Synthesis of monodisperse spherical silica particles with solid core and mesoporous shell: mesopore channels perpendicular to the surface

Abstract

Both particle monodispersity and mesopore orientation have been considered in this work. Monodisperse spherical silica particles with a solid core and a mesoporous shell featuring mesopore channels perpendicular to the core surface were synthesized for the first time by adopting silica particles as the core component and by employing C n -TAB (n = 12, 14, 16, 18), the structure-directing agent for the mesoporous shell. Micelles on the surface of the silica particles are formed from the electrostatic interaction between the partially negatively charged silica particles and the positively charged surfactant molecules under basic conditions. The particles synthesized in this work have a uniformly coated thin mesoporous shell of about 28-61 nm in thickness over the silica core and possess a surface area of ca. 370-500 m 2 g 21 , pore volume of ca. 0.2-0.35 cc g 21 , and narrow pore size distribution.

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

“…Typical textural and structural characteristics of Ti-SCMS are given in Table 1 along with Ti content determined by elemental analysis. The values of the specific surface area and pore volume of the Ti-SCMS material are close to the corresponding characterictics of the pure siliceous material reported ealier [11]. Hence, the results acquired from N 2 adsorption measurements together with the XRD data strongly support the formation of a material of the MCM-41 type with hexagonal arrangement of mesopores-channels.…”

“…The thickness of the shell was estimated to be 45 nm, while the average particle diameter equals to 510 nm. The thickness of the mesoporous shell and the avarage particle diameter of Ti-SCMS are in good agreement with the respective parameters of the Ti-free coreshell particles [11].…”

“…The synthesis of Ti-SCMS was carried out by a two-step one-pot route adapting the procedure described for Ti-free core-shell silica particles [11]. To prepare near monodisperse solid beads, TEOS was added to the solution containing ethanol and aqueous ammonia and stirred for 6 h at room temperature.…”

“…Recently, these two approaches were combined to prepare monodisperse hybrid spherical SiO 2 particles consisting of a solid nonporous core covered by a wellordered mesoporous silica shell with a uniform thickness [11]. Such a well-organized mesoporous structure, having not only a regular diameter of pores-channels but also a uniform, easily tuned length of the channels, cannot be accomplished using traditional MCM preparation routes.…”

Fe modified mesoporous hollow carbon spheres for selective oxidation of ethylbenzene

“…1, this method utilized the SiO 2 @Fe-mSiO 2 as the suitable hard template to provide active sites for pyrolysis simultaneous deposition of PS. Firstly, SiO 2 @mSiO 2 was produced by adopting silica nanoparticles as the core and the structure-directing agent for the mesoporous silica shell [23]. Subsequently, Fe(NO 3 ) 3 ·9H 2 O was impregnated in the mesopores of the SiO 2 @mSiO 2 .…”