摘要
在镍基催化剂上进行了乙烷氧化脱氢制乙烯的研究.结果表明,浸渍法制备的催化剂性能最佳.以浸渍法引入CeO2后,催化剂的低温反应活性显著提高.采用O2-TPD-MS、TPR和XPS等表征技术对催化剂进行了表征,结果显示:在ODE反应中,在低温下起主导作用的是"非化学计量氧"(O2-、O-和O22-);在高温下起主导作用的是晶格氧;CeO2的添加减弱了NiO与载体-γAl2O3间的强相互作用,提高了镍物种在载体上的分散度,高分散于催化剂表面的微晶NiO的量明显增加,此物种有利于催化剂的低温活性;影响了催化剂表面氧物种的分布,表面的晶格氧的相对浓度提高了,非化学计量氧的相对浓度降低了.
Oxidative suits showed that the dehydrogenation of ethane to ethylene （ODE） was investigated over Ni-based catalyst. The recatalyst prepared by impregnation has the best catalytic performance. Introduction of CeO2 by impregnation favors the increase of catalytic activity at lower temperature. Characterization of O2-TPD-MS , TPR and XPS revealed that the non-stoiehiometrie oxygen speeies（O2^-, O^- and O2^2- ） played a critical role in the catalyst activity at relative low temperature, while the surface lattice oxygen species dominated at relative high temperature; The loading of CeO2 reduced the reaction between NiO and γ-Al2O3, promoted the distribution of Ni species on the carrier, thus the amount of highly-distributed NiO microcrystaUine which benefited the lower temperature activity was enhanced. Also CeO2 influenced the distribution of surface oxygen species, which mean that the relative content of surface lattice oxygen was increased; however the content of non-stoichiometric oxygen was decreased.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2007年第4期344-350,共7页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金资助项目(20203012)
广东省自然科学基金团队项目(4205301)
广东省科技计划项目(2004B33401003
2005B10201053)
广州市科技计划项目(2006J1-CO501)
关键词
乙烷
氧化脱氢
乙烯
镍基催化剂
氧物种
Ethane
Oxidative dehydrogenation
Ethane
Ni-based catalyst
Oxygen species
