Reduction and metathesis activity of MoO3/Al2O3 catalysts: I. An XPS investigation of MoO3/AI2O3 catalysts

摘要: Abstract MoO 3 /Al 2 O catalysts (2–13 wt% ) were investigated by XPS in the oxidized form, after thermal treatment flowing Ar (973 K), and reduction H (673–973 which are conditions typically employed activation of these for metathesis reaction. A new assignment Mo 3d binding energies to oxidation states was applied analysis reduced samples. During Ar, part hexavalent present initial samples underwent Mo(V), could also be detected EPR. The alumina-supported Mo(VI) found produce surfaces, on Mo(VI), Mo(IV), Mo(II), and, at temperatures above 900 K, Mo(O), coexist. For about 800 distributions states, differ from those reported literature a Mo(V) contribution not exceeding 10% total presence derived. When subsequently treated inert gas 973 K partial reoxidation surface observed.