Performance characteristics of organic–inorganic composite electrodes in magnesium reserve batteries

Electrochemical characteristics of m-dinitrobenzene (m-DNB) based composite cathode materials involving compounds such as AgCl, TiO₂, HgO and CuCl have been investigated and (Mg AZ31 alloy anode) as an activated battery system using 2 M magnesium perchlorate aqueous electrolyte. The concentration of the composites has been optimized so as to obtain high electrochemical performance of Mg/m-DNB reserve batteries through constant current discharge studies. Mg/m-DNB cells containing 5-wt % of HgO when discharged at current density of 2.1 mA cm⁻² delivered 5.3 Ah capacity corresponds to a columbic efficiency of 97% as compared to the cells without composite.     

Preparation and characterization of photopolymerizable organic–inorganic hybrid materials by the sol-gel method

A series of UV-curable organic–inorganic hybrid materials were prepared by the sol-gel technique and coated onto Plexiglass^® substrate. The effects of the content of EGDMA and the content of the inorganic part on various properties of the coatings, such as tensile strength, hardness, gloss, and cross-cut adhesion, were investigated. It was found that the properties of the coating were improved by the addition of an inorganic part. The thermal properties of the hybrids were enhanced by incorporating silane sol into the organic part. Furthermore, it was found that the coating containing silica had a higher char content at 800 °C than the coating without silica. SEM studies indicated that nanosized (about 50 nm) silica particles were evenly dispersed throughout the organic matrix. A photo-DSC investigation showed that the organic coating polymerized more quickly than the hybrid coating.     

UV-induced grafting of organic–inorganic antibacterial membrane on wool fiber

Wool fiber was modified by UV irradiation and then reacted with cross-linked chitosan-coated Ag-loading nano-SiO₂ (CCTS-SLS) composites to prepare antibacterial wool fiber. The results show the topography of wool surface was also modified along with the formation of active radicals during UV irradiation. These active groups were used to graft antibacterial materials CCTS-SLS. Compared with parent wool fiber, the antibacterial wool fiber was improved in dyeing property. The dyeing uptake increased by 98% in a dyeing time of 50 min. Also, the antifelting performance increased as a result of the decrease in directional frictional effect after UV irradiation modification.     

Synthesis of ZrB2/SiC composite powders by single-step solution process from organic–inorganic hybrid precursor

A precursor of a zirconium diboride/silicon carbide (ZrB₂/SiC) composite was synthesised via an organic–inorganic hybrid derived from gum karaya, tetraethyl orthosilicate, boric acid and zirconyl chloride starting materials. Fourier transform infrared spectroscopy of the as-synthesised dried hybrid revealed the formation of Si–O, Zr–O–C and B–O–B. X-ray diffraction revealed that the powder consists of only ZrB₂ and β-SiC. Scanning electron microscopy and TEM of the composite powders showed that SiC and ZrB₂ occurred in intimately mixed aggregates of spheroidal submicron sized particles for low (3M) boric acid concentration, while at high (5M) boric acid concentration, the two phases are larger with the ZrB₂ adopting a blocky, angular morphology (～10–30?μm long by 5?μm wide and thick), while the SiC remains spheroidal with ～1?μm diameter particles in 10–20?μm diameter aggregates. Thermogravimetry–differential thermal analysis with the help of X-ray diffraction analysis revealed that the formation temperature was low at 1275°C for ZrB₂ and 1350°C for the SiC with 40?wt-% yield.     

WGS activity of a novel Cu–ZrO2 catalyst prepared by a reflux method. Comparison with a conventional impregnation method

The activity in the WGS reaction of Cu/ZrO₂ catalysts prepared by a method of refluxing in an aqueous NH₄OH solution is studied. It is shown that at 3% Cu load the methods of impregnation over monoclinic or tetragonal ZrO₂ do not produce active catalysts for the WGS reaction. However, the method of refluxing generates highly active catalysts with Cu loads of 3% (w/w) or higher. The activity of the catalysts prepared by refluxing is associated with the formation of small Cu clusters, which would allow the regrouping of the H atoms to generate molecular H₂ in the presence of the crystalline tetragonal ZrO₂.     

