Mohammad A. Wahab

Highly ordered macro-mesoporous carbon nitride film for selective detection of acidic/basic molecules

Well-ordered meso-macroporous carbon nitride film fabricated via a simple and flexible template replication method by using the P123 block copolymer and polystyrene spheres as dual templates shows selective sensing performance for acetic acid but after treating the surface of the film with UV light and oxygen, the selectivity of sensing can be tuned for basic molecules.

Ruthenium-functionalised hybrid periodic mesoporous organosilicas: synthesis and structural characterization

This paper describes a new method for incorporating various amounts of ruthenium species (Ru) into hybrid periodic mesoporous organosilicas (HPMO). The effects that the Si : Ru ratio has on the Ru-containing HPMO materials (Ru-HPMO) were determined by powder X-ray diffraction (XRD), N2 sorption, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), solid state 29Si and 13C nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The Ru-HPMO materials exhibited type-H4 hysteresis loops at p/po ratios between 0.45 and 1 and contained some structural defects amid their nanochannels. The hysteresis loop is associated with pore blocking in the mesostructures, which we correlated with the Ru content. The presence of Ru and Si–C bonds in the Ru-HPMOs was confirmed by XPS and NMR spectroscopy, respectively. The analyses also indicated the presence of Ru species within the pores of the host material. Controlled loading of Ru was possible up to a maximum of 25 wt.%. The well-defined morphologies were produced as a result of a combination of disclination and dislocation defects toward the growth of liquid crystals. Moreover, TEM images suggest that the resulting uniform mesoporous structure of Ru-HPMO was maintained even at high Ru loadings.

Nano-confined ammonia borane for chemical hydrogen storage

There is a great demand for a sufficient and sustainable energy supply. Hence, the search for applicable hydrogen storage materials is extremely important owing to the diversified merits of hydrogen energy. In this regard, ammonia borane (NH3BH3, AB) containing 19.6 wt-% hydrogen has been considered as a promising material for hydrogen storage applications to realize the “hydrogen economy”, but with limits from slow kinetics of hydrogen release and by-product of trace gases such as ammonia and borazine. In this review, we introduce the recent research on AB, regarding to the nanoconfinement effect on improving the kinetics at a relatively low temperature and the prevention/reduction of undesirable gas formation.

Synthesis and Characterization of Novel Amorphous Hybrid Silica Materials

Novel amorphous organic-inorganic hybrid silica materials have been prepared by the conventional sol-gel reaction of bis(gamma-trimethoxysilyl)propylamine (TMSPA) and tetraethyl orthosilicate (TEOS) in the presence of cetyltrimethylammonium bromide (CTABr) as a structure directing agent. The gelation of the hybrid silica gels took place faster as the TMSPA composition was higher. Infrared Spectroscopy (IR), Thermogravimetric Analysis (TGA), X-Ray Diffraction (XRD), and Scanning electron microscope (SEM) were used to characterize various hybrid materials. Nitrogen adsorption desorption isotherms at 77 K were used to determine the surface area, and average pore size. The hybrids were composed of macropores and a small amount of micropores. According to SEM photographs, the hybrids were composed of quite uniform aggregate of spherical particles with ca. 60 nm in diameter.

Recent advances in hybrid periodic mesostructured organosilica materials: opportunities from fundamental to biomedical applications

Surfactant-mediated periodic mesoporous organosilicas (PMOs) with different organic and inorganic functions in the framework structure were discovered in 1999. The silica inorganic function gives a strong mechanical stability to the framework structure and the organic functionality creates more structural flexibility. As a result, their use is optimal for a large number of applications including catalysis, microelectronics, chromatographic supports, selective adsorbents, sensors, protein folding, biomedical devices and light-harvesting devices. These new materials showed also superior stability when compared to pure mesoporous silica (PMS) framework structures. Based on the recent discoveries, since 2012, this review mostly provides a comprehensive overview of their multidisciplinary options for various applications.

Nano-hard template synthesis of pure mesoporous NiO and its application for streptavidin protein immobilization

A simple and efficient immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO is described. Before immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO, we first synthesized well-organized mesoporous NiO by a nanocasting method using mesoporous silica SBA-15 as the hard template. Then, the well-organized mesoporous NiO particles were characterized by small angle x-ray diffraction (XRD), wide angle XRD, nitrogen adsorption/desorption, and transmission electron microscopy (TEM). TEM and small angle XRD suggested the formation of mesoporous NiO materials, whereas the wide angle XRD pattern of mesoporous NiO indicated that the nickel precursor had been transformed into crystalline NiO. The N2 sorption experiments demonstrated that the mesoporous NiO particles had a high surface area of 281 m2 g(-1), a pore volume of 0.51 cm3 g(-1) and a pore size of 4.8 nm. Next, the immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO was studied. Detailed analysis using gel electrophoresis confirmed that this approach can efficiently bind his-tagged streptavidin onto the surface of mesoporous NiO material since the mesoporous NiO provides sufficient surface sites for the binding of streptavidin via non-covalent ligand binding with the histidine tag.

Polyimide Based Hybrid Nanocomposites

Polyimides(PIs)have been used as attractive matrix polymers for hybrid composites due to their good thermo-mechanical properties. Properties of the polyimide based hybrid nanocomposites can be obtained in a wide range by dispersing inorganic nanoparticles via sol-gel process during thermal imidization. This review concerns a brief summary of microstructure, interfacial interaction, and properties of the polyimide based hybrid nanocomposites.

Fluorescence Spectroscopic and Atomic Force Microscopic Studies on the Microstructure of Polyimide/Silica-Titania Ternary Hybrid Composites

Biphenyltetracarboximide-phenylene diamine polyimide/silica-titania ternary hybrid composites were prepared by thermal imidization and sol-gel reaction. Fluorescence spectroscopic, scanning electron microscopy, and atomic force microscopy studies revealed that the addition of small amount of titania showed profound effects on the microstructure and photophysical behaviors of polyimide/silica hybrid composites, when the content of silicatitania mixture was small or when the ratio of silica to titania in the mixture was high.

Microstructure and interfacial interaction of polyimide/silica hybrid nanocomposites prepared with 3-aminopropyltriethoxysilane

A series of polyimide (PI)-silica hybrid nanocomposites are prepared from 3,3′,4,4′biphenyltetracarboxylic dianhydride (BPDA)-4,4′-oxydianiline (ODA) polyamic acid (PAA) and tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS) by the sol-gel process. 3-Aminopropyltriethoxysilane (3-APS) is used to enhance the interfacial interaction between polyimide and silica. The morphology, interfacial interaction, and properties of the hybrids are investigated using scanning electron microscope (SEM), UV-vis spectroscopy, atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). SEM and AFM images indicate that silica particles of ca. 45-55 nm size are uniformly distributed in polyimide matrices and that the interfacial interaction between PI and TEOS is better than that between PI and TMOS. The optical transparencies of the PI/TEOS hybrids are better than that of the PI/TMOS hybrids. FTIR spectra confirm the Si O Si bond as well as the conversion of PAA to polyimide and PI/silica hybrid films. The thermal stability is increased after incorporation of the silicas in the polyimide matrix.

Highly Selective Synthesis of Ortho‐Prenylated Phenols and Chromans by using a New Bimetallic CuAl‐KIT‐5 with a 3D‐Cage‐type Mesoporous Structure

A nice piece of KIT: The first synthesis of a new bimetallic 3D-cage-type mesoporous catalyst CuAl-KIT-5 and its remarkable performance for the highly selective synthesis of ortho-prenylated phenols and chromans is reported.