A series of zirconia supported molybdenum catalysts were prepared and chara
cterized by BETSA, XRD, TPR, FTIR, XPS and oxygen chemisorption. Thiophene,
cyclohexene and tetrahydrofuran were taken as model compounds for evaluati
ng their hydrodesulfurization (HDS), hydrogenation (HYD) and hydrodeoxygena
tion (HDO) activities, respectively. The XRD results indicate that Mo is pr
esent as a monolayer up to 6 wt.%; loading, whereas MoO3 crystalline growth
is observed beyond this loading. O-2-uptalie and catalytic activities also
increase up to 6 wt.% Mo-loading but above this loading both start decreas
ing. There are good correlations between O-2 uptake and all catalytic activ
ities. TPR and FTIR results indicate that at lower loading, MoO3 is present
as tetrahedra form and at moderate loading, both tetrahedral and octahedra
l forms are found. XPS results reveal that the electron transfer is taking
place from support to molybdenum. (C) 2000 Elsevier Science B.V. All rights
reserved.