DECOMPOSITION OF MOLYBDENUM HEXACARBONYL DEPOSITED ON DEHYDROXYLATED ALUMINA

Abstract

Deposition and decomposition of Mo(CO)6 on dehydroxylated alumina was studied by XAFS, The rate of deposition and the structure of deposited species depended on deposition temperature. In the deposition at 320 K, the rate was slow and the species on the support was found to be Mo(CO)5. The species formed at 360 K had an average stoichiometry of Mo(CO)2.5 without well-defined structure. Heating of the deposited subcarbonyls in flowing H-2 caused first simple decarbonylation and then methanation above 450 K. Around 930 K, highly carbon deficient Mo2C was formed which was converted to metallic Mo upon further heating to 970 K.