The gas-phase catalytic oxidation of benzene over Cu-supported ZSM-5 catalysts was studied using molecular oxygen as an oxidant. Main products were carbon oxides (CO2 + CO) and phenol. Phenol was formed only when using ZSM-5 type zeolite as a support. Cu ion-exchanged HZSM-5 (Cu-HZSM-5) zeolite had higher catalytic activity for phenol formation than the NaZSM-5 counterpart (Cu-NaZSM-5). A Cu-HZSM-5 zeolite with larger Si/Al atomic ratio was found to inhibit the formation of carbon dioxides and increase the selectivity of phenol formation. The deactivation of the Cu-HZAM-5 zeolite was recovered by calcination at 773 K in air flow. Cu+ species on the zeolite were suggested to play an important role for phenol formation. (C) 2002 Elsevier Science B.V. All rights reserved.