物理化学学报 >> 2014, Vol. 30 >> Issue (5): 950-956.doi: 10.3866/PKU.WHXB201403111

催化和表面科学 上一篇    下一篇

组合型Pt/TiO2催化剂用于低温催化甲苯完全氧化

敖平, 许响生, 徐潇潇, 李加衡, 严新焕   

  1. 浙江工业大学绿色化学合成技术国家重点实验室培育基地, 杭州310014
  • 收稿日期:2013-12-06 修回日期:2014-03-11 发布日期:2014-04-25
  • 通讯作者: 严新焕 E-mail:xinhuanyan139@hotmail.com
  • 基金资助:

    国家高技术研究发展计划项目(863)(2013AA065005)资助

Low-Temperature Total Oxidation of Toluene over Assembled Pt/TiO2 Catalyst

AO Ping, XU Xiang-Sheng, XU Xiao-Xiao, LI Jia-Heng, YAN Xin-Huan   

  1. State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, P. R. China
  • Received:2013-12-06 Revised:2014-03-11 Published:2014-04-25
  • Contact: YAN Xin-Huan E-mail:xinhuanyan139@hotmail.com
  • Supported by:

    The project was supported by the National High Technology Research and Development Program of China (863) (2013AA065005).

摘要:

将均匀分布的纳米Pt 粒子直接吸附到TiO2载体上,即制得了组合型Pt/TiO2催化剂(Pt/TiO2-AS). 与浸渍法制备的Pt/TiO2催化剂(Pt/TiO2-WI)比较,Pt/TiO2-AS催化剂在催化甲苯完全氧化反应中表现出了很好的催化性能,甲苯转化率为100%时的反应温度低至150 ℃,而且即使在较高甲苯浓度和较高气体空速下,该催化剂也能保持较好的催化性能. 通过X射线衍射(XRD)、N2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、氢气程序升温还原(H2-TPR)及傅里叶变换红外(FTIR)光谱等对两种Pt/TiO2催化剂的结构和表面性能进行了表征. 结果表明组合型Pt/TiO2-AS催化剂粒径小(2.5 nm),活性组分主要以Pt0形式存在且分布在载体表面,而且载体表面Ti―O键活化使催化剂具有较强的催化氧化能力. 另外,活性中心的价态变化(Pt0→Ptδ+)是导致Pt/TiO2-AS催化剂失活的主要原因.

关键词: 铂, 二氧化钛, 组合型催化剂, 甲苯, 完全氧化

Abstract:

A highly active assembled Pt/TiO2 catalyst (Pt/TiO2-AS) was synthesized using a simple directadsorption method, in which uniformly dispersed Pt nanoparticles were directly loaded on a TiO2 support. Compared with Pt/TiO2 produced by wet impregnation (Pt/TiO2-WI), the Pt/TiO2-AS catalyst exhibited higher activity in the total oxidation of toluene, with a toluene conversion to CO2 and H2O of 100% at 150 ℃. The high activity remained even at high toluene concentrations and gas hourly space velocities. The properties of the synthesized catalysts were characterized using X- ray diffraction (XRD), N2 adsorption- desorption (Brunauer-Emmett-Teller (BET) method), transmission electron microscopy (TEM), X- ray photoelectron spectroscopy (XPS), temperature-programmed reduction of H2 (H2-TPR), and Fourier-transform infrared (FTIR) spectroscopy. The results showed that the Pt/TiO2-AS crystallites were smaller than those of Pt/TiO2-WI, with fine dispersion, greater Pt0 exposure on the support surface, and more active Ti―O bands, giving more oxygen vacancies and reactive oxygen species. The valence states of the active centers changed significantly (Pt0→Ptδ+) during stability tests; this is the main reason for the deactivation of the Pt/TiO2-AS catalyst.

Key words: Platinum, Titanium dioxide, Assembled catalyst, Toluene, Total oxidation

MSC2000: 

  • O643