化工进展 ›› 2020, Vol. 39 ›› Issue (5): 1756-1764.DOI: 10.16085/j.issn.1000-6613.2019-1204

• 工业催化 • 上一篇    下一篇

埃洛石负载的纳米金可控制备及对环己烷选择性氧化的催化性能

张学云(), 祝琳华(), 司甜   

  1. 昆明理工大学化学工程学院,云南 昆明 650500
  • 出版日期:2020-05-05 发布日期:2020-05-25
  • 通讯作者: 祝琳华
  • 作者简介:张学云(1988—),男,硕士研究生,研究方向为化工催化材料。E-mail:1039787896@qq.com
  • 基金资助:
    国家自然科学基金(21166010)

Controllable preparation of halloysite supported gold nanoparticles and their catalytic performance for cyclohexane oxidation

Xueyun ZHANG(), Linhua ZHU(), Tian SI   

  1. Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan,China
  • Online:2020-05-05 Published:2020-05-25
  • Contact: Linhua ZHU

摘要:

埃洛石纳米管(HNTs)是一类具有独特物理结构和化学性质的天然黏土化合物,本文以经过提纯和聚二烯丙基二甲基氯化铵溶液(PDDA)改性的埃洛石为载体,将预先制备的粒径可控的金溶胶负载到改性埃洛石(PHNTs)表面得到负载型的纳米金颗粒,通过调节氯金酸前体的浓度和用量,实现了对负载型纳米金尺寸的有效调控,透射电镜表征结果显示,埃洛石负载的纳米金分散性良好,平均粒径分别处于2nm以下、2~5nm和5nm以上。以环己烷的液相选择性氧化为模型反应,评价了所制备的不同尺度负载型纳米金粒子的活性和对环己醇和环己酮的选择性。结果表明:纳米金颗粒的平均粒径处于2~5nm时,表现出最好的催化活性和选择性,在170℃和2.0MPa下反应2h,环己烷的转化率可达10.29%,环己醇和环己酮的选择性达85.75%,优于该反应体系使用的工业催化剂对活性和选择性的指标要求。此外,X射线光电子能谱仪表征结果显示,当埃洛石负载的纳米金平均粒径处于2~5nm时,金元素主要以Au0 的形式存在。

关键词: 催化载体, 催化剂, 埃洛石, 金纳米粒子, 环己烷液相选择性氧化

Abstract:

Halloysite nanotubes (HNTs) are natural clay compounds with unique physical structures and chemical properties. In this paper, halloysite (PHNTs)-supported gold nanoparticles were obtained by using purified and PDDA modified halloysite as carrier to support the pre-prepared sol with controlled gold size. The concentration and volume of the chloroauric acid were adjusted to achieve effective regulation of the supported gold size. Transmission electron microscopy (TEM) images confirmed that the gold nanoparticles were well-dispersed on PHNTs and the average sizes of the gold nanoparticles were below 2nm, 2—5nm, and over 5nm respectively. The liquid phase selective oxidation of cyclohexane was used as a model reaction, and the activity and the selectivity to cyclohexanol and cyclohexanone using the prepared different-sized supported gold nanoparticles were evaluated. The results showed that PHNTS-supported gold nanoparticles with sizes between 2nm to 5nm exhibited excellent catalytic activity and selectivity for the selective oxidation of cyclohexane at 170℃ and 2.0MPa for 2h, and the conversion of cyclohexane and selectivity for cyclohexanol and cyclohexanone achieved 10.29% and 85.75% respectively, which is superior to the requirements of industrial catalysts. XPS characterization results showed that the gold particles with sizes of 2—5nm mainly existed as Au0.

Key words: catalyst support, catalyst, halloysite, gold nanoparticles, cyclohexane oxidation

中图分类号: 

京ICP备12046843号-2;京公网安备 11010102001994号
版权所有 © 《化工进展》编辑部
地址:北京市东城区青年湖南街13号 邮编:100011
电子信箱:hgjz@cip.com.cn
本系统由北京玛格泰克科技发展有限公司设计开发 技术支持:support@magtech.com.cn