Sulfur coverage and structural disorder in γ-alumina-supported MoS2 crystallites: an in situ EXAFS study

Abstract

Mo K-edge EXAFS spectra were recorded for a 6 wt.% Mo/Al₂O₃ hydrodesulfurization catalyst submitted to three gas treatments, where the ratio H₂S/H₂ was varied. The spectra were strongly influenced by the surrounding conditions. To fit them, the sulfur coverage of the platelets obtained by ab initio calculations was taken into account. The study of the fits also gave experimental evidence of the influence of the distortions on the calculation of the size of MoS₂ hexagonal crystallites. Comparison between the theoretical sulfur coverages and the EXAFS results were also examined in terms of the triangular model of MoS₂ platelets.