Characterization of sulfided molybdenum/alumina catalysts by temperature-programmed reduction and low-temperature Fourier transform infrared spectroscopy of adsorbed carbon monoxide

Sulfided Mo/Al[sub 2]O[sub 3] catalysts were studied by temperature-programmed reduction (TPRS) and transmission infrared spectroscopy of adsorbed CO at low temperatures. Reductive elimination of nonstoichiometric and stoichiometric sulfur from edge and corner sites creates coordinatively unsaturated Mo[sup 2+] sites. C-O stretching bands at 2100 cm[sup [minus]1] and at ca. 2060-2070 cm[sup [minus]1] were attributed to CO adsorption complexes on edge and corner sites, respectively. Evidence of morphological changes of MoS[sub 2] slabs during H[sub 2] treatment at 770 K is provided. IR spectroscopy of adsorbed CO at low temperature provides unique possibilities for the characterization of sulfided catalysts. 39 refs., 8 figs., 1 tab.