Effect of pH in the preparation of γ-Bi2MoO6 for oxidative dehydrogenation of n-butene to 1,3-butadiene: Correlation between catalytic performance and oxygen mobility of γ-Bi2MoO6

γ-Bi2MoO6 catalysts were prepared by a co-precipitation method with a variation of pH value (pH 1–7), and they were applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene in a continuous flow fixed-bed reactor. Temperature-programmed reoxidation (TPRO) measurements were carried out to determine the oxygen mobility to make up lattice oxygen of γ-Bi2MoO6 consumed in the reaction. It was observed that the catalytic performance of γ-Bi2MoO6 was closely related to the oxygen mobility of γ-Bi2MoO6. The yield for 1,3-butadiene was monotonically increased with decreasing TPRO peak temperature and with increasing TPRO peak area. Among the catalysts tested, the γ-Bi2MoO6 catalyst prepared at pH 3 showed the best catalytic performance due to its facile oxygen mobility.