By using pulse surface reaction rate analysis (PSRA), the detailed structure of the intermediate hydrocarbon species was revealed by measuring the dynamic behavior of both CO and H-2 produced from the CO2-CH4 reaction on supported Ni catalysts. It was found that the number of hydrogen atoms involved in the intermediate was different from one catalyst support to another : 2.7 for MgO, 2.5 for ZnO, 2.4 for Al2O3, 1.9 for TiO2, and 1.0 for SiO2.