Uniform hierarchical silica film with perpendicular macroporous channels and accessible ordered mesopores for biomolecule separation

Herein, we demonstrate that silica films with perpendicular macroporous channels and accessible ordered mesopores can be conveniently prepared. The hierarchical macroporous–mesoporous silica films are synthesized by using zinc oxide nanorod array as macroporous template and CTAB surfactant as mesoporous template. In basic surfactant-containing solution, ordered mesoporous silica shells homogeneously grow on the zinc oxide nanorod array. The growth of the mesostructures do not require any chemical modification for the zinc oxide nanorod, which opens a new way for preparing hierarchical silica films with perpendicular mesochannels. The prepared hierarchical macroporous–mesoporous silica films possess a uniform thickness of 2 mm, large perpendicular macropores with a length of 1.8 mm and a width of 80 nm, and accessible ordered mesopores. Separation experiment demonstrates that this macroporous–mesoporous film can effectively separate biomolecules with different sizes.     

Fabrication and characterization of hexagonal mesoporous silica monolith via post-synthesized hydrothermal process

Large-sized, optical transparent mesostructured Brij 56/silica monolith has been fabricated using a lyotropic liquid crystal of Brij 56 (C₁₆EO₁₀) as a template and TMOS as a silica source, combined with a optimizing sol-gel process and a hydrothermal aging process. By programmed temperature drying and calcinations, translucent mesoporous silica monolith with two-dimensional hexagonal structure (P6mm) has bee obtained. The ordered mesoporous silica monoliths have been characterized by small-angle X-ray diffraction, transmission electron microscopy (TEM), and nitrogen adsorption, which shows that the materials have a highly ordered two-dimensional hexagonal mesostructure with the high specific surface area of 837 m² · g⁻¹ and narrow pore distribution with a mean BJH pore diameter of 2.73 nm. Based on calculations and differential scanning calorimetry and thermogravimetric analyses, the action mechanism of the hydrothermal aging process has been proposed: the 100°C hydrothermal conditions and autogenous 2.3 atm pressure promote the condensation and dehydration of silanol groups, with the result that cross-linking degree, the flaws and moisture content in gels are reduced notably. Those processes guarantee the integrity of gels in the following drying process.     

Fabrication of MCM-41 mesoporous silica through the self-assembly supermolecule of β-CD and CTAB

Using the self-assembly β-cyclodextrin (β-CD) and cetyltrimethylammonium bromide (CTAB) as structure-directing agents, high-quality ordered MCM-41 silicas have been prepared. Small-angle X-ray diffraction (SXRD), N₂ adsorption-desorption and scanning electron microscope (SEM) techniques were used to characterize the calcined samples. Results showed that the pore structure of the resulting mesoporous silica belonged to the two-dimensional hexagonal structure (space group p6mm). The high-quality hexagonal structure was formed as n?1 (n denotes molar ratio of β-CD to CTAB). N₂ adsorption-desorption curves revealed type IV isotherms, H4 hysteresis loops, for all samples, and H1 hysteresis loops for samples at n=0, 0.1, 1 and 2, respectively. The pore size and the pore wall thickness of the samples increased with the increase in n values, respectively.     

Functional ligands and complexes for new structures, homogeneous catalysts and nanomaterials

In this account, we focus on results from our laboratory to illustrate recent developments in various fields of organometallic chemistry. Studies on hemilabile P,N donor ligands and on the ion-pair behaviour of cationic Pd(II) complexes have led to the full characterization of complexes with η¹-allyl ligands. This still rare bonding mode for the allyl ligand in palladium chemistry allows facile insertion of CO into the Pd-C σ-bond, in contrast to the situation in related η³-allyl Pd(II) complexes. In order to develop new homogeneous catalysts for the selective dimerization and oligomerization of ethylene, a range of Ni(II) complexes have been prepared with new chelating P,N ligands where P represents a phosphine, phosphinite or phosphonite donor group and N a pyridine or oxazoline moiety. Finally, we shall examine bottom-up approaches to the formation of new nanomaterials of magnetic or catalytic interest by covalent anchoring of metal complexes and clusters into mesoporous materials using functional phosphine or alkyne ligands containing an alkoxysilyl group.     

Fabrication of sulfonated mesoporous carbon by evaporation induced self-assembly/carbonization approach and its supercapacitive properties

Synthesis of functionalized mesoporous carbon by an easy-accessed method is of great importance towards its practical applications.Herein,an evaporation induced self-assembly/carbonization(EISAC) method was developed and applied to the synthesis of sulfonic acid group functionalized mesoporous carbon(SMC).The final mesoporous carbon obtained by EISAC method possesses wormlike mesoporous structure,uniform pore size(3.6 nm),large surface area of 735 m²/g,graphitic pore walls and rich sulfonic acid group.Moreover,the resultant mesoporous carbon achieves a superior electrochemical capacitive performances(216 F/g)to phenolic resin derived mesoporous carbon(OMC,152 F/g)and commercial activated carbon(AC,119 F/g).     

