Direct synthesis of nanostructural and nanospherical silica using induction jet levitation: synthesis, design and catalytic application

Abstract

For the synthesis of porous sorbents based on silicon dioxide, the method of induction flow levitation was used for the first time, which makes it possible to carry out the direct synthesis of various types of silica in a continuous mode with high productivity. Induction levitation of silicon was achieved by applying two-stage heating, since the conductivity of semiconductors increases exponentially with increasing temperature. The developed method of synthesis made it possible to evaporate atoms from the silicon sample, which were stripped from the surface by an argon flow with the formation of atomic vapor. All obtained samples were carefully characterized by various physicochemical methods. On the basis of the obtained silicas, catalytic systems based on ionic liquids were synthesized, which showed high catalytic activity in the trichlorosilane disproportionation reaction, the main reaction of the ‘union-carbide’ process for the production of poly- and monocrystalline silicon. The developed method makes it possible to obtain nanospherical and nanostructured silicon dioxide with a capacity of up to 100 g/h in a continuous noncontact mode, significantly exceeding the previously developed methods for the synthesis of silica and is a promising method for the production of catalyst supports with high surface areas and functionalization possibilities by organic and inorganic active sites for heterogeneous catalysis.