Applied Surface Science, Vol.253, No.6, 3215-3230, 2007
Relationships between surface compositions and properties of surfaces of mixed fumed oxides
Fumed oxides SiO2/Al2O3 (SA), SiO2/TiO2 (ST) and Al2O3/SiO2TiO2 (AST) at different content of alumina and titania were investigated by one-pass temperature-programmed desorption (OPTPD) time-of-flight mass-spectrometry (TOFMS), Auger electron spectroscopy (AES), NMR, FTIR, thermally stimulated depolarization current (TSDC), microcalorimetry, adsorption of nitrogen, water, (dimethylamino)azobenzene (DMAAB) and metal ions (Pb(II) and Ni(II)). It was shown that all the studied adsorption/desorption and energetic properties of mixed fumed oxides depend strongly on the surface content of alumina Cs-Al2O3 (shown as a surface content of aluminum, in SA and AST and titania C-Tio2(s) (shown as a surface content of titanium, C-Ti(s)) in ST and AST. Many of these properties demonstrate clear correlations with the C-Al(s) and C-Ti(s) values over the total range of alumina and titania content in the materials. (c) 2006 Elsevier B.V. All rights reserved.
Keywords:fumed SiO2/Al2O3;fumed SiO2,/TiO2;fumed Al2O3/SiO2/TiO2;Auger spectroscopy;NMR;FTIR;one-pass temperature-programmed electron desorption time-of-flight mass-spectrometry;nitrogen adsorption;water adsorption/desorption;(dimethylamino)azobenzene adsorption;Pb(II) adsorption;Ni(II) adsorption;surface hydroxyls;Debye screening length