Effect of ZrO2 Crystalline Phase on the Performance of Ni-B/ZrO2 Catalyst for the CO Selective Methanation

Amorphous Ni-B/ZrO2 catalysts were prepared by coprecipitation-chemical reduction with KBH4 aqueous solution, and various crystalline phase ZrO2 (amorphous-ZrO2, tetragonal-ZrO2 and monoclinic-ZrO2) supported Ni-B catalysts were obtained by thermal treatment in 5%H-2-N-2 stream at different temperature. The effect of ZrO2 polymorphs and the treatment temperature on the catalytic performance for the CO selective methanation were investigated, and the catalysts were characterized by N-2 physisorption, Powder X-ray diffraction (XRD), Temperature-Programmed Desorption (CO-TPD and H-2-TPD), and Differential Scanning Calorimeter (DSC). The treatment temperature affected strongly the crystalline structure of ZrO2, and the CO methanation activity and selectivity of the Ni-B/ZrO2 catalysts were significantly influenced by the crystalline phase of ZrO2. Of the three forms of ZrO2 polymorphs (amorphou-ZrO2, tetragonal-ZrO2 and monoclinic-ZrO2), the amorphous-ZrO2 supported nickle catalyst showed highest CO methanation activity, attributing in large part to the largest specific surface area and the optimum CO/H-2 absorption intensity of the Ni-B/amorphous-ZrO2 catalyst.