Effect of basic additives on Pt/Al{sub 2}O{sub 3} for CO and propylene oxidation under oxygen-deficient conditions
- National Central Univ., Chung-Li (Taiwan, Province of China). Dept. of Chemical Engineering
Pt catalysts supported on Al{sub 2}O{sub 3}, CeO{sub 2}/Al{sub 2}O{sub 3}, Na{sub 2}O/Al{sub 2}O{sub 3}, and K{sub 2}O/Al{sub 2}O{sub 3} were prepared and characterized with respect to surface area, CO chemisorption, temperature-programmed desorption (TPD) of CO{sub 2}, and temperature-programmed reduction (TPR) of H{sub 2}. The effects of basic additives on Pt/Al{sub 2}O{sub 3} for CO and propylene oxidation were investigated. The addition of basic additives slightly decreases the surface area of the catalyst and does not significantly change Pt dispersion. The basicity of the catalyst is in the order Pt-K{sub 2}O/Al{sub 2}O{sub 3} > Pt-Na{sub 2}O/Al{sub 2}O{sub 3} > Pt-CeO{sub 2}/Al{sub 2}O{sub 3} > Pt/Al{sub 2}O{sub 3}. The promoted Pt/Al{sub 2}O{sub 3} catalysts are much more active than the unpromoted one for CO and propylene oxidation under the stoichiometric point. Under oxygen-deficient conditions and in the absence of water, propylene conversions on all catalysts studied herein increase with increasing reaction temperature. Pt/Al{sub 2}O{sub 3} exhibits the highest propylene conversion and the lowest CO conversion among these catalysts, and the addition of CeO{sub 2}, Na{sub 2}O, and K{sub 2}O on Pt/Al{sub 2}O{sub 3} can promote the CO conversion. Under oxygen-deficient conditions and in the presence of water, the water-gas shift and steam re-forming reactions can take place and result in increases of CO and propylene conversions. Pt/Al{sub 2}O{sub 3} is the most active catalyst for the steam reforming reaction and the least active catalyst for the water-gas shift reaction among these catalysts. However, the addition of basic additives on Pt/Al{sub 2}O{sub 3} catalyst can significantly enhance the water-gas shift reaction that can reduce CO emission. The promotional effect is in the order K{sub 2}O > Na{sub 2}O > CeO{sub 2}. K{sub 2}O could be a promising additive to a catalytic converter of a two-stroke motorcycle since it can enhance CO conversion.
- Sponsoring Organization:
- National Science Council, Taipei (Taiwan, Province of China)
- OSTI ID:
- 509528
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 36, Issue 5; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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