Abstract
Quantitative electron spectroscopy for chemical analyses (ESCA) of bitumen-processing catalysts, ESCA analyses of the surfaces of 18 pelleted MoO/sub 3//A1/sub 2/O/sub 3/ hydrodesulfurization catalysts, with and without CoO or NiO promotors, and before and after sulfiding, all prepared by impregnating the components on aqueous A100H gels and calcining, were compared with bulk compositions determined from the preparation and by ESCA analysis of ground samples.In general, the three composition measurements agreed with each other within 5% before sulfiding, but ESCA analyses of sulfided catalysts showed systematically low values for molybdenum, cobalt, and nickel. Unsatisfactory agreement between the ESCA and ''chemical'' compositions was also found for five commercial catalysts; in particular one commercial Ketjen catalyst had an apparent exterior surface Mo concentration about five times that of the chemical bulk and ESCA bulk compositions. This is attributed to the different methods of preparation of the commercial and laboratory catalysts; possible aggregation of MoO/sub 3/, NiO, and CoO particles took place in the commercial catalysts.
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