MnO2 nanorod supported gold nanoparticles with enhanced activity for solvent-free aerobic alcohol oxidation
MnO2 nanorod supported gold nanoparticles with enhanced activity for solvent-free aerobic alcohol oxidation
复制标题
MnO2 纳米棒负载的金纳米颗粒具有增强的无溶剂需氧酒精氧化活性
DOI：
10.1021/jp711333t
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发表时间：
2008-05-01
影响因子：
3.7
通讯作者：
Fan, Kang-Nian
中科院分区：
文献类型：
--
作者：
Wang, Lu-Cun;Liu, Yong-Mei;Fan, Kang-Nian
以尿素为沉淀剂，采用均匀沉积-沉淀法制备了纳米棒和常规颗粒两种不同形态的mno2负载金纳米颗粒。采用N-2吸附、x射线衍射（XRD）、透射电子显微镜（TEM）、氢程序升温还原（H-2-TPR）和x射线光电子能谱（XPS）等技术对催化剂进行了广泛的表征，考察了催化剂在无溶剂条件下液相好氧氧化苯甲醇的性能。TEM分析表明，两种类型的金催化剂具有相似的金粒度分布。TPR结果表明，Au的存在强烈地促进了Au/MnO2- r体系中MnO2的还原。在反应前后，XPS显示了MnO2纳米棒载体上的还原态和氧化态Au。纳米二氧化锰纳米棒负载的金催化剂的催化活性比在工业二氧化锰粉末上的催化活性显著增强。Au/MnO2- r催化剂的催化活性增强是由于Au与MnO2纳米棒反应表面之间的强相互作用导致了大量的氧化金和表面氧空位的存在。
Gold nanoparticles supported on beta-MnO2 with different morphologies, i.e., nanorods and conventional particulates, were prepared by homogeneous deposition-precipitation using urea as the precipitation agent. The catalysts were extensively characterized by a combination of different techniques (N-2 adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H-2-TPR), and X-ray photoelectron spectroscopy (XPS)) in relation to their performance for liquid-phase aerobic oxidation of benzyl alcohol under solvent-free conditions. TEM analysis showed that the two types of gold catalysts have similar gold particle size distributions. TPR results indicated that the presence of Au strongly promotes MnO2 reduction in the Au/MnO2-R system. XPS revealed both reduced and oxidized Au species on the MnO2 nanorods support before and after the reaction. Significantly enhanced catalytic activity was observed for gold catalyst supported on MnO2 nanorods, as compared with that on commercial MnO2 powders. The enhanced catalytic activity of the Au/MnO2-R catalyst was attributed to the beneficial presence of higher amount of oxidized gold species and surface oxygen vacancies resulting from the strong interaction between Au and the well-defined reactive surface of MnO2 nanorods.