Microstructure and mechanical properties of quasi-isotropic chopped fiber-reinforced PyC–SiC matrix composite prepared by novel nondamaging method

In this work, quasi-isotropic chopped carbon fiber-reinforced pyrolytic carbon and silicon carbide matrix (C_f/C–SiC) composites and chopped silicon carbide fiber-reinforced silicon carbide matrix (SiC_f/SiC) composites were prepared via novel nondamaging method, namely airlaid process combined with chemical vapor infiltration. Both composites exhibit random fiber distribution and homogeneous pore size. Young's modulus of highly textured pyrolytic carbon (PyC) matrix is 23.01 ± 1.43 GPa, and that of SiC matrix composed of columnar crystals is 305.8 ± 9.49 GPa in C_f/C–SiC composites. Tensile strength and interlaminar shear strength of C_f/C–SiC composites are 52.56 ± 4.81 and 98.16 ± 24.62 MPa, respectively, which are both higher than those of SiC_f/SiC composites because of appropriate interfacial shear strength and introduction of low-modulus and highly textured PyC matrix. Excellent mechanical properties of C_f/C–SiC composites, particularly regarding interlaminar shear strength, are due to their quasi-isotropic structure, interfacial debonding, interfacial sliding, and crack deflection. In addition to the occurrence of crack deflection at the fiber/matrix interface, crack deflection in C_f/C–SiC composites takes also place at the interface between PyC–SiC composite matrix and the interlamination of multilayered PyC matrix. Outstanding mechanical properties of as-prepared C_f/C–SiC composites render them potential candidates for application as thermal structure materials under complex stress conditions.     

Performance of Pd–Ag/Al2O3 catalysts prepared by the selective deposition of Ag onto Pd in acetylene hydrogenation

The performance of Ag-promoted Pd/Al₂O₃ catalysts, which were prepared by the selective deposition of Ag onto Pd using a surface redox (SR) method, during acetylene hydrogenation was compared with that of catalysts prepared by impregnation. The Pd surface was more effectively modified with Ag added by SR, even when small amounts of Ag were added. The catalyst prepared by SR showed a higher ethylene selectivity than the one prepared by impregnation, because SR allowed both the preferential deposition of Ag on the low-coordination sites of Pd and a greater electronic modification of Pd by Ag.     

Preparation and use of hybrid organic–inorganic catalysts

Various approaches towards the immobilization of molecular homogeneous catalysts are introduced, focusing on catalysts where an organic molecule is attached to the surface of an inorganic support material via a covalent bond forming the so-called hybrid organic–inorganic catalysts. The application of this new class of catalysts in a wide variety of organic reactions is reviewed.     

Preparation of polyaniline–palladium composite microflakes by one-step interface polymerization method

Polyaniline–palladium (PANi-Pd) composite microflakes were synthesized through an immiscible organic/inorganic biphasic system in the presence of poly(ethylene glycol) with molecular weight 4,000 (PEG4000). Aniline was oxidized by PdCl₂ in the interface polymerization system, yielding PANi microflakes and elemental Pd nanoparticles simultaneously. Palladium nanoparticles were uniformly dispersed in the microflakes of PANi. The results of FTIR spectra suggested that the oxidation degree of PANi was affected by the initial ratio of metal ions to monomer. The PANi-Pd composites were characterized using X-ray photoelectron spectroscopy and the conductivity of the composite was measured by conventional four-probe method. Scanning and transmission electron microscopy were used to show the morphology of the composites.     

Synthesis of high performance organic–inorganic composite via click coupling of block polymer and polyhedral oligomeric silsesquioxane

Novel hybrid systems based on poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) and a polyhedral oligomeric silsesquioxane (POSS) have been synthesized via click chemistry. Different compositions of SEBS-functionalized POSS were obtained from the reaction of azide-functionalized styrene units of SEBS with alkyne-functionalized POSS molecules. Characterization of SEBS-functionalized POSS by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance spectroscopy revealed that the POSS molecules were successfully attached to the phenyl group of the SEBS polymer chain following the click reaction. Homogeneous dispersion of POSS molecules in the polymer matrix was demonstrated by scanning electron microscopy. The POSS molecule showed excellent compatibility with polymer matrix, and as a consequence the remarkable enhancement of mechanical properties (breaking stress = 44%, modulus = 285%) and thermal stability for the resulting composite films was achieved. The reinforcing effect is ascribed to both the compatible homogeneous dispersion of POSS in the matrix and the covalent bond between SEBS and POSS molecules arising from the click coupling.     

