Hui-Jing Zhou

Anionic surfactant-templated mesoporous silica (AMS) nano-spheres with radially oriented mesopores.

Mesoporous silica nano-spheres with pore size larger than 3 nm were synthesized using an anionic surfactant as the template. These nano-spheres possess centrosymmetric radial mesopores (emanating from the spherical center to the exterior surface) and form stable suspension. The spherical size and mesostructure can be finely tuned by changing the pH value of the synthetic system in the range of 8.8 to 6.4. In addition, when the pH value was decreased to 5.8, instead of spheres, anisotropic morphologies such as elliptical, peanutlike and trifurcate particles were obtained, exhibiting core/shell structure due to the different orientations of the mesopores in the core and the shell of the particles. It is proposed that the evolution of the morphologies and mesostructures of the products templated by anionic surfactants strongly depend on the pH value of the synthetic system.

Polyelectrolyte–Surfactant Complex as a Template for the Synthesis of Zeolites with Intracrystalline Mesopores

Mesoporous zeolite silicalite-1 and Al-ZSM-5 with intracrystalline mesopores were synthesized with polyelectrolyte-surfactant complex as the template. Complex colloids were first formed by self-assembly of the anionic polymer poly(acrylic acid) (PAA) and the cationic surfactant cetyltrimethylammonium bromide (CTAB) in basic solution. During the synthesis procedure, upon the addition of the silica source, microporous template (tetrapropylammonium hydroxide), and NaCl, these PAA/CTA complex colloids underwent dissociation and gave rise to the formation of hollow silica spheres with mesoporous shells templated by CTAB micelles and PAA domains as the core. Under hydrothermal treatment, the hollow silica spheres gradually merged together to form larger particles with the PAA domains embedded as the space occupant, which acted as a template for intracrystalline mesopores during the crystallization of the zeolite framework. Amphiphilic organosilane was used to enhance the connection between the PAA domain and the silica phase during the synthesis. After calcination, single crystal-like zeolite particles with intracrystalline mesopores of about 5-20 nm were obtained, as characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N(2) adsorption measurements. With the addition of an aluminum source in the synthesis, mesoporous zeolite Al-ZSM-5 with intracrystalline mesopores was also synthesized, and enhanced catalytic property was observed with mesoporous Al-ZSM-5 in acetalization of cyclohexanone with methanol.

Facile fabrication of noble metal nanoparticles encapsulated in hollow silica with radially oriented mesopores: multiple roles of the N-lauroylsarcosine sodium surfactant

A facile one-pot method was reported to fabricate noble metal nanoparticles encapsulated in silica hollow nanospheres with radially oriented mesopores, and the anionic amino acid surfactant, N-lauroylsarcosine sodium, played multiple roles: reducing agent, stabilizer, emulsion droplets and mesopore template.

Facile synthesis of functional bismuth-amino acid coordination polymer nano-structures.

Bismuth-asparagine coordination polymer nanostructures with diverse morphologies were fabricated by a facile aqueous bottom-up coordination-based self-assembly approach, and they exhibited unique properties in catalysis and biological aspects.

Multi-amine-functionalized cubic Fdm mesoporous silica by an anionic surfactant templating route

Ordered multi-amine functionalized mesoporous silica with a 3D cubic Fdm mesostructure was synthesized with anionic surfactant N-lauroylsarcosine sodium (Sar-Na) as a template, and [3-(2-aminoethyl)-aminopropyl]trimethoxysilane (DAPS) or 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (TAPS) as co-structure directing agents (CSDAs). To our knowledge, this is the first time the use of DAPS and TAPS as CSDAs in an anionic surfactant templated system have been reported. Using DAPS and TAPS as the CSDA favors the formation of a 3D cubic mesocaged solid with Fdm symmetry, while with 3-aminopropyltriethoxysilane (APS) as the CSDA, only the p6mm mesoporous phase was formed. The geometrical change of the CSDA resulted in a change of the surfactant packing parameter, leading to the change of the silica mesophase from 2D-hexagonal p6mm to 3D cubic Fdm symmetry. After extraction of the templates, multi-amine-functionalized cubic Fdm mesoporous silicas were obtained. The multi-amine functionlized mesoporous silicas exhibit excellent properties in adsorption and removal of heavy metal ions in solution as well as the support of noble metal nanoparticles.

Facile fabrication of hierarchically nanoporous SBA-1 nanoparticles

Mesoporous silica nanoparticles are drawing increasing attention in biomedical applications. In this work, hierarchically nanoporous SBA-1 single-crystal-like nanoparticles, with a size of 50–300 nm, were synthesized using a cationic surfactant and anionic polymer poly(acrylic acid) (PAA) mesomorphous complexes as a template. The obtained mesoporous silica nanoparticles showed a well ordered cubic Pmn mesostructure, large pore volume and high BET surface area. The materials possess biomodal nanopores corresponding to well-ordered mesopores and secondary interstitial nanopores.

Synthesis of silica nanostructures using synthetic block copolypeptide

Nanoporous silica was synthesized by using synthetic block copolypeptide Phe 20 -b-PBLG 50 as a template under ambient conditions. Anilino-methyl triethoxy silane (AMTS) was used as an intermedium to interact with block copolypeptide Phe 20 -b-PBLG 50 through π-π interaction between the phenyl groups of block copolypeptide and AMTS. Meanwhile, AMTS co-condenses together with tetraethyl orthosilicate (TEOS) after hydrolysis. The structure of complex vesicles due to the self-assembly of block copolypeptide in the organic solvent was immobilized and transcribed by the formation of silica. The formation of micropores could be ascribed to the secondary structure of block copolypeptide and small molecular amine. Our results suggest a new avenue to synthesize porous oxide materials with novel interior structures with the aid of copolypeptide self-assembly under ambient conditions.

Hierarchically Nano-structured In2S3 Hollow Microspheres Synthesized Using Amino Acids as Crystal Growth Modifiers

Hierarchically nano-structured In2S3 hollow microspheres were synthesized by a hydrothermal method and the hollowing effect was attributed to an Ostwald ripening process. Using different amino acids as crystal growth modifiers, In2S3 with different surface morphologies, such as raspberry-like, urchin-like, and flower-like hollow microspheres, were selectively fabricated. The shells of the microspheres were composed of nanosized particles or nanoflakes of In2S3.These results demonstrate that amino acids with different functional groups, such as -NH2, -COOH, and -SH, can induce the formation of different indium sulfide nanostructures. A blue shifted UV band in the UV-Vis spectrum as well as a strong emission at ca 385 nm and a weak emission at ca 364 nm in the photoluminescence (PL) spectrum of In2S3 hollow microspheres indicate strong quantum confinement because of the presence of nanocrystalline particles. Using different amino acids as crystal growth modifiers, microspheres with different surface morphologies were fabricated. These results demonstrate that amino acids with different functional groups can induce the formation of different indium sulfide nanostructures.