Three rhodium catalysts supported on rare earth oxides with redox properties, Rh/CeO 2 , Rh/Pr 6 O 11 , and Rh/Tb 4 O 7 , were tested for their ability to trigger oxidative reforming of n-butane at room temperature. Only Rh/CeO 2 triggered the oxidative reforming, owing to the heat generated by the spontaneous oxidation of the CeO 2− x species produced by prior reduction of the supported catalyst with H 2 . Although the three rare earth oxides were reduced to CeO 1.91 , Pr 2 O 3 , and Tb 2 O 3 , respectively, by H 2 at ⩾873K, CeO 1.91 was the only reduced oxide that was oxidized upon exposure to O 2 at room temperature. These results indicate that the ability of the reduced oxide support to undergo oxidation at room temperature was crucial for triggering oxidative reforming of n-butane at room temperature.