Stabilization of Cu/ZnO Based Catalysts by Nickel Additive in Methanol Decomposition

A series of Cu/Zn based catalysts with and without Ni, prepared by the co-precipitation method, has been studied for methanol decomposition. CO and H2 are the major products. The Cu/Zn catalysts show a low initial activity and a poor stability. The formation of the CuZn alloys was observed in the deactivated Cu/Zn catalysts which were used for methanol decomposition at 250 ℃. When small amounts of Ni were added in the catalyst, the Cu/Zn/Ni(molar ratio 5/4/x) catalysts showed a high activity at a low temperature. The activity and the stability of the catalyst depend on the nickel content. The activity of the Cu/Zn/Ni catalysts was maintained at a relatively stable value of 78% conversion of methanol with 95% selectivity of H2, 93%selectivity of CO, and a more than 70% yield of hydrogen was obtained at 250 ℃ when x≥1.The stability of the Cu/Zn/Ni(molar ratio 5/4/x) catalysts showed the maximum(ca 88%)when x＝1. The stabilization effect of nickel on the Cu/Zn based catalysts may lead to the increasing of the dispersion of active Cu species and the prevention of CuZn alloys formation.