Electrodeposition of nanostructured catalysts for electrochemical energy conversion: Current trends and innovative strategies

This review discusses the latest advances in electrodeposition of nanostructured catalysts for electrochemical energy conversion: fuel cells, water splitting, and carbon dioxide electroreduction. The method excels at preparing efficient and durable nanostructured materials, such as nanoparticles, single atom clusters, hierarchical bifunctional combinations of hydroxides, selenides, phosphides, and so on. Yet, in most cases, chemical composition cannot be decoupled from catalyst morphology. This compromises the rational design of electrodeposition procedures because performance indicators depend on both morphology and surface chemistry. We expect electrodeposition will keep unraveling its potential as the preferred method for electrocatalyst synthesis once a deeper understanding of the electrochemical growth process is combined with complex chemistries to have control of the morphology and the surface composition of complex (bifunctional) electrocatalysts.     

Preparation of mesoporous TiO2/CNT nanocomposites by synthesis of mesoporous titania via EISA and their photocatalytic degradation under visible light irradiation

Stabilized mesoporous TiO₂ was synthesized by evaporation induced self assembly (EISA) method and mechanically incorporated into single-walled carbon nanotubes (SWCNT) with different ratios. The physicochemical properties of the nanocomposites (mesoporous TiO₂/SWCNT) materials were investigated by Brunauer–Emmett–Teller (BET) measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), photoluminescence (PL) and ultraviolet–visible (UV–Vis) spectroscopy measurements. The catalytic activity of mesoporous TiO₂ and nanocomposites were assessed by examining the degradation of rhodamine B as model aqueous solution under visible light. CNTs are facilitating the photocatalytic activity of mesoporous TiO₂ in the degradation of rhodamine B efficiently.     

Room temperature solution-phase synthesis of flower-like nanostructures of [Ni3(BTC)2·12H2O] and their conversion to porous NiO

Hierarchical flower-like architectures of[Ni₃（BTC）₂·12H₂O]（BTC³=benzene-1,3,5-tricarboxylate） were successfully prepared by a simple solution-phase method under mild conditions without any template or surfactant.Phase-pure porous NiO nanocrystals were obtained by annealing the Ni-BTC complex without significant alteration in morphology.The product was characterized by X-ray diffraction techniques,field-emission scanning electron microscopy（FESEM）.transmission electron microscopy（TEM） and high-resolution TEM（HRTEM）.The catalytic effect of the NiO product was investigated on the thermal decomposition of ammonium perchlorate（AP） and it was found that the annealed NiO product has higher catalytic activity than the commercial NiO.     

Design of Sensitive Biocompatible Quantum‐Dots Embedded in Mesoporous Silica Microspheres for the Quantitative Immunoassay of Human Immunodeficiency Virus‐1 Antibodies

A novel sandwich‐type electrochemiluminescence (ECL) immunosensor was developed to enable the sensitive detection of HIV‐1 antibodies. This system incorporated mesoporous silica (mSiO₂) complexed with quantum dots (QDs) and nano‐gold particles, which were assembled to enhance signal detection. Magnetic beads were used by immobilizing the secondary anti‐IgG antibody. This was first employed to capture HIV‐1 antibody (Ab) to form a Fe₃O₄/anti‐IgG/Ab complex. A high loading and signal‐enhanced nanocomposite (hereafter referred to as Au‐mSiO₂‐CdTe) was used as a HIV‐1 antigen label. The Au‐mSiO₂‐CdTe nanocomposite was conjugated with the Fe₃O₄/anti‐IgG/Ab complex to form an immunocomplex (hereafter referred to as Fe₃O₄/anti‐IgG/Ab/HIV‐1/CdTe‐mSiO₂‐Au). This complex could be further separated by an external magnetic field to produce ECL signals. Due to the large specific surface area and pore volume of mSiO₂, the loading of the CdTe QDs was markedly increased. Thus, the loaded QDs released a powerful chemiluminescent signal with a concordantly increased sensitivity of the immunosensor. The immunosensor was highly sensitive, and displayed a linear range of responses for HIV‐1 antibody across a dilution range of 1 : 1500 through 1 : 50 with the detection limit of 1 : 4500. The immunoassay can be a promising candidate in early diagnosis of HIV infection.     

Immobilization of Pd Catalysts on Mesoporous Silica for Amine- and Copper-Free Sonogashira Coupling Reactions

Immobilization of catalysts on solid supports is a promising approach to combine the advantages of heterogeneous and homogeneous catalysts. Pd(PPh₃)₂Cl₂, known as an extremely active homogeneous catalyst for the Sonogashira coupling reaction, has been immobilized on high-surface-area MCF (mesocellular foams)–type mesoporous silica powder modified with 3-aminopropyltriethoxysilane and subsequently with diphenylphosphine. The functionalized MCF-type silica and supported catalysts have been characterized by x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), elemental analysis, nitrogen sorption porosimetry, and scanning electron microscopy (SEM). Such supported Pd catalysts have proven to be useful recyclable reagents for copper- and amine-free Sonogashira coupling reactions of haloaromatic compounds with terminal alkynes.