The adsorption of CO on alumina-supported Rh of different crystallite sizes produced by reduction at 573-1273 K has been investigated by following the development of the infrared bands due to Rh1(CO)2 and Rh-CO species. It is concluded that the effect of CO on the state of the dispersed Rh is a twofold one. In harmony with recent EXAFS measurements of Prins et al., CO adsorption at around 300 K leads to disruption of the Rh clusters and to the formation of isolated Rh1 sites, as indicated by the slow development of the infrared bands of gem-dicarbonyl. Above 423 K, another effect of adsorbed CO comes into prominence, which leads to the formation of Rh crystallites at the expense of isolated Rh1 sites. It is demonstrated that the formation of isolated Rh1 sites occurs more slowly under dry conditions.
|Number of pages||5|
|Journal||Journal of physical chemistry|
|Publication status||Published - Dec 1 1985|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry