At 298 K in IR cell Cd-zeolite wafers were contacted with acetylene and spectra were recorded. The reactions with zeolitic water resulted in formation of adsorbed acetaldehyde (AA, a) and secondary products. The rate of increase of the integrated intensities of bands stemming from the AA,a was used to deduce the reaction rate. The initial rates of formation of AA,a divided by the number of Cd2+ ions was used to characterise the intrinsic activity (IA) of the Cd2+ ions in the zeolitic environment. The zeolitic media was found to affect strongly the catalytic activity of the transition metal Cd2+ ion sites. IA was found to increase with the Si/Al ratio of the zeolite. Catalytic properties allowed to distinguish three groups of the preparations studied. Similarities were recognized in the coordination of Cd2+ ions in each member of a group. Data suggest that the IA of the Cd2+ ion within a zeolite is controlled by both coordination (structural) and electronic (compositional) effects.
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry