A new activation process was proposed for supported nickel catalysts in CO2 reforming of methane. The activation was performed by heating the catalyst up to 800degreesC under a mixture of CH4/O-2 = 2. Before activation the nickel catalysts present only nickel aluminate species; these species are partially reduced to metallic nickel during activation. SEM pictures showed formation of carbon filaments embedded with dispersed nickel particles, which are the active sites for methane reforming with CO2. The nickel loading and the support greatly influence the catalyst stability, the conversion increased with Ni loading on alumina support, while the promotion with zirconia did not improve the catalytic behavior. (C) 2004 Elsevier B.V. All rights reserved.