In the present study, the gamma alumina (γ-Al2O3) nano powders have been prepared with addition of 1%mol Co using an aqueous sol-gel method at lower temperature than the pure gamma alumina. The synthesis process accomplished by partial hydrolysis of the aqueous solution of metallic ions Al3+ and Co2+, with ammonia. The Al(NO3)3.9H2O and Co(NO3)2.6H2O salts were used as cations sources. The obta...

Introduction: The effects of different solid substrates including: carbon nanofibers (CNFs), activated carbon, alumina, silica, and poly vinyl pyrolidone (PVP) were compared for high pressure synthesis of polytetrafluoroethylene (PTFE, (CF2)n) nanoparticles via the adsorption of thermally synthesized tetrafluoroethylene (TFE, C2F4) as monomer. Aim: Syntheses and characterization PTFE nanopartic...

Pulsed Laser Ablation in Liquid (PLAL) has become an increasingly important technique for metals production and metal oxides nanoparticles (NPs). This technique has its many advantages compared with other conventional techniques (physical and chemical). This work was devoted for production of alumina (Al2O3) nanoparticles via PLAL technique from a solid alumina target immersed in Distilled Wate...

The present work was focused on obtaining biocide coatings constituted by a glassy soda-lime matrix containing silver or copper nanoparticles on ceramic (alumina and zirconia based) substrates. Both glassy coatings showed a high biocide activity against Gram-, Gram+ bacteria and yeast, reducing cell numbers more than three logarithms. Silver nanoparticles had a significantly higher biocide acti...

γ-Alumina is widely used as an oxide support in catalysis, and palladium nanoparticles supported by alumina represent one of the most frequently used dispersed metals. The surface sites of the catalysts are often probed via FTIR spectroscopy upon CO adsorption, which may result in the formation of surface carbonate species. We have examined this process in detail utilizing FTIR to monitor carbo...

Nanoscale alloying and phase transformations in physical mixtures of Pd and Cu ultrafine nanoparticles are investigated in real time with in situ synchrotron-based x-ray diffraction complemented by ex situ high-resolution transmission electron microscopy. The combination of metal-support interaction and reactive/non-reactive environment was found to determine the thermal evolution and ultimate ...

Variable-temperature X-ray absorption spectroscopy measurements of sub-nanometer Pt nanoparticles on a high-surface-area gamma-alumina support reveal that the Pt-Pt bonds exhibit contraction upon heating [i.e., negative thermal expansion (NTE)]. Bare clusters under a He environment show an average linear expansion coefficient of -2.5 x 10-5 K-1 over the temperature range studied. Adsorption of ...

A taper-fiber SERS nanoprobe modified by gold nanoparticles (Au-NPs) with ultrathin alumina layers was fabricated and its ability to perform remote Raman detection was demonstrated. The taper-fiber nanoprobe (TFNP) with a nanoscale tip size under 80 nm was made by heated pulling combined with the chemical etching method. The Au-NPs were deposited on the TFNP surface with the electrostatic self-...

Ag and Ru nanoparticles stabilized by H5PV2Mo10O40, prepared by a sequence of redox reactions and supported on alpha-alumina, were effective catalysts for the direct aerobic epoxidation of alkenes in the liquid phase.