Nanocomposites and nanomaterials

Influence of nitrogen and metal ions co-doping on optical, structural and surface properties of modified titania films
Linnik O.
Chuiko Institute of Surface Chemistry of the NAS of Ukraine. General Naumov Str.,17, Kyiv-03680, Ukraine. 
E-mail: okslinnik@yahoo.co.uk.

Design of modified titania is actual research field directed to air purification, surface self-cleaning, and wastewater treatment processes under solar light. Co-doping with nitrogen and metal ions leads to the change in optical, structural and photocatalytic properties of the nanomaterials [1]. 
There are a number of key points needed to be clarify to characterize the behavior of nitrogen doped nanocomposites: the chemical nature and the location of the nitrogen species in the solid. Herein, the effect of metal ions on the type and amount of incorporated nitrogen as well as the optical, structural and surface properties of titania films are presented. 
Co-doped TiO2 films are obtained by sol-gel method where urea, as a nitrogen source, and the different metal ions, such as zinc, iron, zirconium, platinum or ruthenium ions, as a second doping agent, are used. 
As revealed by XRD results, the formation of anatase with the particle size up to 20 nm is detected for most co-doped titania films. However, the anatase crystallization accompanied by Zn2Ti3O8 and brookite formation is noted for N/Zn/TiO2 and N/Pt/TiO2, respectively. The rate of anatase crystallization is shown to be depended on the nature of the doping agents.
The presence of nitrogen and metal ions in titania matrix has an influence on its optical properties as well: the band-gap values are lowered and the absorption in the visible part of spectrum is arisen. 
The different types of nitrogen species incorporated in oxide structure are observed by means of XPS analysis. The substitutional or interstitial nitrogen incorporation can be achieved only in the presence of metal ions having bigger ionic radius than titanium one. 

1.	Linnik O., Shestopal N., Smirnova N, Eremenko A., Korduban O, Kandyba V., Kryshchuk T., Socol G., Stefan N., Popescu-Pelin G., Ristoscu C., Mihailescu I.N. Correlation between electronic structure and photocatalytic properties of non-metal doped TiO2/ZrO2 thin films obtained by pulsed laser deposition method // Vacuum.-2015.-114.-P. 166-171.