Power generation systems based on fuel cell technology are an interesting option for mobile auxiliary power units (APU). Hydrogen for the fuel cell can be supplied from conventional fuels, such as diesel fuel. Mobile APUs must possess high efficiencies in order to be compact, lightweight, and capable of supply hydrogen on dynamic demand. Microstructured reactors have increased mass and heat transport rates as well as space time yields compared to conventional reactors. Therefore, they potentially meet the requirements of these mobile systems. The presented work examines and evaluates the application of microstructured devices for the steam reforming of diesel fuel by applying a Rh/CeO2 catalyst system. A microstructured reactor was designed where the heat for the endothermic steam reforming reaction was supplied in adjacent microchannels via catalytic combustion of hydrogen, which is potentially substituted in a complete APU system by use of the anode off gases of the fuel cell which contains less hydrogen and is of different composition. Dynamic experiments performed with this prototype reactor revealed a very fast response of the reaction on transients in reactant feed. A constant reformate flow was reached within 35 s. Reformate usually contained 70 vol% of hydrogen in the dry product gas. (c) 2012 Published by Elsevier B.V.