Showing papers on "BET theory published in 1983"
TL;DR: In this article, the point of zero charge (p.z.c) of RuO2 powders prepared by thermal decomposition of RuCl3 at 300-700°C has been measured by potentiometric titration in KNO3 solutions.
70 citations
TL;DR: In this article, high-purity AlF3 has been prepared by allowing γ-Al2O3 to react with gaseous trifluoromethane at 670-770 K under 101 kPa total pressure.
49 citations
TL;DR: In this paper, a study of the preparation of ruthenium powder catalysts from various sources was made, and it was found that the extent of the chemisorbed hydrogen monolayer is lower than expected on the grounds of the BET surface area of the powder.
33 citations
TL;DR: The physical state of the material obtained during the various stages of preparation of a typical MgCl2-supported, high-mileage propylene polymerization catalyst was studied by BET, mercury porosimetry, and x-ray diffraction techniques.
Abstract: The physical state of the material obtained during the various stages of preparation of a typical MgCl2-supported, high-mileage propylene polymerization catalyst was studied by BET, mercury porosimetry, and x-ray diffraction techniques. The starting MgCl2 and the substance after HCl treatment have negligible BET surface areas. Mercury porosimetry showed that they have large pores with radii > 200 nm which are probably crevices between MgCl2 crystallites. The most pronounced physical changes occur during dry porcelain ball milling in the presence of ethyl benzoate. After 60 h or more of ball milling the material had a 5.1–7.3 m2 g−1 BET surface area, twice the pore surface area, and a smaller pore radius than before ball milling and a large reduction in crystallite sizes to almost ultimate dimensions. The crystallites were probably held together by complexation with ethyl benzoate in the form of large agglomerates. Subsequent reactions with p-cresol and triethyl aluminum had minor effects in further reduction of the MgCl2 crystallite size but efficiently brokeup the agglomerates. The final refluxing with TiCl4 increased the BET surface area to 110–150 m2 g−1 but may have increased the crystallite size somewhat due to cocrystallization of TiCl3 and AlCl3 with MgCl2. There may have been only 8–10 crystallites in each catalyst particle. The surface structure of the catalyst resembled those of the classical Ziegler-Natta γ-TiCl3·0.33 AlCl3 catalyst.
28 citations
TL;DR: In this paper, the formation of Pd complexes in phosphinated polystyrene resins has been studied, and it is shown that, depending on polymer properties such as the BET surface area and phosphine content, varying amounts of the complex Cl2Pd(pyridine)(PPS)1 are formed in the resin, together with the complex C 2 Pd(P ǫ )2.
20 citations
TL;DR: In this paper, the number of active oxygen species (Os) on the surface of Cr2O3 catalysts was determined by using the rectangular pulse technique coupled with the reaction of NH3 with a preoxidized catalyst.
17 citations
TL;DR: In this article, a good correlation was found between apparent BET surface area and total pore volume determined for a number of active charcoals by measurement of the nitrogen adsorption isotherms at 77 K.
16 citations
TL;DR: In this paper, the effect of heat treatment of five synthetic MnO 2 samples of various crystalline modifications on their O/Mn ratio, electrochemical activity (depolarising capacity), initial rate of catalytic decomposition of H 2 O 2 and BET surface area has been investigated.
13 citations
TL;DR: In this article, an amorphous precursor of spherical shape was formed from the gel mixture within three days, and intergrowth of zeolite crystals occurred in the spherical precursor.
12 citations
TL;DR: In this article, active γ-aluminas were prepared by thermolysis of hydrated aluminium nitrate, hydrated aluminum sulphate and ammonium alum at 1173 K. The specific surface area, pore volume and pore texture of these aluminas are determined by analysis of the corresponding nitrogen adsorption-desorption isotherms at 77 K.
9 citations
TL;DR: In this paper, the effect of parameters such as temperature, gas flow rate, oxygen concentration and oxychlorination on the sintering of an industrial bimetallic reforming catalyst (Pt-Ir/μ.Al2O3) during regeneration were investigated.
Patent•
18 Jul 1983
TL;DR: In this article, the authors proposed a method to produce carbon fiber with fine pore opening on the fiber surface in which the void volume of the pores with pore diameters of 200-10,000Angstrom is larger than 0.1cc/g, with a BET surface area of 1-20m /g and a void volume reduction of lower than 1.08cc /g, when dried at 120 deg.C for 1hr, are preoxidized and subjected to oxidative pore-opening treatment in an oxidaive atmosphere at over 500 deg
Abstract: PURPOSE:Fibers in which the pores have a specific void volume and BET surface area and the reduction in the void volume is low, when dried, is preoxidized, then subjected to oxidative pore-opening treatment under an oxidative atmosphere to produce the titled fiber that is suitable for use in uranium recovery, because of its large surface area and high strength. CONSTITUTION:Porous fibers that have fine pores opening on the fiber surface in which the void volume of the pores with pore diameters of 200-10,000Angstrom is larger than 0.1cc/g, a BET surface area of 1-20m /g and have the void volume reduction of lower than 0.08cc/g, when dried at 120 deg.C for 1hr, are preoxidized and subjected to oxidative pore-opening treatment in an oxidaive atmosphere at over 500 deg.C to give the objective carbon fiber with a pore volume of pores of 200-10,000Angstrom 0.1cc/g larger than.
TL;DR: In this paper, the aerosil 200 was thermally dehydrated in vacuo at various temperatures in the range 20-1000 °C and the results showed that the surface area increases by pore narrowing and vice versa.
TL;DR: In this article, the effects of thermal treatment on water loss and content, specific surface areas (as measured by cyclohexane vapour adsorption) and heats of immersion in liquid cyclomethane are presented and discussed.
TL;DR: In this article, the surface area and pore properties of composites of magnesia-alumina-aluminum phosphate have been examined as a function of preparation parameters, such as pH and calcination temperature.
Abstract: The surface area and pore properties of composites of magnesia-alumina-aluminum phosphate have been examined as a function of preparation parameters Sufficiently good correlations were obtained between the composition and the BET surface area, average pore size and median pore size, so that empirical models could be constructed to predict these properties with a reasonable degree of confidence Pore volume was found to be independent of composition Other preparation variables, such as pH and calcination temperature, were examined and these were found to only slightly influence the characteristics of the finished product