The surface area of the al2o3 support was 305 m2g it

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Unformatted text preview: O\VW 7KH FDWDO\VW FRQVLVWHG RI  1L2 supported on Al2O3 and contained additionally 2% K2O. The surface area of the Al2O3 support was 30.5 m2/g. It was delivered as pellets after calcination at 450°C for 4 hours, reduction for 4 hours at 800°C and passivation. Before the catalytic tests it was crushed, sieved and reduced like the normal catalysts. 2.3. Elemental and structural analysis The metal content of all hydrotalcite-type solids was determined employing inductively coupled plasma atomic emission spectroscopy (ICP-AES, Perkin-Elmer P400). The carbon and nitrogen content was analysed by an elemental analyser (Carlo-Erba elemental analyser 1106). The amount of intercalated water was determined from the first weight loss during the calcination, measured by thermogravimetry coupled with fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff 2. Experimental 56 fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff mass spectroscopy (TG-MS) (Mettler Toledo Star TGA/SDTA 851e - Balzer GSD 300T3). The structure of all coprecipitated and all calcined solids was studied by means of Xray powder diffraction (XRD) (Siemens D500 diffractometer) using CuKα radiation (λ=0.15418 nm). A range from 8° to 70° was investigated at a scanning speed of 0.030°/s. The morphology of selected calcined samples was investigated by scanning electron microscopy (SEM) at 20keV (Joel JSM 6300). A detailed characterisation of the calcination process of all coprecipitated solids was performed by thermogravimetry combined with on-line analysis of the evolved gases by mass spectroscopy (TG-MS, described above) and by differential scanning calormetry (DSC) (Mettler Toledo Star DSC 821e). TG was performed in a flow of air up to 1100°C and DSC in a flow of Ar up to 600°C, both at a heating rate of 5°C/min. The BET surface area of the ca...
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