Projects

project RFFR 09-03-00250_a

Synthesis of nanocrystalline ferrites 3d elements and their interaction with the gas phase 

   The project aims to obtain a number of ferrites 3d elements M^IIFe₂O₄ (M^II = Mn, Fe, Co, Ni, Cu, Zn) with high surface area and nanometer crystallite size for selective chemical sensors. The catalytic and sensory properties of ferrite spinel structure shows dependence on the nature of the cation M^II to surface chemical properties: strength and concentration of acid sites and redox ability. Materials are semiconductors with high sensitivity of conductivity to the surface at temperatures of 50 - 300ºC . Nature of adsorption sites on the surface of nanocrystalline ferrites studied by temperature-programmed desorption (TPD ) and reduction ( TPR ) using probe molecules : H₂, NH₃, CO and pyridine. The specific surface area and pore size distribution were determined by low temperature nitrogen adsorbtion . Effect of crystallite size and the nature of chemisorbed molecules on the electronic state of the cations studied by X-ray photoelectron spectroscopy.