物理化学学报 >> 2014, Vol. 30 >> Issue (2): 351-358.doi: 10.3866/PKU.WHXB201312021

催化和表面科学 上一篇    下一篇

Ce助剂对V/SiO2催化CO2氧化乙苯脱氢性能的影响

张海新1, 陈树伟1,2, 崔杏雨3, 潘大海1, 秦张峰2, 王建国2   

  1. 1 太原理工大学化学化工学院, 太原030024;
    2 中国科学院山西煤炭化学研究所, 煤转化国家重点实验室, 太原030001;
    3 太原理工大学精细化工研究所, 太原030024
  • 收稿日期:2013-08-06 修回日期:2013-11-29 发布日期:2014-01-23
  • 通讯作者: 陈树伟, 崔杏雨 E-mail:csw603@163.com;cuixingyu@tyut.edu.cn
  • 基金资助:

    国家自然科学基金(51172154),山西省科技攻关项目(20130313001-3),煤转化国家重点实验室开放课题基金(J12-13-603)及山西省自然科学(青年)基金(2012021006-2)资助

Effect of Ce Promoter on Catalytic Performance of V/SiO2 in Oxidative Dehydrogenation of Ethylbenzene with Carbon Dioxide

ZHANG Hai-Xin1, CHEN Shu-Wei1,2, CUI Xing-Yu3, PAN Da-Hai1, QIN Zhang-Feng2, WANG Jian-Guo2   

  1. 1 College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China;
    2 State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, P. R. China;
    3 Institute of Special Chemicals, Taiyuan University of Technology, Taiyuan 030024, P. R. China
  • Received:2013-08-06 Revised:2013-11-29 Published:2014-01-23
  • Contact: CHEN Shu-Wei, CUI Xing-Yu E-mail:csw603@163.com;cuixingyu@tyut.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51172154), Science and Technology Project of Shanxi Province, China (20130313001-3), Foundation of State Key Laboratory of Coal Conversion, China (J12-13-603), and Shanxi Province Science Foundation for Youths, China (2012021006-2).

摘要:

通过N2吸附、X射线衍射(XRD)、X射线光电子能谱(XPS)、H2程序升温还原(H2-TPR)、CO2程序升温脱附(CO2-TPD)和热重分析(TGA)等多种表征手段和催化反应性能评价,研究了铈助剂的添加对V/SiO2催化CO2氧化乙苯脱氢性能的影响. 结果表明,Ce助剂不仅提高了催化剂活性组分分散性和氧化还原性能,抑制了钒物种的深度还原,而且增强了催化剂碱性和CO2吸附能力,减缓了积炭生成,从而显著提高了V-Ce/SiO2对CO2氧化乙苯脱氢反应的催化活性和稳定性. 在本实验中,V(0.8)-Ce(0.25)/SiO2催化剂表现出最佳的催化性能,苯乙烯(ST)收率可达55.6%,选择性为98.5%,反应12 h 后,催化剂活性基本不变,与惰性N2气氛比较,CO2明显促进了乙苯脱氢反应,归因于CO2能保持催化剂表面钒物种的高价态.

关键词: 氧化铈, 负载型钒催化剂, 二氧化碳, 乙苯脱氢, 苯乙烯

Abstract:

The effect of a Ce promoter on the catalytic properties of V/SiO2 was investigated for the oxidative dehydrogenation of ethylbenzene (EB) to styrene (ST) with CO2 (CO2-ODEB). The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR), CO2 temperature-programmed desorption (CO2-TPD), and thermogravimetric analyses (TGA). It was found that incorporation of Ce into V/SiO2 increased the dispersion of active V species, enhanced the redox properties of the system, and inhibited deep V reduction of V5+ to V3+ . The Ce promoter also improves the basicity of V/SiO2 and CO2 adsorption on the catalyst, and suppresses coke formation. The addition of a Ce promoter greatly improves the catalytic activity and stability of V/SiO2 towards CO2-ODEB. The ST yield and selectivity reach 55.6% and 98.5%, respectively, for CO2-ODEB over the most efficient catalyst, V(0.8)Ce(0.25)/SiO2, at 550℃, and a CO2/EB molar ratio of 20. Moreover, after reaction for 12 h, the V(0.8)Ce(0.25)/SiO2 still shows stable catalytic activity. The ST yield in CO2 is higher than that in an inert N2 atmosphere, showing the significant promoting effect of CO2 on EB dehydrogenation; this is because CO2 is a soft oxidant and can effectively keep/regain the high valence of V for high activity with CO2-ODEB.

Key words: Cerium oxide, Supported vanadium oxide catalyst, Carbon dioxide, Ethylbenzene dehydrogenation, Styrene

MSC2000: 

  • O643