物理化学学报 >> 1999, Vol. 15 >> Issue (07): 613-618.doi: 10.3866/PKU.WHXB19990707

研究论文 上一篇    下一篇

氧化镍与载体相互作用对乙烷氧化脱氢的影响

陈铜, 李文钊, 于春英   

  1. 中国科学院大连化学物理研究所,大连 116023
  • 收稿日期:1998-09-30 修回日期:1999-01-11 发布日期:1999-07-15
  • 通讯作者: 李文钊

Investigation of the Interaction between NiO and Support,γ-Al2O3,for Oxidative Dehydrogenation of Ethane

Chen Tong, Li Wen-Zhao, Yu Chun-Ying   

  1. Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023
  • Received:1998-09-30 Revised:1999-01-11 Published:1999-07-15
  • Contact: Li Wen-Zhao

摘要:

研究了担载型催化剂NiO/γ-Al2O3的乙烷氧化脱氧(ODHE)性能,发现在400-500℃的考察温区内,担载型NiO较纯NiO的乙烯选择性有较大提高,保持在80%~90%之间,其中含17%Ni的样品500℃时乙烷的转化率为31%,乙烯选择性达82%.XRD、H2-TPR及原位磁测量结果表明:催化剂的活性相是与载体相互作用较小的、处于表层的微晶态NiO,NiO中非化学计量氧仍为活性氧物种.催化剂焙烧温度的提高,一方面降低了活性相中非化学计量氧量,同时加剧了NiO与载体γ-Al2O3的相互作用,二者均使活性降低.O2-TPD研究表明:与纯NiO相比,在Nio/γ-Al2O3中,其非化学计量氧的脱附温度发生变化,其中,α氧脱附温度向低温移动约50℃,而对乙烯选择性有关的β氧的脱出则向高温区移动了约200℃,正好与反应温区对应,进一步证实非化学计量氧与ODHE反应之间存在对应关系,上述结果表明那些对氧化镍还原有一定的阻碍作用,尤其阻碍镍深度还原(Ni2+→Ni0)的载体对促进反应的乙烯选择性是有利的.

关键词: NiO/γ-Al2O3, 乙烷, 氧化脱氢, 反应机理, 金属-载体相互作用

Abstract:

The catalytic behavior of alumina-supported NiO catalysts for oxidative dehydrogenation of ethane (ODHE) has been investigated in the temperature range of 400 500℃ A much better improvement of selectivity towards ethylene can be observed, i e. the selectivity of 82%~92% for ethylene can be maintained. The optimum yield of ethylene of 25.3% is obtained over 17% NiO/γ-Al2O3 at 500℃. It is suggested that the NiO of non MSSI(Metal-support strong interaction)is the active phase and the nonstoichiometric oxygen in NiO lattice is the active oxygen species for ODHE. Comparing the O2-TPD spectra of NiO with NiO/γ-Al2O3, the high selectivity for ethylene over the alumina-supported NiO catalysts can be explained.

Key words: NiO/γ-Al2O3, Ethane, Oxidative dehydrogenation, Metal-support interaction