Dehydrogenatable hydrocarbons may be subjected to a dehydrogenation reaction in which the hydrocarbons are treated with a dehydrogenation catalyst comprising a modified iron compound in the presence of steam in a multicatalyst bed system. The reaction mixture containing unconverted hydrocarbons, dehydrogenated hydrocarbons, hydrogen and steam is then contacted with an oxidation catalyst whereby hydrogen is selectively oxidized in preference to carbon dioxide and carbon monoxide or hydrocarbons. The selective oxidation of hydrogen will improve the combustion thereof and supply the necessary heat which is required for a subsequent dehydrogenation treatment. The selective oxidation catalyst which is used will comprise a noble metal of Group VIII of the Periodic Table and, if so desired, a metal of Group IA or IIA of the Periodic Table composited on a porous inorganic support. The inorganic support will have been calcined prior to impregnation thereof at a temperature in the range of from about 900.degree. to about 1500.degree. C. in the absense or presence of steam to provide a catalyst which possesses increased stability and activity when compared to prior catalysts.