Investigation on oxidative steam reforming of methanol over CuZnAlZr catalyst I. Optimization of catalyst formulation

Low-temperature steam reforming of methanol is a relevant technique for on-board supply of hydrogen for fuel-cell vehicles. Recently, much attention was paid on oxidative steam reforming of methanol due to its quick response and auto-thermal properties. This paper deals with the optimization of catalyst formulation of CuZmAlZr composite oxide system. The catalyst was prepared by co-precipitation from aqueous solutions of Cu, Zn, Al and Zr nitrates and Na2CO3 (pH = 7.6) at 65 degreesC. The influence of the catalyst composition, such as the ratios of n (CuZn)/n (AlZr), n (Cu)/n (Zn) and n (Al)/n (Zr), on its catalytic performance for oxidative steam reforming of methanol to hydrogen was investigated. The optimized composition of the catalyst was (Cu7Zn3)(7)(Al6Zr4)(3). Over this catalyst, the methanol conversion reached 91% at 200 degreesC, while the phi(CO) was only as low as 0.08%. The dispersion of CuO species and its occupation on the catalyst surface are the determining factors for the catalyst activity. The component Zn is responsible for the dispersion of CuO, while the components Al and Zr give assistance to stabilize the existence of Cu species on the catalyst surface.