Rod-like, hexagonal and fiber-like SBA-15 mesoporous silicas were synthesized to support MnO_x for toluene oxidation. This study showed that the morphology of the supports greatly influenced the catalytic activity in ...Rod-like, hexagonal and fiber-like SBA-15 mesoporous silicas were synthesized to support MnO_x for toluene oxidation. This study showed that the morphology of the supports greatly influenced the catalytic activity in toluene oxidation. MnO_x supported on rod-like SBA-15(R-SBA-15) displayed the best catalytic activity and the conversion at 230°C reached more than 90%, which was higher than the other two catalysts. MnO_x species consisted of coexisting MnO_2 and Mn_2O_3 on the three kinds of SBA-15 samples. Large amounts of Mn_2O_3 species were formed on the surface and high oxygen mobility was obtained on MnO_x supported on R-SBA-15, according to the H_2 temperature programmed reduction(H_2-TPR)and X-ray photoelectron spectroscopy(XPS) results. The Mn/R-SBA-15 catalyst with greater amounts of Mn_2O_3 species possessed a large amount of surface lattice oxygen, which accelerated the catalytic reaction rate. Therefore, the surface lattice oxygen and high oxygen mobility were critical factors on the catalytic activity of the Mn/R-SBA-15 catalyst.展开更多
Jacobsen’s catalyst was immobilized onto SBA-15 by multi-step grafting, and this new heterogenized catalyst exhibited comparable catalytic performance with the corresponding homogeneous counterpart for the epoxidatio...Jacobsen’s catalyst was immobilized onto SBA-15 by multi-step grafting, and this new heterogenized catalyst exhibited comparable catalytic performance with the corresponding homogeneous counterpart for the epoxidation of alkenes.When NH4OAc were used as cocatalyst both yields and ee’s were higher than that of without co catalyst.展开更多
基金supported by the National Nature Science Foundation of China (Nos.21377016 and 21577014)Programme of Introducing Talents of Discipline to Universities (No.B13012)Program for Changjiang Scholars and Innovative Research Team in University (No.IRT_13R05)
文摘Rod-like, hexagonal and fiber-like SBA-15 mesoporous silicas were synthesized to support MnO_x for toluene oxidation. This study showed that the morphology of the supports greatly influenced the catalytic activity in toluene oxidation. MnO_x supported on rod-like SBA-15(R-SBA-15) displayed the best catalytic activity and the conversion at 230°C reached more than 90%, which was higher than the other two catalysts. MnO_x species consisted of coexisting MnO_2 and Mn_2O_3 on the three kinds of SBA-15 samples. Large amounts of Mn_2O_3 species were formed on the surface and high oxygen mobility was obtained on MnO_x supported on R-SBA-15, according to the H_2 temperature programmed reduction(H_2-TPR)and X-ray photoelectron spectroscopy(XPS) results. The Mn/R-SBA-15 catalyst with greater amounts of Mn_2O_3 species possessed a large amount of surface lattice oxygen, which accelerated the catalytic reaction rate. Therefore, the surface lattice oxygen and high oxygen mobility were critical factors on the catalytic activity of the Mn/R-SBA-15 catalyst.
文摘Jacobsen’s catalyst was immobilized onto SBA-15 by multi-step grafting, and this new heterogenized catalyst exhibited comparable catalytic performance with the corresponding homogeneous counterpart for the epoxidation of alkenes.When NH4OAc were used as cocatalyst both yields and ee’s were higher than that of without co catalyst.
