Nanocrystalline a-Al 2 O 3 and Ni-modified a-Al 2 O 3 have been prepared by sol-gel and solvothermal methods and employed as supports for Pd catalysts. Regardless of the preparation method used, NiAl 2 O 4 spinel was formed on the Ni-modified a-Al 2 O 3 after calcination at 1150 8C. However, an addi
Pt and Pd catalysts supported on Al2O3 modified with rare earth oxides in the hydrogenation of tetralin, in the presence of thiophene
✍ Scribed by Denise Sousa Brandão; Rosana Machado Galvão; Maria da Graça; Martins Carneiro da Rocha; Pascal Bargiela; Emerson Andrade Sales
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 708 KB
- Volume
- 133-135
- Category
- Article
- ISSN
- 0920-5861
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✦ Synopsis
Due to stringent environmental regulations, the reduction of aromatic compounds present in diesel fuel, precursors of particulate matter, is becoming one of the most important technologies in petroleum refining industries. However, the high quantity of nitrogen and sulfur compounds limits the use of catalytic processes. In this work Pt and Pd catalysts supported on alumina modified with rare earth oxides (Ce and Pr) were prepared, characterized by XRF, XRD, UV-vis-DRS and XPS, and tested in the hydrogenation of tetralin reaction, in the presence of different concentrations of thiophene. The results showed that the use of a Pr-modified alumina support enhanced the tolerance of the Pt/Al 2 O 3 catalyst to thiophene. The addition of a second metal, Pd, despite a loss in activity, increased tolerance to this poison. The combination of both promoters exhibited a synergic effect, as the bimetallic catalyst supported in the Pr-modified alumina showed a very low sensitivity to thiophene, up to 2600 ppm, explained by the electron-deficiency of the metallic Pt.
📜 SIMILAR VOLUMES
## Abstract A series of cobalt‐molybdenum‐alumina catalysts was fabricated using as carriers λ‐Al~2~O~3~ doped with various amounts of sodium. Over these surfaces the H.D.S. of thiophene has been studied. A considerable decrease in the catalytic activity was observed with increasing Na^±^ content.