Hydrogen adsorption sites studied by carbon monoxide adsorption to explain the hydrogenation activity of benzene on Pd and Pt catalysts

FT-IR of CO has been employed to study the relations between hydrogen adsorption and benzene hydrogenation on Pd/SiO 2 and Pt/SiO 2 catalysts. Three IR bands of CO stretching: 2085 (L 1 band), 1984 (B 1 band) and 1948 cm −1 (B 2 band), have been observed on Pd/SiO 2. Hydrogenation of benzene is domi...

Full description

Saved in:
Bibliographic Details
Published in:Applied catalysis. A, General General, 2006-01, Vol.298, p.161-167
Main Authors: Chen, Ching-Shiun, Lin, Jarrn-Horng, Chen, Hsiu-Wei
Format: Article
Language:English
Subjects:
Benzene hydrogenation
Catalysis
Chemistry
CO adsorption
Exact sciences and technology
General and physical chemistry
IR spectra
Palladium
Platinum
Surface physical chemistry
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:FT-IR of CO has been employed to study the relations between hydrogen adsorption and benzene hydrogenation on Pd/SiO 2 and Pt/SiO 2 catalysts. Three IR bands of CO stretching: 2085 (L 1 band), 1984 (B 1 band) and 1948 cm −1 (B 2 band), have been observed on Pd/SiO 2. Hydrogenation of benzene is dominated by hydrogen adsorption on B 1 sites (CO band at 1984 cm −1) of Pd/SiO 2, because benzene and/or the benzene ring of acetophenone can preferentially cover on the B 1 sites to hinder hydrogen adsorption, leading to poor catalytic activity for hydrogenation of benzene. When hydrogen is pre-covered on Pd/SiO 2 to occupy the B 1 sites, it will cause intense benzene hydrogenation. Pre-adsorbed acetophenone on Pt/SiO 2 surface presents a surprising phenomenon that adsorbed acetophenone does not impede CO adsorption. We propose that adsorption of hydrogen is independent of the exposure of pre-adsorbed acetophenone, and therefore Pt/SiO 2 catalyst can offer high catalytic activity for hydrogenation of benzene.
ISSN:0926-860X
1873-3875
DOI:10.1016/j.apcata.2005.09.036