Structural propertis of micropowders composition SiO2:CuO & SiO2:Cu° prepared by sol-gel method

Abstract

The aim of the research was to obtain and study the functional characteristics of composite materials of the composition SiO2, SiO2:CuO and SiO2:Cu°, synthesized on the basis of Aerosil A-300. The basis for obtaining micropowders from pyrogenic silica was an aqueous dispersion of aerosil containing copper nitrate with a concentration (in molar percent) SiO2:Cu (NO3)2×3H2O = 1:0.25; 1:0.40 and 1:0.5. The aqueous dispersion (sol) of the specified composition was subjected to successive drying and annealing in air to T = 800 ºС (holding time was 1 h). The micro-powder formed as a result of such heat treatment had a phase composition of SiO2:CuO. Further annealing of such composite micro-powders in a hydrogen atmosphere (at Т = 800 ºС, holding time - 1 h) made it possible to transform bivalent copper oxide Cu (II) into the state of reduced copper (Cuº).The phase transformations of copper nitrate into its oxide (II) or reduced copper (under the action of thermal treatment of micropowders in an appropriate gas environment) were studied using the method of X-ray phase analysis. The morphology of the structure of the synthesized xerogels was studied by scanning electron microscopy. The processing of the obtained SEM images was carried out using the Gwyddion program (techniques were used to create an inverted "mask" for the surface of the sample under study). The elemental composition of the synthesized micropowders was determined by the (EDX) method. Based on the data obtained and studies carried out by other authors for materials of this kind, assumptions were made about the possibility of using synthesized powders of SiO2 xerogels containing micro- and nanoparticles of reduced metals (as well as metal oxides) as effective biologically active substances with a wide range medical purposes, as well as construction materials used to create microsensors with a selective sensitivity zone.