The dispersion and coordination of aluminium species on the surface of silica-alumina based materials are essential for controlling their catalytic activity and selectivity. Al and Al are two common coordinations of Al species in the silica network and alumina phase, respectively. Al is rare in nature and was found hitherto only in the alumina phase or interfaces containing alumina, a behavior ...

To discuss the potential role of the support for iridium catalyst, we have proceeded to prepare a series of supported catalysts with the same active phase content, but different silica content, to elucidate the changes in surface structure and the reaction process of hydrous hydrazine decomposition on catalyst. The obtained iridium catalysts contained 20 wt% of nanoparticles dispersed on spheri...

The negative and positive effects of alumina nanoparticles have been reported for various plant species, while the mechanism that brings about these effects has not yet been clearly understood. Here, the effects of different concentrations of nano-scale alumina on growth and enzymatic antioxidant system of wheat seedlings are investigated. The results show while root growth is affected by the n...

Nanoscale, zero-valent iron is a promising reagent for in situ reduction of a variety of subsurface contaminants, but its utility in full-scale remediation projects is limited by material costs. Iron nanoparticles (20-100 nm diameter) supported on carbon (C-Fe0) were synthesized by reacting iron salts, adsorbed or impregnated from aqueous solutions onto 80 m2/g carbon black, at 600-800 degrees ...

Abstract: Nano- size alumina particles have been synthesized by mechanical activation of a dry powder mixture of AlCl3 and CaO. Mechanical milling of the above raw materials with the conditions adopted in this study resulted in the formation of a mixture consisting of crystalline CaO and amorphous aluminum chlorides phases. There was no sign of chemical reaction occurring during milling stag...

A series of bulk oxides (Sb2O3, Sb2O4, VSbO4, and V2O5) and alumina-supported oxides (Sb-O, V-O, and Sb-V-O) were synthesized by conventional methods. The resulting catalysts were characterized with XRD, BET, Raman, and CH3OH-temperature programmed surface reaction (TPSR) spectroscopy. XRD and Raman spectroscopy confirmed that the bulk oxides are present as crystalline phases and the alumina-su...

Solid lubricants are commonly found in applications where more traditional lubrication techniques are undesirable or precluded. Polytetrafluoroethylene (PTFE) is an attractive solid lubricant, but high wear rates limit its use. While nanofillers have been found, in some cases, to provide wear resistance without introducing other detrimental effects, the mechanisms of wear resistance remain uncl...

adhesive bonding technology is being used in a variety of modern industries, including the automotive, aerospace, maritime, construction, defense and so on. on the other side, polymeric nano - composites attracted both academic and industrial interests in the past decades. the scope of this paper is experimental investigation on the effects of the addition of alpha-alumina nanoparticles to the ...

A mathematical model of micropolar squeezing flow nanofluids between parallel planes is taken into consideration under the influence effective Prandtl number using ethyl glycol (C2H6O2) and water (H2O) as base fluids along with nanoparticles gamma alumina (γAl2O3). The governing nonlinear PDEs are changed a system ODEs via suitable transformations. RKF (Range–Kutta–Fehlberg) technique used to s...

The effect of catalyst particle size on dehydration of methanol to dimethyl ether is investigated using fixed bed and micro-channel reactors at different temperatures and weight hourly space velocities. The experiments were carried out at 290 and 320oC. The space velocities were changed from 10 up to 90h-1 and from 1.22 to 3.65h-1 for fixed bed and micro-channel reactors, respectively. Consider...