Two bimetallic PtNi catalysts supported on a nanostructured gamma-Al2O3 together with the corresponding monometallic materials, employed for the dry reforming of methane, have been prepared and characterized. Characterization of the catalysts, in reduced form, has been performed by FTIR spectroscopy of adsorbed carbon monoxide at low and room temperature. XRD, TEM and XPS analysis have also been performed. IR spectra of adsorbed CO indicate that the surface of the PtNi catalysts is dominated by Pt centers, whose electron-withdrawing character is increased by Ni. It has also been confirmed the formation of PtNi alloy, which is enriched at the surface by Pt and has smaller metal crystal size than metal particles in monometallic Pt and Ni catalysts. The alloy formation is associated with higher activity and lower production of carbonaceous materials upon dry reforming of methane. (C) 2010 Elsevier Inc. All rights reserved.