CO adsorption on supported Pd catalysts studied by adsorption microcalorimetry
and temperature programmed desorption
Applied Catalysis A: General, (1997)DOI: 10.1016/S0926-860X(96)00418-8
Abstract
The adsorption of CO on silica-, alumina- and titania-supported Pd
catalysts (2, 5, and 10 wt% Pd) has been studied by adsorption microcalorimetry
and temperature programmed desorption (TPD) experiments in a flow
system at atmospheric pressure. On supported Pd catalysts, bridge-bonded
CO was found to be the dominant CO(ads) species. The observed influence
of Pd loading on CO adsorption energetics was explained in terms
of particle size and/or surface structure of the Pd crystallites.
Support materials can be divided into active (TiO2, Al2O3) and inert
(SiO2) supports, where Pd catalysts with active supports are characterized
by (1) an increased sensitivity of CO adsorption to reduction temperature,
(2) promotion of CO dissociation, and (3) an increased activity of
surface carbon towards hydrogenation, as compared to Pd catalysts
supported on inert silica.