Effect of ZrO 2 Crystalline Phase on the Performance of Ni-B/ZrO 2 Catalyst for the CO Selective Methanation

Abstract

Amorphous Ni-B/ZrO 2 catalysts were prepared by coprecipitation-chemical reduction with KBH 4 aqueous solution, and various crystalline phase ZrO 2 (amorphous-ZrO 2, tetragonal-ZrO 2 and monoclinic-ZrO 2) supported Ni-B catalysts were obtained by thermal treatment in 5%H 2-N 2 stream at different temperature. The effect of ZrO 2 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 ZrO 2, and the CO methanation activity and selectivity of the Ni-B/ZrO 2 catalysts were significantly influenced by the crystalline phase of ZrO 2. Of the three forms of ZrO 2 polymorphs (amorphou-ZrO 2, tetragonal-ZrO 2 and monoclinic-ZrO 2), the amorphous-ZrO 2 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-ZrO 2 catalyst.