Al-doped and pure ZnO thin films elaborated by sol–gel spin coating process for optoelectronic applications

Pure and aluminum-doped zinc oxide thin films were grown by spin coating at room temperature. As a starting material, zinc acetate was used. The dopant source was aluminum nitrate; the dopant molar ratio was varied between 1 and 10%. Structural analysis reveals that all films consist of single hexagonal wurtzite phase ZnO, and a preferential orientation along c-axis. They have a homogeneous surface. The measurements show that the films are nanostructured. The transmittance is greater than 75% in the visible region. The band gap energy decreases with the addition of dopant (Al) in prepared thin films and the resistivity decreases significantly.     

Total Oxidation of Dichloromethane Over Metal Oxide Catalysts

Three different transition metals (V, Mn and Cu) supported on TiO₂, MgO and CeO₂, were investigated for their performances in dichloromethane oxidation (500 ppm, 704,867 h^?1) in moist conditions as a model reaction for the destruction of chlorinated volatile organic compounds. The catalysts were prepared by sol–gel method followed by wet impregnation of V, Mn or Cu precursors. The activities were evaluated in the temperature range from 100 to 500 °C with 5 °C min^?1 temperature rise. The orders of activity and selectivity to HCl of the catalysts is CuTi > VMg > CuCe > CuMg. A correlation between acidic properties of support and performances was observed as the activity of copper catalysts followed the acidity order of supports.     

Oxygen Storage Capacity of Pt–CeO2 and Pt–Ce0.5Zr0.5O2 Catalysts

Cerium dioxide containing materials have involved much interest in recent years owing to their broad range of applications in various fields. The most important property that makes ceria as an excellent catalytic material is its oxygen storage and release capacity via the ability of ceria to rapidly switch from Ce³⁺ to Ce⁴⁺ under reducing and oxidizing conditions, respectively. Zirconia is incorporated into the ceria matrix as it greatly improves thermal stability and oxygen diffusion through the bulk of the crystallites.