The interaction of oxygen with a silver catalyst containing isolated silver particles of ca. 70 nm supported on a-Al,O, has been studied using (combined) volumetric adsorption and temperature-programmed desorption measurements after various pretreatments. The amount of oxygen taken up is greatly influenced by the pretreatment. Considerable amounts of oxygen are able to penetrate into the silver lattice. Impurities present in or on the silver particles strongly affect the amount of oxygen taken up at 443 K. It is argued that penetrated oxygen can facilitate the reorganization of the silver surface giving rise to low-index facets. Plate 1. A representative SEM micrograph of the catalyst.

In order to elucidate the influence of the pretreatment on the (catalytic) properties of silver catalysts containing large silver particles ( & 1 pm), the interaction of oxygen and hydrogen with reduced and pre-oxidized samples has been investigated. The effect of the presence of caesium on the silver surface has also been investigated. Volumetric (ad)sorption of oxygen and hydrogen, TPD experiments, corn bined with chemisorption measurements, and electron microscopy were used as characterization techniques.