Ru/NiAl-LDH-o-CNTs乳液催化剂的制备及其苯甲醇选择氧化性能

Fabrication of a Ru-NiAl layered double hydroxide-oxidized CNT hybrid catalyst for the selective oxidation of benzyl alcohol to benzaldehyde

  • 摘要: 采用温和水热方法制备了由功能化碳纳米管(o-CNTs)和片状水滑石(NiAl-LDHs)组成的NiAl-LDH-o-CNTs复合材料。采用X射线衍射(XRD)和透射电子显微镜(TEM)技术手段研究了NiAl-LDH-o-CNTs复合物的结构特征和形貌,通过光学显微镜技术手段考察了NiAl-LDHs、o-CNTs和NiAl-LDH-o-CNTs复合物形成的乳液体系特征。以苯甲醇选择氧化制备苯甲醛为探针反应,研究了NiAl-LDHs、o-CNTs和NiAl-LDH-o-CNTs材料的乳化能力与Ru基催化剂催化性能之间的内在规律关系。结果表明,NiAl-LDH-o-CNTs固体乳化剂的乳化能力优于o-CNTs和NiAl-LDHs。以NiAl-LDH-o-CNTs为载体,Ru为活性组份的Ru/NiAl-LDH-o-CNTs催化剂催化活性最高,对苯甲醇的转化率高达96%,选择性高于99.9%。

     

    Abstract: A NiAl layered double hydroxide-oxidized CNT (NiAl-LDH-o-CNT) hybrid was synthesized by a mild hydrothermal method using o-CNTs, Al(NO3)3·9H2O and Ni(NO3)2·6H2O as the precursors. It was impregnated with RuCl3 as a catalyst for the oxidation of benzyl alcohol to benzaldehyde and its activity compared with NiAl-LDHs and o-CNTs. The crystal structure and morphological characteristics of the NiAl-LDH-o-CNTs hybrid were characterized by XRD and TEM. The characteristics of emulsions of NiAl-LDHs, o-CNTs and the hybrid in a water-toluene system were investigated by optical microscopy. It was found that among these supports, the hybrid was best emulsified with the narrowest and smallest droplet size distribution (ca. 90 μm) and the largest fraction (95%) of droplet volume. The activity and selectivity for benzyl alcohol oxidation to benzaldehyde increased with interface area for all the emulsions. The Ru/NiAl-LDH-o-CNTs hybrid had the best catalytic performance with the highest values of conversion and selectivity of 96% and 99.9%, respectively.

     

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