High-thiotolerant Pt-Ge/Al{sub 2}O{sub 3} naphtha reforming catalysts by in-situ alloying
- Instituto de Investigaciones en Catalisis y Petroquimica, Santa Fe (Argentina)
The effect of alloying on the generation of high-thiotolerant Pt-Ge/Al{sub 2}O{sub 3} naphtha reforming catalysts was studied. The state of the metallic fraction after successively reducing the bimetallic catalyst with H{sub 2} at 300{degrees}C and 500{degrees}C was characterized by a variety of physical, spectroscopic, and catalytic techniques. It was found that the high-temperature treatment reduces a part of germanium cations to metallic Ge and forms Pt-Ge alloy clusters. In such alloyed bimetallic particles, Ge acts as an electron-acceptor element, decreasing the electronic density of platinum. Alloying diminishes dramatically both the H{sub 2} uptake and the activity for dehydrogenation reactions but, on the other hand, clearly enhances the resistance to sulfur poisoning. Catalyst thiotolerance is increased because alloying weakens the strength of the S-Pt bond and thereby reduces the amount of irreversibly held sulfur on platinum. It was found that the alloy formation is reversible when the catalyst is submitted to oxidation-reduction cycles. Although treatment with an oxidizing atmosphere at 450{degrees}C destroys the alloyed bimetallic particles, subsequent reduction with H{sub 2} at 500{degrees}C restores the Pt-Ge alloying and enhances the catalyst thiotolerance.
- OSTI ID:
- 468031
- Report Number(s):
- CONF-960652-; TRN: 96:004817-0068
- Resource Relation:
- Conference: 11. international congress on catalysis (ICC-11), Baltimore, MD (United States), 30 Jun - 5 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of 11th International congress on catalysis - 40th anniversary. Part A and B; Hightower, J.W.; Delgass, W.N.; Iglesia, E.; Bell, A.T. [eds.]; PB: 1482 p.
- Country of Publication:
- United States
- Language:
- English
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