Titanium-Doped Solid Core-Mesoporous Shell Silica Particles: Synthesis and Catalytic Properties in Selective Oxidation Reactions

Abstract

AbstractNear monodisperse spherical particles composed of a nonporous silica core covered by a Ti-doped hexagonally arranged mesoporous silica shell, Ti-SCMS, as well as spherical submicron-size particles of Ti-MCM-41, have been synthesized for the first time and characterized by elemental analysis, N 2 adsorption, XRD, TEM and DR-UV spectroscopy. The mesoporous Ti,Si-shell has a thickness of about 45 nm and incorporates isolated Ti centers in tetrahedral coordination. Catalytic properties of Ti-SCMS and Ti-MCM-41 have been studied in selective oxidation of three representative bulky organic substrates, 2,3,6-trimethylphenol, methyl phenyl sulfide and caryophyllene, with aqueous H 2 O 2 in MeCN medium. Ti-SCMS appeared to be more active and selective in the H 2 O 2 -based selective oxidation reactions compared to Ti-MCM-41, thus demonstrating an advantage of conducting a catalytic process in a thin mesoporous Ti,Si-shell.Graphical AbstractNear monodisperse spherical silica particles with a solid inert core covered by a well-ordered mesoporous shell, containing site-isolated Ti centers, have been synthesized, characterised and found to be highly active in selective oxidations with H 2 O 2 .[IMAGE]