Hamdy Mohamed S, Berg Otto, Jansen Jacobus C, Maschmeyer Thomas, Moulijn Jacob A, Mul Guido
Reactor and Catalysis Engineering, DelftChemTech, Technische Universiteit Delft, Julianalaan 136, 2628 BL, Delft, The Netherlands.
Chemistry. 2005 Dec 23;12(2):620-8. doi: 10.1002/chem.200500649.
A series of TiO2-TUD-1 samples was synthesized with a variable Ti loading in the range Si/Ti = 100, 20, 2.5, and 1.6, by using a one-pot surfactant-free procedure. The materials obtained were characterized by elemental analysis; X-ray diffraction (XRD); N2 sorption measurements; high-resolution TEM (HR-TEM); 29Si NMR, UV-visible and Raman spectroscopy. As a function of increasing metal loading either isolated Ti atoms, or (above a Ti loading of approximately 2.5 wt- %) combinations of isolated Ti atoms and anatase (TiO2) nanoparticles were obtained; both were incorporated in the highly porous siliceous matrix. The photocatalytic performance of these materials was tested by studying the propane oxidation process following irradiation at lambda = 365 nm, selectively activating the anatase nanoparticles. In comparison to commercial anatase powder, TiO2 nanoparticles in TUD-1 showed high photochemical selectivity towards acetone, the sample with a Si/Ti ratio of 1.6 being the most selective. Size and confinement effects are consistent with the difference in performance of the TUD-1 materials and TiO2, limiting the number of electron transfers available for each propane molecule.
通过一锅无表面活性剂法合成了一系列Ti负载量可变的TiO₂-TUD-1样品，其Si/Ti比范围为100、20、2.5和1.6。对所得材料进行了元素分析、X射线衍射（XRD）、N₂吸附测量、高分辨率透射电子显微镜（HR-TEM）、²⁹Si核磁共振、紫外可见光谱和拉曼光谱表征。随着金属负载量的增加，得到了孤立的Ti原子，或者（在Ti负载量约为2.5 wt-%以上）孤立的Ti原子和锐钛矿（TiO₂）纳米颗粒的组合；两者都掺入了高度多孔的硅质基质中。通过研究在λ = 365 nm照射下的丙烷氧化过程来测试这些材料的光催化性能，选择性地激活锐钛矿纳米颗粒。与商业锐钛矿粉末相比，TUD-1中的TiO₂纳米颗粒对丙酮表现出高光化学选择性，Si/Ti比为1.6的样品选择性最高。尺寸和限域效应与TUD-1材料和TiO₂的性能差异一致，限制了每个丙烷分子可用的电子转移数。
