催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (3): 210-216.

• 研究论文 • 上一篇    下一篇

多壁碳纳米管负载铂的甲苯加氢脱芳催化剂

周敏,林国栋,张鸿斌   

  1. 厦门大学化学化工学院固体表面物理化学国家重点实验室, 福建厦门 361005
  • 收稿日期:2007-03-25 出版日期:2007-03-25 发布日期:2007-03-25

Pt Catalyst Supported on Multiwalled Carbon Nanotubes for Hydrogenation-Dearomatization of Toluene

ZHOU Min, LIN Guodong, ZHANG Hongbin*   

  1. State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
  • Received:2007-03-25 Online:2007-03-25 Published:2007-03-25

PDF

1232

被引次数

72

摘要： 以多壁碳纳米管(CNTs)为载体制备了负载型Pt催化剂 Pt/CNTs并将其用于催化甲苯加氢脱芳(HDA)反应. 结果表明,在1.0%Pt/CNTs催化剂上,在0.4 MPa, 373 K, PhCH3/H2摩尔比=6/94和GHSV=120 L/(h·g)的反应条件下,甲苯转化率可达100%, 比反应速率为 0.0523 mmol/(s·m2), 分别是γ-Al2O3和AC负载各自最佳Pt负载量催化剂1.4%Pt/γ-Al2O3 和2.4%Pt/AC上相应值的1.17 和 1.18倍. 甲苯加氢产物全部为甲基环己烷,其他可能的加氢产物均在气相色谱检测限以下. 催化剂的表征研究揭示,用CNTs代替γ-Al2O3或AC作为载体并不会引起所负载Pt催化剂上甲苯HDA反应的表观活化能发生明显变化. 与γ-Al2O3或AC负载的相应催化剂相比,一方面, CNTs负载的Pt催化剂易于在较低温度下还原活化,并且其工作态催化剂表面催化活性Pt物种(Pt0)所占表面Pt摩尔分率有所提高; 另一方面, CNTs负载的Pt催化剂对H2具有较高的吸附/活化和储存能力. 这些促进效应对催化剂HDA活性的提高都有重要贡献.

关键词: 多壁碳纳米管, 铂, 负载型催化剂, 甲苯, 加氢脱芳

Abstract: Using home-made multiwalled carbon nanotubes (CNTs) as the support, the Pt/CNTs catalyst was prepared by an incipient wetness method. Performance of the catalyst for hydrogenation-dearomatization (HDA) of toluene was evaluated and compared with the reference catalysts supported on γ-Al2O3 and activated carbon (AC). Over the 1.0%Pt/CNTs catalyst under the reaction conditions of 0.4 MPa, 373 K, PhCH3/H2=6/94 (mol/mol) and GHSV=120 L/(h·g), the observed conversion of toluene HDA reached 100%, and the corresponding specific reaction rate was 0.0523 mmol/(s·m2). This value was 1.17 and 1.18 times that of the 1.4%Pt/γ-Al2O3 and 2.4%Pt/AC catalysts with the respective optimal Pt loading, respectively. It was experimentally found that using CNTs in place of γ-Al2O3 or AC as the support of the catalyst did not cause a significant change in the apparent activation energy for the toluene HDA reaction but led to a slight increase in concentration of catalytically active Pt species (Pt0) at the surface of the functioning catalyst. In addition, the Pt/CNTs catalyst could reversibly adsorb a greater amount of hydrogen under atmospheric pressure at temperatures from room temperature to 573 K. This unique feature would help to generate a microenvironment with higher stationary state concentration of active hydrogen-adspecies at the surface of the functioning catalyst. These effects favored the toluene HDA reaction.

Key words: multiwalled carbon nanotube, platinum, supported catalyst, toluene, hydrogenation-dearomatization