Photocatalysed selective oxidation of cyclohexane to benzene on MoOx/TiO2

Heterogeneous oxidative dehydrogenation of cyclohexane to benzene was found to occur under photocatalytic conditions on MoOx/TiO2. Initial cyclohexane conversion of 15% and maximum selectivity to benzene of 65% were achieved at 308 K on 8 wt.% MoOx/TiO2 under irradiation with a continuous flow reactor. The main by-product was carbon dioxide. Catalyst deactivation was observed. Titania exhibited high activity of total oxidation to carbon dioxide but was not selective for conversion to benzene. Polymolybdate species seem to be responsible for changing the selectivity of titania, favouring the formation of benzene. Nevertheless, when supported on α- or γ-alumina they promote only the formation of carbon dioxide.