Citation: Chen Tong, Li Wen-Zhao, Yu Chun-Ying. Investigation of the Interaction between NiO and Support,γ-Al2O3,for Oxidative Dehydrogenation of Ethane[J]. Acta Physico-Chimica Sinica, 1999, 15(07): 613-618. doi: 10.3866/PKU.WHXB19990707
氧化镍与载体相互作用对乙烷氧化脱氢的影响
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．
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关键词:
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NiO/γ-Al2O3
- / 乙烷
- / 氧化脱氢
- / 反应机理
- / 金属-载体相互作用
English
Investigation of the Interaction between NiO and Support,γ-Al2O3,for Oxidative Dehydrogenation of Ethane
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.
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Key words:
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NiO/γ-Al2O3
- / Ethane
- / Oxidative dehydrogenation
- / Metal-support interaction
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