T.N. Myasoedova

Copper-oxide metalorganic nanocomposite: morphological and X-ray spectroscopy studies

Oxidation state, local and electronic structure as well as the surface morphology of a CuOx nanocomposites were investigated. The research is focused on studying the relationships between surface morphology and structure of the inorganic component of the nanocomposites. The physico-chemical mechanisms of change in local and electronic structure, oxidation state and the surface morphology of nanocomposites in the interaction of metal oxide nanoparticles with different types of matrices were determined.

Influence of the surface morphology and structure on the gas-sorption properties of SiO2CuOx nanocomposite materials: X-ray spectroscopy investigations

Thin films of SiO2CuOx nanocomposite materials were synthesized by the sol-gel method upon deposition of solutions containing 1, 3, 5, and 7 wt % Cu. The scanning electron microscopy examination of the surface morphology revealed that a change in the copper concentration in the initial solution has an influence on the size and amount of crater-like pores formed in the amorphous silicon dioxide matrix and on the localization of copper crystallites on the surface of the films. X-ray absorption near-edge structure (XANES) spectroscopy and X-ray photoelectron spectroscopy (XPS) investigations showed that the structure of crystallites is predominantly formed by divalent copper oxide (CuO). However, an increase in the copper concentration in the initial solution leads to a systematic increase in the content of the Cu2O phase. At copper concentrations of 1 and 7 wt %, the surface layers are most likely characterized by the formation of several divalent copper oxides (Cu(OH)2, CuO, CuSiO3), which results in the deterioration of the gas-sensitive characteristics of the material. It was established that the optimum set of parameters (the presence of pores, localization of crystallites, copper phase composition in the crystallites) for the best gas-sensitive characteristics of SiO2CuOx composite films is observed at copper concentrations of 3 and 5 wt % in the initial solution.

CuOX Films for NO2 Detection: Microstructural Characterization

Copper oxides films as promising materials for gas sensors applications were studied. Copper oxide films were deposited onto Si/SiO2 substrates using a citrate sol-gel method with the subsequent temperature treatment at 150-5000C. These films were characterized by means of secondary electron microscopy (SEM) and X-ray-absorption near-edge structure (XANES) spectroscopy. The prepared films were utilized in NO2 sensors. The dependences of the NO2 response on the operating temperature and NO2 concentration (10-200 ppm) were investigated. The maximum NO2 response was achieved for the film annealed at 2500C.