher Mo content.