Acid-base characterisation of flat oxide-covered metal surfaces

This paper gives a brief description of the experimental methods which can be used to determine the main parameters characteristic of the acid/base properties of flat oxide-covered metal surfaces, either at a macroscopic scale (point of zero charge, isoelectric point, surface charge...) or at a molecular level (identification of the acid/base nature of the reaction sites, strengths of acid/base interactions...). It will be shown that, even though a global description of acid-base properties in terms of zero-point charge or isoelectric point might prove to be a useful parameter for characterisation of a solid surface, a localised description at an atom- or molecular-size of the nature and the strength of the reactive sites is required for the explanation of molecular events involved in the acid-base interactions. (C) 2002 Elsevier Science Ltd. All rights reserved.