The invention relates to a method for operating a dehydrogenation reactor for the dehydrogenation of hydrocarbons is provided wherein the dehydrogenation reactor comprises a potassium promoted iron oxide catalyst, the hydrocarbons being dehydrogenated in contact with the catalyst and carbon dioxide is introduced during a) start-up of the reactor, b) shut-down of the reactor, and c) steaming procedures, wherein the carbon dioxide is introduced in conjunction with steam in at least one method step.