III International Conference

PP-II-43-crucial role play peroxide ions O 2 involved in CO oxidation by not dissociating oxygenmolecules. The increase of the calcination temperature (in the range 60-600°C) decreases thecatalytic activity of gold supported catalysts in the CO oxidation reaction by oxygen, due totheir dehydration and gold sintering. The reduced by NaBH 4 gold/iron oxide supportedcatalysts seems resistant for overheating up to 500°C. Despite to many literature data chlorineions did not appear any poison for Au/support catalysts up to molar ratio Cl/Au = 8 and theinhibiting effect was observed for higher molar ratio causing a rapid drop of catalyst activity.The influence of support kind on the activity of supported gold catalysts in WGS reaction canby described by following order: TiO 2 > Fe 2 O 3 > Al 2 O 3 . The ineffective catalyst appearedAu/Al 2 O 3 which showed rather insignificant activity above 400°C, whereas the TiO 2supported catalysts showed WGS activity above 100°C.1002100CO Conversion%8060402013 41 - 5% Au (dep-prec + urea)2 - 5% Au (imp + KOH)3 - 5% Au (dep-prec)4 - 5% Au (imp)CO Conversion, %806040201321 - 5% Au (imp + KOH)2 - 5% Au (imp)3 - 5% Au (prec-dep)0-100 0 100 200 300 400 500Temperature, °C0-20 30 80 130 180 230Temperature, °C100280601 - 5% Au (prec-dep)2 - 5% Au (imp)3 - 5% Au (imp + KOH)13CO conversion %402000 50 100 150 200 250 300 350 400 450Temperature, °CThe influence of preparation method on CO conversion degree for Au/support (Al 2 O 3, TiO 2 ,Al 2 O 3 ) catalysts in carbon monoxide oxidation by oxygen.Conclusions: The prerequisite conditions of the highly active Au/support catalysts are:1. high degree of gold dispersion2. the reducible character of support surface Au/Fe 2 O 3 > Au/TiO 2 > Au/Al 2 O 33. high degree of the surface amorphization4. presence on the surface the strong base hydroxyl groups and O - 2 ions favored by K +ion additionAcknowledgements: The partial financial support of this work by the Polish ScientificResearch Council (Grant No. PBZ-KBN-116/T09/2004 (No. K124/1B/2005) is gratefullyacknowledged.243