In this study, B modified silicide coatings were prepared on Nb-Si based alloy with Al2O3 or SiO2 inert-filler by pack cementation technology. Both primarily consisted of a (Nb,X)Si2 (Nb,X)B2 + outer layer. After oxidation at 1250 °C for 100 h, the showed good resistance due to formation dense silica. The products coating SiO2, TiO2 and Cr2O3, while that TiO2, HfO2. different may be process the...

We use density functional theory to examine structure− activity relationships of small vanadia clusters supported on anatase TiO2(001) and rutile TiO2(110) surfaces. A thermodynamic analysis indicates that the vanadia monomer cluster can be stabilized on the anatase TiO2(001) surface in a catalytically relevant oxygen environment. On the other hand, vanadia clusters tend to aggregate into dimer...

The surface force apparatus (SFA) was utilized to obtain force-distance profiles between silica-supported membranes formed by Langmuir-Blodgett deposition of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). In the absence of a membrane, a long-range electrostatic repulsion and short-range steric repulsion are measured as a result of the deprotonation of silica in water and the roughness of t...

Mesoporous silica molecular sieves are a kind of unique catalyst support due to their large pore size and high surface area. Several methods have been developed to immobilize heteropolyacids (HPAs) inside the channels of these mesoporous silicas. The mesoporous silica-supported HPA materials have been widely used as recyclable catalysts in heterogeneous systems. They have shown high catalytic a...

The surface characteristics of hydrous silica-coated TiO particles are experimentally studied. Different analytical techniques were 2 Ž . used to characterize the Si oxide coatings on TiO particles. The high-resolution transmission electron microscope HRTEM , z-potential 2 Ž . analyzer and X-ray photoelectron spectroscope XPS analyses show that hydrous silica is continuously coated on the surfa...

The hydrogenation of crotonaldehyde in the presence of supported platinum nanoparticles was used to determine how the interaction between the metal particles and their support can control catalytic performance. Using gas-phase catalytic reaction studies and in situ sum-frequency generation vibrational spectroscopy (SFG) to study Pt/TiO2 and Pt/SiO2 catalysts, a unique reaction pathway was ident...

When used as additives, silicas strongly promoted the epoxidation of cyclooctene by (t)BuOOH in the presence of Ti-silsesquioxane (Ti-POSS), where Ti species were found to be bound to the silica surface. Based on this observation, highly-active silica-supported Ti catalysts were prepared by the thermal treatment of mixtures of Ti-POSS and silica.

Supported transition metal oxides and vanadium-containing multi-metallic oxides were investigated to develop new catalysts for the catalytic destruction of highly toxic polychlorinated aromatic pollutants such as polychlorinated benzenes, polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and/or biphenyls (PCBs) from waste gases. The decomposition of 1,2-dichlorobenzene (Cl2Bz) w...