Catalytic chemistry of transition metal ions on oxide surfaces. A molecular approach using EPR techniques

The applications of EPR spectroscopy to the study of catalysis and surface chemistry of oxides are reviewed. The specific features of the EPR spectra of catalytic materials are described and the means employed to enhance the amount of information that can be extracted from the spectra are discussed. Selected recent examples illustrate the possibilities offered by EPR techn iques to the understanding of catalyst preparation of the nature of active sites and reaction intermediates 35 well as of catalytic rcaction mechanism s. One of the advantages of EPR is the possibility to investigate electron transfer phenomena (metal to ligand, ligand to metal or ligand to ligand) o ccurring between thr surface transition metal ions and the adsorbed molecul es. (C) 2000 Academic des sciences / Editions scientifiques et medicales El sevier SAS.