Preparation and Characterization of Bismuth Molybdate Catalyst for Oxidative Dehydrogenation of n-Butene into 1,3-Butadiene

摘要

α-Bi_2Mo_3O_(12) and γ-Bi_2MoO_6 catalysts were prepared by co-precipitation method, and they were applied to the oxidative dehydrogenation of n-butene into 1,3-butadiene in a continuous flow fixed-bed reactor. Formation of α-Bi_2Mo_3O_(12) and γ-Bi_2MoO_6 catalysts was well confirmed by XRD, Raman spectroscopy, and ICP-AES analyses. The γ-Bi_2MoO_6 catalyst exhibited a better catalytic performance than the α-Bi_2Mo_3O_(12) catalyst. Catalytic performance of γ-Bi_2MoO_6 strongly depended on the pH value used in the co-precipitation step. It was also revealed that a mixed catalyst comprising γ-Bi_2MoO_6 (90 wt%) and small amount of α-Bi_2Mo_3O_(12) (10 wt%) showed the best catalytic performance due to the synergy effect of two components. It is believed that the high catalytic performance of the mixed catalyst resulted from high diffusion coefficient of lattice oxygen in the γ-Bi_2MoO_6 and from abundant chemisorption sites for n-butene in the α-Bi_2Mo_3O_(12).