THE COBALT-MOLYBDENUM INTERACTION IN COMO SIO2 CATALYSTS - A COOXIDATION STUDY/

The interaction among cobalt, molybdenum and silica in CoMo/SiO2 catal ysts has been investigated in a series of catalysts with the same over all composition and varying interaction among the components. XRD and DRIFTS give a rough indication of the phases present, and the formatio n of CoMoO4 can be easily monitored. The formation of CoMoO4 is observ ed in most of the catalysts due to the poor interaction between molybd enum oxide and silica. The presence of other minor, non-crystalline ph ases must be attested by other methods, such as, TPR and catalytic oxi dation of carbon monoxide. The presence of ''free'' cobalt can be demo nstrated by a low temperature peak in TPR. The catalytic oxidation of CO may function as a useful indicator for the interaction between coba lt and molybdenum, because the oxidation activity of cobalt species in corporated in a molybdate lattice (i.e. CoMoO4) is considerably less t han cobalt oxide.