Zile Hua

Nanocomposites from ordered mesoporous materials

The size distribution and dispersion of nanomaterials, in addition to their dimensions, are crucial for their performance. Ordered mesoporous materials (OMMs), due to their periodic and size-controllable pore channels (2–10 nm) and high surface areas, have been regarded as “a natural micro-reactor” to construct novel ordered and well dispersed nanocomposites with controlled size and size distribution. In this review, we overview the recent developments in nanomaterials preparation and properties from ordered mesoporous materials over the last five years, focusing on materials preparation methodology and special properties. Finally, the present and future research interests of nanocomposites from OMMs will also be discussed.

Colloidal HPMO Nanoparticles: Silica‐Etching Chemistry Tailoring, Topological Transformation, and Nano‐Biomedical Applications

Hybridization produces the better: Colloidal hollow periodic mesoporous organosilica nanoparticles (HPMO NPs) with tunable compositions and highly hybridized nanostructures are successfully synthesized by a simple, easily scale-up but versatile silica-etching chemistry (alkaline or HF etching) for their applications in nano-fabrication and nano-medicine.

Hierarchical Mesoporous Zeolites: Direct Self‐Assembly Synthesis in a Conventional Surfactant Solution by Kinetic Control over the Zeolite Seed Formation

By kinetic control over the zeolite seed formation, we report the direct fabrication of hierarchical mesoporous zeolites using hexadecyl trimethyl ammonium bromide (CTAB) as the soft template in a conventional solution route. Nanometer-sized, subnanocrystal-type zeolite seeds with a high degree of polymerization are essential to prevent the formation of a separate amorphous mesoporous phase and the phase separation between the mesophase and zeolite crystals in the presence of CTAB and a certain amount of ethanol. The mechanisms for the formation of hierarchically porous zeolites in the solution process, including the effect of mother liquid aging, formation of subnanocrystal zeolite seeds and their self-assembly effect with CTAB, and the role of ethanol are proposed and discussed in detail. The prepared mesoporous ZSM-5 zeolite showed much higher catalytic activity than conventional counterparts for aldol condensations involving large molecules, especially in the synthesis of vesidryl.

Direct fabrication of mesoporous zeolite with a hollow capsular structure

We report the direct fabrication of mesoporous zeolite with a hollow spherical/ellipsoidal capsule structure by using conventional TPAOH and CTAB as soft micro- and mesopore generating templates; the mesoporous zeolite shows a high surface area of 717 m(2) g(-1) and small mesopore size of around 3 nm.

Templated synthesis of hierarchically porous manganese oxide with a crystalline nanorod framework and its high electrochemical performance

A simple approach has been developed to synthesize hierarchically porous MnO2 with a crystalline nanorod framework using mesoporous silica SBA-15 as a template, combined with in situ ion-exchange and surfactant-extraction processes without calcination. XRD, nitrogen adsorption analysis, FE-SEM, TEM, XPS and FT-IR techniques are used for the structural characterization. Such MnO2 materials show a macro–mesoporous hierarchical nanostructure containing large pores of several hundreds of nanometres and mesopores of 3.76 nm with a high surface area of 142 m2 g−1. The mesoporous framework of this material is composed of aligned single crystalline MnO2 nanorods of ca. 5–6 nm in diameter and ca. 20–25 nm in length. The electrochemical properties of the prepared MnO2 material were studied using cyclic voltammetry in a mild aqueous electrolyte, which shows that such a MnO2 nanostructure has a very high specific capacitance of 258 F g−1 and a good reversibility due to its favorable phase and hierarchically porous structure as well as high surface area.

The preparation and photoluminescence properties of ZnO-MCM-41

Abstract ZnO crystallites have been anchored within the pore channels of silica MCM-41 (named ZnO-MCM-41) through a chelation method of Zn2+ by ethyldiamino group (EN) on the inner surface. The structural and elemental composition analyses of the material were characterized by the SAXRD, XRD, BET, XPS and EDS under HRTEM techniques. The ZnO crystallites were about 1.7 nm estimated from the UV–Vis spectra. The bright UV (377 nm), violet (420 nm) and blue–green (480 nm) photoluminescence (PL) bands have been detected. The unfamiliar violet PL band is related to the oxygen vacancies on the ZnO–SiO2 interface traps.

One-step synthesis of sulfur doped graphene foam for oxygen reduction reactions

Sulfur doped graphene foam has been successfully synthesized by a simple solve-thermal method, which exhibited a much enhanced oxygen reduction reaction (ORR) catalytic activity as well as an especially high electrochemical stability, and would be a promising non-metal cathode catalyst for the ORR.

CTAB-templated mesoporous TS-1 zeolites as active catalysts in a desulfurization process: the decreased hydrophobicity is more favourable in thiophene oxidation

Mesoporous TS-1 zeolites (MTS-1) were prepared through direct hydrothermal treatment by using CTAB as the mesoporogen under the assistance of ethanol, and they demonstrated much higher catalytic activity and better recyclability in thiophene oxidation, due to the decreased hydrophobicity and mesoporous structure.

Highly dispersed Au nanoparticles incorporated mesoporous TiO2 thin films with ultrahigh Au content

Highly dispersed gold nanoparticles (NPs) incorporated mesoporous titania thin films with ultrahigh Au content (53.3 wt%) were synthesized by a deposition-precipitation method using urea as precipitator, which showed high off-resonant third-order optical nonlinear susceptibility (χ(3) = 2.69 × 10−8 esu) measured by the Z-scan technique at 1064 nm. The enhanced χ(3) value of the materials was attributed to the homogeneous dispersion and the ultrahigh concentration of the gold NPs, and the high linear refractive index of the titania matrix.

A micro/mesoporous aluminosilicate: key factors affecting framework crystallization during steam-assisted synthesis and its catalytic property

A hierarchical micro/mesoporous aluminosilicate has been synthesized using an optimized steam-assisted crystallization method, by which the material shows perfect crystallization of zeolite frameworks and relatively high surface area and meso/micropore volumes. Key factors for the crystallization of mesoporous frameworks in the process, especially the gel drying temperature, and role of triethanolamine as mesopore template, which have not been addressed before, were identified for the successful synthesis of the hierarchical structure in detail. An energy level schematic was proposed to illustrate the role of the gel drying temperature by affecting the condensation level of the -Si–O- network in the mesoporous framework. Alteration of the experimental conditions within a certain range can yield mesoporous zeolites with varied structure properties, such as surface area, pore volume and pore size. Such hierarchical structures possess remarkably higher catalytic activity in aldol condensation reaction than both amorphous mesoporous materials and conventional ZSM-5 zeolite.