物理化学学报 >> 2012, Vol. 28 >> Issue (06): 1448-1454.doi: 10.3866/PKU.WHXB201204011

催化和表面科学 上一篇    下一篇

Pt/MOx-SiO2 (M=Ce, Zr, Al)催化剂对CO和C3H8氧化性能的影响

周菊发, 赵明, 彭娜, 杨铮铮, 龚茂初, 陈耀强   

  1. 四川大学化学学院, 绿色化学与技术教育部重点实验室, 成都 610064
  • 收稿日期:2012-01-12 修回日期:2012-03-19 发布日期:2012-05-17
  • 通讯作者: 陈耀强 E-mail:nic7501@scu.edu.cn
  • 基金资助:

    国家自然科学基金(21173153)和四川省科技厅科技支撑项目(2011GZ0035)资助

Performance Effect of Pt/MOx-SiO2 (M=Ce, Zr, Al) Catalysts for CO and C3H8 Oxidation

ZHOU Ju-Fa, ZHAO Ming, PENG Na, YANG Zheng-Zheng, GONG Mao-Chu, CHEN Yao-Qiang   

  1. Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
  • Received:2012-01-12 Revised:2012-03-19 Published:2012-05-17
  • Contact: CHEN Yao-Qiang E-mail:nic7501@scu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173153) and Science and Technology Department of Science and Technology Support Project of Sichuan Province, China (2011GZ0035).

摘要: 采用共沉淀法制备质量比为1:1的MOx-SiO2 (M=Ce, Zr, Al)复合氧化物, 以此为载体采用浸渍法制备了铂基氧化型催化剂. 考察了该系列催化剂在模拟柴油车尾气条件下, 经SiO2硫化前后对C3H8和CO的氧化性能. 用X射线衍射(XRD)、低温N2吸附-脱附、氨气/氧气/二氧化碳程序升温脱附(NH3/O2/CO2-TPD) 和X射线光电子能谱(XPS)等手段进行了表征. NH3-TPD证实催化剂表面存在多种酸中心, 硫化后催化剂表面中强酸中心增多. O2-TPD证实催化剂表面存在α和β氧物种, 硫化后催化剂表面氧脱附量减少. 其中Pt/Al2O3-SiO2表面酸性最弱和表面氧脱附量最大. XPS结果表明新鲜催化剂经硫化后会使催化剂表面Pt 的结合能降低. 活性测试结果表明, 三种催化剂对CO和C3H8的催化氧化活性均较好, 其中Pt/ZrO2-SiO2抗SiO2中毒性能最佳, 具有良好的应用前景.

关键词: 共沉淀, 复合氧化物, 铂, 氧化型催化剂, 柴油车, 表面酸性, SO2中毒

Abstract: MOx-SiO2 (M=Ce, Zr, Al) mixed oxides with a MOx:SiO2 mass ratio of 1:1 were prepared by co-precipitation. Pt-only diesel oxidation catalysts supported on these mixed oxides were obtained by the incipient wetness method. The catalytic activities in simplified diesel exhaust gas before and after SO2 treatment were analyzed. The catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, NH3/O2/CO2 temperature programmed desorption (NH3/O2/CO2-TPD) and X-ray photoelectron spectroscopy (XPS). The results of NH3-TPD suggested that the surface of the catalysts had multiple acidic sites, and the number of medium-strength acidic sites increased following treatment with SO2. The results of O2-TPD revealed that there were α and β oxygen species in the catalysts, and the amount of O2 desorption decreased for the SO2-treated catalysts. The Pt/Al2O3-SiO2 catalyst exhibited the lowest surface acidity and the largest amount of oxygen desorption. XPS indicated that the binding energy of Pt 4f5/2 decreased when the catalysts were treated with SO2. All the catalysts showed excellent activity for CO and C3H8, and the Pt/ ZrO2-SiO2 catalyst exhibited the best SO2 poisoning resistance, showing the potential for these catalysts to be applied in diesel oxidation.

Key words: Co-precipitation, Mixed oxide, Platinum, Oxidation catalyst, Diesel vehicle, Surface acidity, SO2 poisoning

MSC2000: 

  • O643