A single-step reaction of nitrobenzene into para-aminophenol was carried out in the gas phase using metal-supported zeolite as a bifunctional catalyst. A significant amount of para-aminophenol was produced with aniline and ortho-aminophenol without using any environmentally undesirable liquid acid. For the selective formation of para-aminophenol, Pt supported on H-ZSM-5 was the best combination of metal and acid catalysts. The selectivity to para-aminophenol depended greatly on the Al concentration of H-ZSM-5; that is, HZSM-5 with intermediate Al concentration gave the highest selectivity. Pt particles on H-ZSM-5 were characterized by the measurements of adsorbed CO, TEM and IR spectra. (C) 2004 Elsevier B.V. All rights reserved.