Structure and Catalytic Testing of Hybrid Al2O3 Systems Deposited on Heat Resisting Steel Substrate by High-Temperature Oxidation and PVD Methods
Catalytic combustors for automotive presents a basic problems with obtaining the well developed oxide surface marked by the occurrence of acidic and basic sites and performing the function of the catalytic element carrier. The paper includes the comparison of structure and catalytic properties of: - Al2O3 films obtained by oxidizing the foil made of 0H18J5 alloy in the presence of SO2, at the 1093K , - Al2O3 films obtained by oxidizing the foil, coated firstly with an Al film, in the presence of Ar+50%O2 at the 1133K, - Al2O3 film systems obtained by oxidizing the foil in the presence of Ar+50%O2 at the 1133K, then coated an Al nano-film and again oxidized under the same conditions, - Al2O3 film systems obtained, as previously, by oxidizing the foil, which was firstly coated with an Al2O3 nano-film by reactive magnetron sputtering. The catalytic activity of deposited films was determined from the basic sites identified by 2-methylol-3-butyn-2-ol conversion into acetone and acetylene, and from the acidic sites identified by its dehydration into 2- methylol-1-buten-3-yn.The structure analysis of the oxide films obtained by oxidizing under SO2 revealed the occurrence of θ-, γ- and α-Al2O3 phases, however the oxide films obtained by oxidizing the foil with an Al precursor in the presence of Ar+50%O2 contained a small amount of hematite. The catalytic test revealed that the films containing θ- and γ -Al2O3 have acidic and basic sites and their catalytic activity is high, whereas α-Al2O3 and amorphous films do not show such the activity.
K. Reszka "Structure and Catalytic Testing of Hybrid Al2O3 Systems Deposited on Heat Resisting Steel Substrate by High-Temperature Oxidation and PVD Methods", Advances in Science and Technology, Vol. 45, pp. 2110-2117, 2006