STUDY OF PROCESSES OF MODIFICATION OF THE SURFACE OF TiO2 NANOPOWDER UNDER THE ACTION OF HYDROGEN PEROXIDE.

Abstract

Using the methods of X-ray photoelectron spectroscopy, nuclear magnetic resonance, IR-spectroscopy and atomic force microscopy, the electronic structure and surface morpho­logy of TiO2nanopowders synthesized by the EEW method were investigated. The samples were exa­mined before and after their modification with hydrogenperoxide. This information is relevant for the development of methods of self-doping of oxide matrices with anexcess of oxygen in order to create active centers on the surface in the form of peroxide groups, which leads to the appearance of TiO2 photo activities in the visible light region. Taking into account the possibility of detection of both reducing and oxidizing functions by hydrogenperoxide, the effect of hydrogen peroxide on the TiO2 surface under different modes of modification was investigated. The influence of the degree of hydration (Оlat./Оads.) of the original oxide matrix on the binding energy and the relative changes in the contributions of different types of oxygen peroxogroups of hydrogenperoxide-modified TiO2 were determined using XPS. In the paper, the corresponding O1s spectra were obtained and the E energies and integral intensities of the corresponding components were determined, the value of the Оlat./Оadsratio for unmodified and modified samples was given. It was established that for a series of TiO2 samples, the ratio of integral intensities of peroxo groups in the O1s spectra is preserved. For the first time, the O1s spectrum of titanium peroxide was inter pretedin terms of the O-O form of oxygen. The mechanism of action of hydrogen peroxideon the metal oxide matrix is proposed, which is determined by the degree of blocking of themain O2centers of the oxide matrix by the OH groups present in it, which leads to a change in the direction of redox transformations.