Catalytic properties of plate-type copper-based catalysts, for steam reforming of methanol, on an aluminum plate prepared by electroless plating

Abstract

Steam reforming of methanol is attracting interest as a reaction that generates hydrogen for fuel cells. As it involves a relatively large endothermic reaction and would be applied as an on-board reaction, the reformer requires effective exchange of heat energy, quick load response and downsized dimensions. The wall-type reactor is one of the reactors that can meet these demands. In order to develop a plate-type reforming catalyst for the wall-type methanol reformer, we prepared plate-type copper-based catalysts on an aluminum substrate by electroless plating and examined their reforming properties. Results showed that the prepared catalysts had different reforming properties depending on the metal species used in the intermediate plating. A plate-type Cu·Fe/Zn catalyst on an intermediate iron plating exhibited high reforming properties. The activity of this catalyst was improved by oxidation before the reaction. The activity of the oxidized Cu·Fe/Zn catalyst was nearly equal to that of the commercial granular reforming catalyst in low temperature regions and was higher than the activity of this type in high regions. According to measurements of physicochemical properties for the Cu·Fe/Zn catalyst, the zinc incorporated in the plated layer moved from the bulk to the surface by oxidation, and active sites for methanol reforming were formed because of the presence of zinc in proximity to copper. Such movement of zinc was thought to be a factor for improvement in reforming of the Cu·Fe/Zn catalyst. Even after the activity of the oxidized Cu·Fe/Zn catalyst had declined, it could be restored to its initial activity by reoxidation. Such activity restoration by reoxidation could be repeated.