Spilt-over hydrogen is known to have a strong effect on the catalytic reaction on sold acid catalysts. Under a hydrogen atmosphere, the catalyst prepared by the physical mixture of Pt/SiO2 and H-ZSM-5 was very effective for the hydroisomerization or the hydrocracking of n-pentane, n-hexane, and other paraffinic hydrocarbons under a hydrogen atmosphere. FTIR and TPD were used to study the influence of spilt-over hydrogen on catalysts that were prepared by physically mixing zeolites or alumina with SiO2-supported noble metals on chemisorbed pyridine. Pyridine adsorbed on a Lewis acid site migrated to a Broensted acid site under a hydrogen atmosphere. This signified that spilt-over hydrogen should increase the desorption on the Lewis acid site, and that the possible state of spilt-over hydrogen on the Lewis acid site should be hydride, which has strong Lewis basicity. H-D exchange (-OH + D2) of the Broensted acid site was also conducted, which resulted in a complete description of interactions between spilt-over hydrogen and acid sites of zeolite.
- Bronsted and Lewis acid sites
- Hybrid catalyst
- Hydrogen spillover
- Proton and hydride
- Pyridine migration
ASJC Scopus subject areas
- Physical and Theoretical Chemistry