Oxygen adsorption on Ag powder

Abstract

Oxygen adsorption on a Ag powder sample is different from that on a supported Ag catalyst. The powder shows the presence of a very high temperature desorption state (at 900 K) which diminishes adsorption into the state which is common to all types of silver samples (desorption peak at 560 K). This behaviour, together with the increased sticking probability which is observed on the powder, indicates that the powder has a very much rougher surface structure than a catalyst, which consists of mostly (111) planes. The powder probably consists of a high proportion of (111) planes with a high density of steps and defects since the high-temperature desorption state has been seen on a stepped single-crystal plane [Ag(331)].