Synthesis of Ln-doped MCM-41 mesoporous materials and their catalytic performance in oxidation of styrene
来源期刊：JOURNAL OF RARE EARTHS2008年第1期
论文作者：GUO Yanglong ZHAN Wangcheng LU Guanzhong WANG Yunsong GUO Yun
Key words：Ln-MCM-41; mesoporous materials; styrene; oxidation; rare earths;
Abstract: Using cetyl-trimethyi-ammonium bromide (CTMAB) as the template agent and tewaethylorthosilicate (TEOS) as the silica source, the MCM-41 mesoporous materials were synthesized with La or Ce incorporated in the framework under hydrothennal conditions. The structure and the state of La or Ce were investigated through the analyses of XRD, nitrogen adsorption-desorption, FT-IR, and UV-Vis. XRD and N2 adsorption-desorption results showed that Ln-MCM-41 exhibited the loss of the lattice ordering of the MCM-41 construct, and larger unit cell parameter and pore diameter than pure silica MCM-41. The FT-IR and UV-Vis results indicated the presence of isolated tetra-coordinated La or Ce ions in the framework and other Ln species dispersed highly on the Ln-MCM-41 surface simultaneously. Furthermore, their catalytic behaviors in the oxidation of styrene were studied using H2O2 as the oxidant. The La-MCM-41 catalysts exhibited high reactivity and the reactivity increased with the increase of the La content in the La-MCM-41 samples. On the contrary, Ce-MCM-41 catalysts showed low reactivity in the oxidation of styrene and the conversion of styrene decreased with the increase of the Ce content in the Ce-MCM-41 samples.
GUO Yanglong1，ZHAN Wangcheng1，LU Guanzhong1，WANG Yunsong1，GUO Yun1
(1.Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237. China)
Abstract:Using cetyl-trimethyi-ammonium bromide (CTMAB) as the template agent and tewaethylorthosilicate (TEOS) as the silica source, the MCM-41 mesoporous materials were synthesized with La or Ce incorporated in the framework under hydrothennal conditions. The structure and the state of La or Ce were investigated through the analyses of XRD, nitrogen adsorption-desorption, FT-IR, and UV-Vis. XRD and N2 adsorption-desorption results showed that Ln-MCM-41 exhibited the loss of the lattice ordering of the MCM-41 construct, and larger unit cell parameter and pore diameter than pure silica MCM-41. The FT-IR and UV-Vis results indicated the presence of isolated tetra-coordinated La or Ce ions in the framework and other Ln species dispersed highly on the Ln-MCM-41 surface simultaneously. Furthermore, their catalytic behaviors in the oxidation of styrene were studied using H2O2 as the oxidant. The La-MCM-41 catalysts exhibited high reactivity and the reactivity increased with the increase of the La content in the La-MCM-41 samples. On the contrary, Ce-MCM-41 catalysts showed low reactivity in the oxidation of styrene and the conversion of styrene decreased with the increase of the Ce content in the Ce-MCM-41 samples.
Key words:Ln-MCM-41; mesoporous materials; styrene; oxidation; rare earths;
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