CIESC Journal ›› 2020, Vol. 71 ›› Issue (11): 4999-5006.DOI: 10.11949/0438-1157.20200778

• Celebration Column for School of Chemistry and Chemical Engineering, Nanjing University • Previous Articles     Next Articles

Preparation of catalyst Pd-Au/1cTiO2/SiO2 and epoxidation of olefins

Wei ZENG(),Jia LIU,Dejin ZHANG,Guoqiang YANG(),Zhibing ZHANG   

  1. School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
  • Received:2020-06-20 Revised:2020-07-13 Online:2020-11-05 Published:2020-11-05
  • Contact: Guoqiang YANG

Pd-Au/1cTiO2/SiO2催化剂的制备及其烯烃的环氧化性能

曾伟(),刘甲,张德谨,杨国强(),张志炳   

  1. 南京大学化学化工学院,江苏 南京 210023
  • 通讯作者: 杨国强
  • 作者简介:曾伟(1995—),男,硕士研究生,MF1824002@smail.nju.edu.cn
  • 基金资助:
    国家自然科学基金项目(21776122);国家重点研发计划项目(2018YFB0604605)

Abstract:

Two kinds of Pd-Au bimetallic nanocatalysts (0.01% Pd-Au/1cTiO2/SiO2 and 0.05% Pd-Au/1cTiO2/SiO2) were prepared by using 1cTiO2/SiO2 as support, which had a single layer TiO2 thin film on SiO2 substrate by atomic layer deposition (ALD) technique. Deposition of Au and Pd on 1cTiO2/SiO2 was carried out by means of deposition precipitation and impregnation. Au loading of the two catalysts was both 0.01%(mass), and the Pd loading were 0.01% and 0.05% respectively. The prepared catalysts were characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS), and the morphology of nanoparticles, the chemical valence state and composition of Pd and Au elements were determined. The Pd-Au bimetallic nanocatalysts were used in the selective epoxidation of cyclohexene using oxygen as oxidant, and the conditions such as the reaction solvent, the type of co-reductant and the reaction temperature were screened. The applicability of the catalyst to different structural olefins was investigated under the optimized reaction conditions. For cyclic olefins, the substrate conversion rate is greater than 95%, and the epoxy product selectivity is greater than 91%. After the catalyst is recycled 5 times, the catalytic activity and reaction selectivity remain unchanged.

Key words: catalyst, nanomaterials, epoxidation, olefin, reactivity, stability

摘要:

使用沉淀沉积法及溶液浸渍法分别将Au和Pd纳米粒子负载在原子层沉积法制备的1cTiO2/SiO2载体上,制备出两种不同Pd负载量的Pd-Au双金属活性中心纳米催化剂。采用TEM、EDX、XPS对所制备的催化剂进行了详细的表征,确定了纳米粒子的形貌、Pd-Au元素的化学价态和组成。测试了该类催化剂在以氧气为氧源的环己烯环氧化反应中的活性和选择性,并对反应溶剂、共还原剂种类、反应温度等条件进行了筛选。在优化后的反应条件下考察了该催化剂对不同结构烯烃的适用性。对于环状烯烃,底物转化率均大于95%,环氧产物选择性均大于91%。催化剂在循环回收5次后,催化活性和反应选择性保持不变。

关键词: 催化剂, 纳米材料, 环氧化, 烯烃, 活性, 稳定性

CLC Number: