Katok K. Immobilization of metal nanoparticles in surface layer of mesoporous silica matrices

The dissertation is devoted to elaboration of methods of synthesis of metal-containing silicas with supported nanoparticles of gold, silver and metals from iron subgroup (Co, Ni and Fe) and studying of their properties. Using silicon hydride groups grafted to the silica surface and their reducing properties, methods of synthesis of silicas with immobilized gold and silver nanoparticles have been developed. It is possible to regulate sizes of the formed metal particles varying concentration of metal salt taken for reduction, time of reduction and type of silica matrices. Silicas with supported gold nanoparticles were found to have high enough activity in the reaction of hydrogen oxidation with molecular oxygen. The reproducible method formation of stable colloids of nanosized silver covered with silica shell in the moment of simultaneous reduction of metal and formation of silica in result of hydrolysis and condensation of triethoxysilane was developed. Efficient methods have been developed for producing of metalcontaining silicas using chemical modification of mesoporous silica with Ni(acac)2, Co(acac)2, Fe(acac)2 and following formation of metal nanoparticles in the reducing atmosphere (H2, C2H2). Availability of metal nanoparticles on the silica surface initiates a growth of carbon nanostructures depending on conditions of acetylene pyrolysis.