Use of XPS in the determination of chemical environment and oxidation state of iron and sulfur samples: constitution of a data basis in binding energies for Fe and S reference compounds and applications to the evidence of surface species of an oxidized pyrite in a carbonate medium

This paper presents a report on the XPS coherent binding energy (BE) data basis for iron and sulfur reference compounds that are representative of oxidation products formed onto the pyrite reactive surface. This work is unique for various reasons: (1) no recent (published after 1980) BE data basis with similar normalization method has been found in the literature; (2) the coupling of data collected from Fe and S photoelectron peaks and from charge transfer satellites of Fe allows for the simultaneous determination of the oxidation state and chemical environment; (3) the depth heterogeneities of samples can be taken into account by comparing the data obtained with Fe2p and Fe3p peaks, whose associated BEs are widely divergent. In the second part of the paper, the data in BEs obtained from reference compounds have been exploited to show the surface species of an oxidized pyrite in a HCO3- medium (10(-2) M). (C) 2000 Elsevier Science B.V. All rights reserved.