Relationships between surface compositions and properties of surfaces of mixed fumed oxides

Fumed oxides SiO2/Al2O3 (SA), SiO2/TiO2 (ST) and Al2O3/SiO2/TiO2 (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, Cs Al) in SA and AST and titania Cs TiO2 (shown as a surface content of titanium, Cs Ti) in ST and AST. Many of these properties demonstrate clear correlations with the Cs Al and Cs Ti values over the total range of alumina and titania content in the materials