Supports/catalysts after calcination pore, diameter

BET Surface Area, Pore Volume, and Average Pore Diameter of the Supports and Catalysts after Calcination at 623 K... 

Table 1. BET surface area, mean pore diameter, and pore volume for the supports and catalysts after calcination. For the nitrogen sorption data, the experimental error ( 2ff) is 5 m /g for the surface areas, 0.2 nm for the mean pore diameters, and 0.02 cm /g for the pore volumes.

Catalyst preparation. Chloroplatinic acid, in such amounts as to obtain the desired concentration of Pt in the catalysts, was added to previously prepared w/o microemulsions. Two types of catalytic supports, y-alumina in the form of full pellets (diameter 5 mm) and 0-alumina in the form of hollow pellets (diameter 5 mm, hole 2 mm), both manufactured in Chemopetrol Litvinov, Czech Republic, were chosen for catalysts preparation. After calcination at 500 °C y-alumina had Sbet=166 m /g, pore volume 0.459 ml/g, mean pore radius 7.0 nm and water absorption capacity 40 %. After calcination at 900 °C 0-alumina showed Sbet=145 m /g, pore volume 0.445 ml/g, mean pore radius 8.1 nm and water absorption capacity 50 %. The catalysts with 0.3 and 0.1 wt. % Pt were prepared by impregnation with HaPtCle water solutions (denoted as I) or Pt microemulsions (denoted as M). The catalysts were dried 2 h at 120-160°C and calcined 2 h in air at 550 °C. Characterization of microemulsions... 

Fig. 3 depicts the N2 adsorption-desorption isotherms (A) and pore size distribution (B) of the samples. The shape of the isotherms (Fig. 3A) and the pore sizes did not change significantly (Table 1), meaning that material kept its mesoporous structure after introduction of the ceria. The pore diameters of the support and the gold loaded catalysts, both calcined at 400 °C, are practically... 

Various promoted Ni/MgO catalysts have been prepared by multiple successive impregnation of the MgO support. Tlie support used, which was calcined at 1450°C, had the following characteristics macroporous spherical granules having diameter of about 20 mm, BET surface area of 0.25 m and specific pore volume of 0.145 cmV -Aqueous solutions of Ni-nitrate and nitrate of the corresponding promoter, with atomic ratio 10 1, respectively, were used. All the impregnation steps were performed at 25°C, with the ratio of solution volume to support mass of 3 cmV. and the solution/support contact time of 30 min. After each impregnation the catalyst precursors were subsequently dried at 110°C for Ih and calcined at 400°C for 2h to convert nitrate salts onto oxides. 

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