Spectroscopic and surface potential variations study of a CuCe oxide catalyst using H2S as a probe molecule

X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), electron paramagnetic resonance (EPR) and surface potential variations were used to study the reactivity of H2S on CuCe oxide catalyst. In the fresh catalyst, Cu2+ ions are present as monomers, dimers and clusters. After the H2S treatment at 293 K, all the Cu2+ species of catalyst become reduced. Such a reduction is irreversible even in the presence of oxygen. In parallel, S2- and SH- groups associated with copper in CeO2 are formed. Sulphide groups are stable and cannot be removed by further O-2 treatment. The valence of Ce(IV) is not affected with this H2S treatment. (C) 1999 Elsevier Science B.V. All rights reserved.