Synthesis and catalytic properties of sulfonic acid-functionalized monodispersed mesoporous silica spheres

Synthesis of amino group functionalized monodispersed mesoporous silica nanospheres using anionic surfactant

“…The standard deviation was calculated from the diameters of randomly chosen 50 particles observed in a TEM image. The particles with a standard deviation of less than 10% have been considered to be monodisperse [30]. The microscopic features of all samples were observed by SEM (JEOL JSM-7401F).…”

“…Various functionalized mesoporous silica nanospheres have been synthesized by post-synthesis and co-condensation methods using cationic surfactant [18,[27][28][29][30][31][32]. Typically, for mesoporous silica nanospheres, amino group functionalization has been obtained by co-condensation of 3-aminopropyltrimethoxysilane with silica source [26][27][28]; carboxylic group functionalization has been achieved by introducing 3-cyanopropyl-trimethoxysilane in the synthesis system and subsequent hydrolysis with sulfuric acid [29]; and the sulfonic acid functionalization has been attained by a similar two-step process involving co-condensation and subsequent oxidation of 3-mercaptopropyltrimethoxysilane [30]. Recently, Garcia-Bennett et al found that mesoporous nanoparticles with AMS-8 type structure (space group Fd-3m) could be prepared by adding nonionic surfactant P123 in the synthesis gel above its cloud point, which disperses the nucleation sites and limits the diffusion of silicate oligomers in the synthesis of the nanospheres [32].…”

Propylsulfonic acid functionalized mesoporous silica catalysts for esterification of fatty acids

“…In order to optimize the performance of mesoporous silica in important applications, such as catalysis, separation, adsorption and ion-exchange, new synthetic chemicals have been introduced into their composition to alter their properties [1]. Recently, several new types of large-pore mesoporous silica materials, such as SBA-15, have been reported [2,3], where the material's structure and texture, especially the acidic sites, affect its catalytic properties [4].…”

Visible light-sensitive mesoporous N-doped Ta2O5 spheres: synthesis and photocatalytic activity for hydrogen evolution and CO2 reduction

“…[10][11][12] Control of particle size and morphology (porosity) is required to improve the photocatalytic activity of N-Ta 2 O 5 , as demonstrated for mesoporous silica or TiO 2 catalysts. [13][14][15][16] Smaller particles of semiconductor nanocrystals improve the photocatalytic activity, because the diffusion distance of photoexcited electrons to active surface sites of the semiconductor is shortened, while the larger surface area of the porous structure can significantly enhance the access of reactants to the catalytically active sites on the internal surfaces. Furthermore, submicron-sized spherical morphology composed of nanocrystals (ca.…”