Silica films with controlled thickness and refractive index have been formed by the sequential adsorption of a cationic polyelectrolyte and silica sols. The conditions used to prepare the sol were varied, and allowed films with refractive indices as low as 1.16 to be obtained. The sequential adsorption technique allows the thickness of these films to be controlled in increments of 5-10 nm, depe...

Mesoporous TiO2 microspheres assembled from TiO2 nanoparticles with specific surface areas as high as 150 m(2) g(-1) were synthesized via a facile one-step solvothermal reaction of titanium isopropoxide and anhydrous acetone. Aldol condensation of acetone gradually releases structural H2O, which hydrolyzes and condenses titanium isopropoxide, forming TiO2 nanocrystals. Simultaneous growth and a...

The kaolinite/TiO2 composite (60 wt% of TiO2) was prepared by thermal hydrolysis of a raw kaolin suspension in titanyl sulphate and calcined at different temperatures (600, 650 and 700°C) and for different times (1, 2 and 3 h). The obtained samples were characterized by XRPD, N2 physical adsorption and SEM, and tested for photocatalytic reduction of CO2. The different calcination conditions did...

This article describes the solution-phase synthesis of 4 nm gold nanoparticles with 0.7 atom-thick, 1.9 atom-thick, and 3.8 atom-thick layers of Pd on their surfaces. These well-defined core−shell nanoparticles were deposited on a silica support, calcined, and reduced at 300 °C to create alloyed nanoparticles containing 10.9, 20.2, and 28.5% Pd (w/w). Monometallic Pd nanoparticles sintered duri...

In Pt/ZrO2 catalysts used for CO2/CH4 reforming to syngas, not all accessible Pt contributes equally to the activity of the catalyst. The catalytic activity is determined by the accessibility of Pt on the Pt-ZrO2 perimeter. This is explained in terms of the CO2 activation via carbonate species on the support which must be in the proximity of the Pt particles to react with the methane activated ...

Au/CeLaOx mixed oxide catalysts containing 0.5 to 1.0 wt% Au were prepared via coprecipitation with HAuCl4, the appropriate nitrate precursors, and either urea or Na2CO3 as the precipitant. BET surface area measurements for the Au/CeLaOx catalysts varied in the range of 16-107 m/g depending on the precipitant, aging time, and calcination conditions. The catalysts were tested for the selective o...

Electrospinning is a versatile technique, which can be used to generate nanofibers from a rich variety of materials. We investigate the variation of a zinc oxide (ZnO)-polyvinylpyrrolidone (PVP) composite structure in morphology by electrospinning from a series of mixture solutions of ZnO sol-gel and PVP. Calcination conditions for the crystallization of ZnO nanofibers and removal of the PVP co...

Zinc oxide (ZnO) photocatalysts were synthesized by sol-gel method using zinc acetate as precursor for degradation of azo dyes under UV irradiation. The resultant samples were characterized by different techniques, such as XRD, SEM, and EDX. The influence of preparation conditions such as calcination temperature and composite ratio on the degradation of methyl orange (MO) was investigated. ZnO ...

Methanobactin (Mb) is a copper-binding peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and reduce Au(III) to Au(0). In this paper, Au/Al2O3 catalysts prepared by a novel incipient wetness-Mb-mediated bioreduction method were used for glucose oxidation. The catalysts were characterized, and the analysis revealed that very small ...

1 The process at Holcim's Lägerdorf plant Objective: calciner temperature control There are many different recognized plant designs in cement production. Almost all the more recent energy­efficient plants now have a suspension preheater with several cyclone stages and a calciner in which the calcination (CaCO 3 → CaO + CO 2) of the raw meal takes place. Calcination of the raw meal in the calcin...