Dielectric properties of SrTiO3/LaNiO3 composite structure prepared by “sol-gel” method

In this work, Pt/SrTiO₃(STO)/LaNiO₃(LNO) and Pt/STO/Pt structures were fabricated on Si substrates using sol–gel method. Dielectric tunability characteristics of these two structures are investigated over temperature range of 300–80 K. As temperature decreases, relative dielectric constant and tunability of STO films in both structures increase linearly, while loss tangent (tan?) decreases. STO prepared on LNO exhibits better crystallinity and dielectric tunability than that prepared on Pt. Furthermore, LNO top pole array with 0.2 mm diameter was prepared on STO/LNO using photosensitive sol–gel method, resulting in LNO/STO/LNO structure with symmetric electrode. Dielectric tunability tests reveal that, compared with Pt/STO/LNO structure, LNO/STO/LNO structure exhibits similar tunability, lower tan?, higher figure-of-merit (FOM) values, and better tunability symmetry. Relative dielectric constant, tunability (350 kV/cm), and FOM are approximately 391, 60%, and 142.6 at 80 K, respectively. Further analysis shows that because of Schottky barrier at Pt/STO interface, the FOM and tunability symmetry of Pt/STO/LNO structure are worse than those of LNO/STO/LNO structure. These results demonstrate that LNO electrode performs better than conventional inert metal electrodes.     

Scaling salts removal in RO concentrates by inorganic induced method

Introduction Scaling on heat transfer surface[1 ,2]andreverse osmosis ( RO) membrane surface[3]is one of the main problems in desalination processes· To mitigate scales , anti-scalants are often used·For RO system, membrane concentrates contain high amo…     

In situ growth of carbon nanotubes in alumina–zirconia nanocomposite matrix prepared by solution combustion method

In this work successful synthesis of multiwall carbon nanotube (CNT) using solution combustion and chemical vapor deposition (CVD) methods are reported. Ceramic nanocomposite samples of (Al_2?xFe_xO₃)–(y)ZrO₂ formula with x = 0.017, 0.034 and 0.17 and y = 0.15 were initially prepared. These were then subjected to CVD process during which the in situ reduction of iron oxide to metallic iron (Fe/Fe₃C) phase/s provided the necessary catalyst for the CNT formation. The formation of long flexible filaments with a smooth and regular surface bridging between alumina–zirconia (AZ) grains could be detected. The diameters of the formed filaments were in the range of ～70 to ～320 nm and length of the order of some tens of micrometers. However, transmission electron microscope (TEM) examinations also revealed the existence of small amounts of Bamboo-like carbon along with more or less straight CNTs. This could be related to the lack of strong interactions between the metallic iron phase/s and the nanocomposite support.     

Adsorption of chromate and para-nitrochlorobenzene on inorganic–organic montmorillonite

Batch studies of chromate and para-nitrochlorobenzene (p-NCB) on montmorillonite modified by poly(hydroxo aluminium) ions (Al) and cetyl trimethylammonium bromide (CTMAB) are reported. The amounts adsorbed decreased in the order Al-CTMA-mont > CTMA-mont > Al-mont > montmorillonite. Adsorption of chromate on Al-CTMA-mont reached a maximum at pH = 4 while p-NCB was pH independent. The adsorption kinetics could be described by the pseudo-second-order model. The adsorption rates for chromate and p-NCB were 9.73 and 5.78 mg g^? 1 min^? 1, respectively. The adsorption capacity of chromate and p-NCB on Al-CTMA-mont calculated by the Langmuir model was 2.3 × 10^? 4 and 2.2 × 10^? 4 mol/g, the values of the adsorption energy of the Dubinin-Radushkevitch (D-R) model were 13.9 and 7.8 kJ/mol. These results implied that the chromate adsorption proceeded as chemisorption, mainly by ion exchange whereas p-NCB was bound by van der Waals forces.     

