SOME PROBLEMS IN THE STUDY OF THE HETEROGENEITY OF SOLID-SURFACES

A brief review is given of the nature and origin of the heterogeneity of solid surfaces. Ways in which gas adsorption data can be used to characterize surface heterogeneity are discussed, and some of the problems of making a unique description are outlined. These problems are illustrated using data on the adsorption of Xe and CO2 by an active carbon over a wide temperature range. The application of measurements of adsorption from solution and enthalpies of immersion to the elucidation of heterogeneity faces similar problems which have yet to be resolved satisfactorily. The role of surface heterogeneity in catalytic processes at solid surfaces remains largely unresolved.