Influence of pore size of SBA-15 on activity and selectivity of H3[PMo12O40] supported on tailored SBA-15
Influence of pore size of SBA-15 on activity and selectivity of H3[PMo12O40] supported on tailored SBA-15
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DOI：
10.1016/j.micromeso.2015.04.022
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发表时间：
2015-09
影响因子：
5.2
通讯作者：
R. Zubrzycki;T. Ressler
中科院分区：
文献类型：
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作者：
R. Zubrzycki;T. Ressler
合成了大孔SBA-15，并将其用作钼基氧化催化剂的载体材料。H3[PMo 12 O 40]负载在SBA-15上，具有改性的孔径（10，14，19 nm）。所有样品均以1个Keggin离子/13 nm 2的相似表面覆盖率制备，与孔半径无关。采用原位X射线吸收光谱法研究了不同孔径（10、14、19 nm）的SBA-15负载H3[PMo 12 O 40]（PMo 12-SBA-15）在丙烯选择氧化反应条件下的结构演变和催化活性。PMo 12-SBA-15（10，14，19 nm）在丙烯氧化条件下热处理期间形成主要为四面体[MoO 4]和八面体[MoO 6]单元的混合物。检测到较高浓度的八面体[MoO 6]单元和较高浓度的低聚[MoxOy]单元。PMo 12-SBA-15（10 nm）与act. PMo12-SBA-15（14，19 nm）。[MoxOy]单位的浓度越高，与具有较低浓度的[MoxOy]单元的活化PMo 12-SBA-15（14，19 nm）相比，PMo 12-SBA-15（10 nm）导致增加的催化活性。在丙烯氧化过程中对氧化产物的选择性是相当的，并且在很大程度上独立于孔半径的行为。PMo12-SBA-15（10、14、19 nm）。显然，定制二氧化硅SBA-15的孔半径允许制备Mo氧化物模型系统，以研究在类似的表面覆盖率下特征氧化物物种的活性和结构之间的相关性。
Large pore SBA-15 was successfully synthesized and used as support material for molybdenum based oxidation catalysts. H3[PMo12O40] was supported on SBA-15 with modified pore radii (10, 14, 19 nm). All samples were prepared with a similar surface coverage of 1 Keggin ion per 13 nm2independent of the pore radii. Structural evolution and catalytic activity of H3[PMo12O40] supported on SBA-15 (PMo12-SBA-15) with different pore radii (10, 14, 19 nm) were investigated under selective propene oxidation conditions byin situX-ray absorption spectroscopy investigations. PMo12-SBA-15 (10, 14, 19 nm) formed a mixture of mostly tetrahedral [MoO4] and octahedral [MoO6] units during thermal treatment in propene oxidation conditions. A higher concentration of octahedral [MoO6] units and higher oligomerized [MoxOy] units were detected for act. PMo12-SBA-15 (10 nm) compared to act. PMo12-SBA-15 (14, 19 nm). The higher concentration of [MoxOy] units present in act. PMo12-SBA-15 (10 nm) resulted in an increased catalytic activity compared to activated PMo12-SBA-15 (14, 19 nm) with a lower concentration of [MoxOy] units. Selectivities towards oxidation products during propene oxidation were comparable and largely independent of the pore radii of act. PMo12-SBA-15 (10, 14, 19 nm). Apparently, tailoring the pore radius of silica SBA-15 permitted to prepare Mo oxide model systems to investigate correlation between activity and structure of characteristic oxide species at similar surface coverage.