Preparation of Pd-Pb/α-Al2O3 catalysts for selective hydrogenation using PbBu4 : the role of metal-support boundary atoms and the formation of a stable surface complex

• Published in: Catalysis letters 1999-01, Vol.61 (1-2), p.27-32
• Main Authors: VOLPE, M. A, RODRIGUEZ, P, GIGOLA, C. E
• Format: Article
• Language: English
• Subjects: Acetylene; Aluminum oxide; Anchoring; Catalysis; Catalysts; Catalysts: preparations and properties; Chemistry; Exact sciences and technology; General and physical chemistry; Hydrogen storage; Hydrogenation; Palladium; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1023/A:1019087814472

Pd–Pb/α-Al2O3 catalysts were prepared by reacting PbBu4 with supported palladium samples derived from Pd(AcAc)2, both in the presence and absence of hydrogen. The amount of lead fixed depends mainly on the concentration of palladium on the metal–support boundary. In the presence of hydrogen, all butyl groups are released during the anchoring process. When the Pd/α-Al2O3 was reduced and then purged with nitrogen, two butyl groups remained attached to the lead atom and a stable surface complex was formed. The analysis of gaseous products evolved during the PbBu4–Pd/α-Al2O3 interaction and subsequent temperature‐programmed reaction experiments indicate that a (]‐L)2–Pb(Bu)3 complex was obtained. Upon reduction at 573 K, the Pd–Pb/α-Al2O3 catalysts became very selective for the hydrogenation of acetylene in the presence of ethylene.