Ce助剂对V/SiO2催化CO2氧化乙苯脱氢性能的影响
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9...
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Published in | 物理化学学报 Vol. 30; no. 2; pp. 351 - 358 |
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Main Author | |
Format | Journal Article |
Language | Chinese |
Published |
太原理工大学化学化工学院,太原,030024%太原理工大学化学化工学院,太原030024
2014
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%太原理工大学精细化工研究所,太原,030024%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 |
Subjects | |
Online Access | Get full text |
ISSN | 1000-6818 |
DOI | 10.3866/PKU.WHXB201312021 |
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Summary: | 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. |
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Bibliography: | 11-1892/06 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 V^5+ to V^3+. 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 COJEB molar r |
ISSN: | 1000-6818 |
DOI: | 10.3866/PKU.WHXB201312021 |