So-called “Co-Mo-S” phase observed in carbon-supported Co and Co-Mo sulfide catalysts by Mössbauer emission spectroscopy

Abstract

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Sulfidation of alumina-supported iron and iron-molybdenum oxide catalysts

“…It seemed unlikely that the surface-oxide phase should remain nearly unaffected by such a treatment in H,S/H,, while already at room temperature iron sulfides are formed in these catalysts [ 91. Furthermore, recently Van der Kraan et al [30,31] have reported a similar quadrupole splitting as ascribed to the "CO-MO-S" phase by Topsare et al…”

Evaluation of the maximum potential activity of Co–Mo/Al2O3 catalysts for hydrodesulfurization

“…Based on the MES and XAFS studies of supported CoMo catalysts, Crajé et al [31,35,36] and van der Kraan et al [37] proposed a sophisticated surface model of the catalysts, in which highly dispersed Co sulfide particles are located at the edge positions of MoS 2 crystallites and the size of the Co sulfide particles decreases as the Co/Mo ratio decreases. The blocking of the edges of MoS 2 particles by Co sulfide clusters can be easily explained by their surface model.…”

Thermal Stability of the Co−Mo−S Structure As Studied by a CVD Technique Using Co(CO)3NO

“…The blocking mechanism has been previously proposed to explain lower HDS activities of Co−Mo/Al 2 O 3 impregnation catalysts compared to the activity of Co/MoAl . On the basis of Mössbauer emission spectroscopy and XAFS studies of supported Co−Mo catalysts, Crajé et al and van der Kraan et al proposed that small cobalt sulfide clusters in contact with the edges of MoS 2 particles generate catalytic synergies between cobalt and molybdenum sulfides. However, it appears that the present and previous activity results can be simply explained by blocking of the MoS 2 edge sites and, accordingly, the Co−Mo−S structure by cobalt sulfide clusters.…”