Effect of carbon nanotubes on sintering behavior of alumina prepared by sol–gel method

Alumina (Al2O3)/carbon nanotube (CNT) (99/1 by weight) composite was prepared by mixing CNT dispersion with AlCl₃-based gel, followed by high temperature sintering at a temperature up to 1150 °C in argon. Composite alumina precursor showed phase transition order from amorphous to γ-Al₂O₃ after sintered at 900 °C for 2 h, partially to θ-Al₂O₃ after sintered at 1000 °C for 2 h, and then partially to α-Al₂O₃ after sintered at 1150 °C for 2 h. By comparison, control alumina precursor directly transformed from amorphous to α-Al₂O₃ after sintered at a relatively low temperature of 600 °C for 2 h. Composite alumina showed porous structure with pore diameter ranging from 100 nm to 2 µm, whereas control alumina was relatively pore-free. The elevated alumina-crystal phase transition temperatures and the formation of porous structure were ascribed to the presence of CNTs in alumina precursor. The composite alumina sintered at 900 °C for 2 h containing only γ-Al₂O₃ had a BET surface area of 138 m²/g, which was significantly higher than that of control alumina sintered at 1150 °C for 2 h containing only α-Al₂O₃, ~15 m²/g.     

Application of Psf–PPSS–TPA composite membrane in the all-vanadium redox flow battery

The Psf–PPSS–TPA composite cation exchange membrane consist of Psf(polysulfone)–PPSS (polyphenylenesulfidesulfone) block copolymer with TPA (tungstophosphoric acid) is prepared to apply for a separator in the all-vanadium redox flow battery. The membrane properties such as membrane resistance and ion exchange capacity, and thermal stability are investigated. The prepared Psf–PPSS–TPA composite cation exchange membrane showed higher thermal stability than Nafion117. The lowest membrane resistance of the prepared Psf–PPSS–TPA composite cation exchange membrane measured in 1 M (mol/dm³) H₂SO₄ aqueous solution was 0.94 Ω cm² at 0.5 g of TPA solution. The performance properties of the all-vanadium redox flow battery (V-RFB) using the prepared cation exchange membrane are measured. The electromotive force, open circuit voltage at state of charge (SOC) of 100%, was 1.4 V. This value meets a theoretical electromotive force value of the V-RFB. The measuring cell resistance in charge and discharge at SOC 100% were 0.26 Ω and 0.31 Ω, respectively. The results of the present study suggest that the prepared Psf–PPSS–TPA composite cation exchange membrane is well suited for use in V-RFB as a separator.     

Physical modification of polymeric support layer for thin film composite forward osmosis membranes by metal–organic framework-based porous matrix membrane strategy

Physical modification of support layers (SLs) for thin-film composite (TFC) forward osmosis (FO) membranes is the main goal of this study. Accordingly, the strategy of metal–organic framework (MOF)-based porous matrix membrane (PMM) was used for the fabrication of controllable SLs. Fourteen different TFC FO membranes were successfully fabricated by interfacial polymerization (IP) technique over the fourteen different SLs made of polyetherimide (PEI), polyethersulfone (PES), and twelve MOF-based PMM. The controllable MOF particles, fabricated SLs, and TFC membranes were characterized by Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle (CA), inductively coupled plasma (ICP), and developed SHN1 method. The results showed that the PMM strategy can lead to an increase in the degree of crosslinking of polyamide (PA) as a result of physical modification of the original SLs. Also, the PMM strategy reduced the structural parameters and hence the internal concentration polarization (ICP) was controlled. However, according to the characteristic curve, physical modification of the structure of PES and PEI by MOF-based PMM strategy caused a small and dramatic effect (respectively) on the performance of the TFC FO membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48672.     

Hydrodeoxygenation of p-cresol on unsupported Ni–P catalysts prepared by thermal decomposition method

Unsupported Ni–P catalysts were prepared from the mixed precursor of NiCl₂ and NaH₂PO₂ by thermal decomposition method, and their catalytic activities were measured using the hydrodeoxygenation (HDO) of p-cresol as probe. The effects of the H₂PO₂⁻/Ni^2 + molar ratio in the precursor and the thermal decomposition temperature on the catalyst purity, crystallite size and HDO activity were studied. The HDO of p-cresol on these Ni–P catalysts proceeded with two parallel pathways yielding methylbenzene and methylcyclohexane as final products. The higher HDO catalytic activity of the catalyst was attributed to its bigger crystallite size and purer phase of Ni₂P.