CoMo/alumina prepared from carbonyl precursors DRIFT, TPR and HDS studies

Mo(CO)(6) was deposited on alumina by gas phase adsorption in a fluidised b ed reactor. Samples were heated gradually to determine the thermal behaviou r of the surface species of molybdenum carbonyls. Mo(CO)(3)(ads) was identi fied as the most stable species, evidently appearing as two adsorption site s of different thermal stability. The IR spectrum recorded after deposition of Co-2(CO)(8) on Mo/alumina was the same as the IR spectrum of Co-2(CO)(8 ) on alumina. After decarbonylation at 200 degrees C, the nu(CO) bands due to the less stable of the Mo(CO)(3)(ads) species were better resolved when Mo(CO)(6) was deposited after decarbonylation of Co-2(CO)(8) on alumina, th an when it was directly deposited on alumina. temperature-programmed reduct ion demonstrated interactions between alumina supported molybdenum and coba lt species. Activity of the samples was tested in hydrodesulphurisation of thiophene using a batch reactor. n-Butane was the main product, and the thi ophene conversion was found to depend on the deposition order of the metals when the concentrations of the metals were similar. (C) 2000 Elsevier Scie nce B.V. All rights reserved.