A bi-metallic 2wt.% Pt25Ir75/boehmite catalyst has been synthesized from a microemulsion system and characterized in detail with techniques including TPR, XPS, SEM and TEM-EDX. Additional reduction treatment changes the structural phase of the support as well as the character of the metal particles. TEM-EDX revealed unexpectedly large agglomerates with platinum clusters lying on top of iridium plate-like clusters. The catalytic activity with respect to ring opening of indan was Studied at 325 degreesC and atmospheric pressure and compared with the catalytic performance of corresponding monometallic Pt and Ir/boehmite catalysts. The bi-metallic 2wt.% Pt(25)lr(75)/boehmite catalyst was also tested in a more realistic environment for industrial applications, i.e. at high pressure (40 bar). In essence, the obtained catalytic results indicated superior catalytic activity for the Ir and Pt-Ir catalysts. Concerning selectivity the product distribution varied widely, with hydrogenation and selective ring opening being the most prominent reactions for high pressure and atmospheric pressure conditions, respectively. At atmospheric pressure, all catalysts were slightly deactivated whereas at high pressure, the Pt-Ir catalyst showed a high operating stability with no deactivation. (C) 2003 Elsevier B.V. All rights reserved.