Promoting Effect of Cerium Oxide on the Catalytic Performance of Yttrium Oxide for Oxidative Coupling of Methane
Promoting Effect of Cerium Oxide on the Catalytic Performance of Yttrium Oxide for Oxidative Coupling of Methane
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DOI：
10.3389/fchem.2018.00581
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发表时间：
2018-11-22
影响因子：
5.5
通讯作者：
Towata, Atsuya
中科院分区：
文献类型：
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作者：
Haneda, Masaaki;Katsuragawa, Yuya;Towata, Atsuya
研究了CeO 2对中活性催化剂Y2 O3催化甲烷氧化偶联反应性能的促进作用。通过共沉淀法将CeO 2添加到Y2 O3中，不仅显著提高了CH 4的转化率，而且提高了OCM反应中C2-（C2 H6/C2 H4）的选择性。在750 ℃下的C-2产率从基于Y2 O3的5.6%增加到基于3mol%CeO2/Y2 O3的10.2%。CeO 2负载量的进一步增加导致CH 4非选择性氧化为CO2的增加。OCM反应的催化活性和H-2-TPR曲线中表面/表面下氧物种减少的H-2消耗量之间存在良好的相关性，表明高度分散的CeO 2颗粒可能在OCM反应中充当催化活性位点。O-16/O-18同位素交换反应表明，CeO 2在OCM反应中的有益作用是通过简单的杂原子交换机制促进活性氧物种的形成，从而促进CH 4的活化。
The promoting effect of CeO2 on the catalytic performance of Y2O3, which is moderately active catalyst, for the oxidative coupling of methane (OCM) reaction was investigated. The addition of CeO2 into Y2O3 by coprecipitation method caused a significant increase in not only CH4 conversion but also C-2 (C2H6/C2H4) selectivity in the OCM reaction. C-2 yield at 750 degrees C was increased from 5.6% on Y2O3 to 10.2% on 3 mol% CeO2/Y2O3. Further increase in the CeO2 loading caused an increase in non-selective oxidation of CH4 to CO2. A good correlation between the catalytic activity for the OCM reaction and the amount of H-2 consumption for the reduction of surface/subsurface oxygen species in the H-2-TPR profile was observed, suggesting the possibility that highly dispersed CeO2 particles act as catalytically active sites in the OCM reaction. The O-16/O-18 isotopic exchange reaction suggested that the beneficial role of CeO2 in the OCM reaction is to promote the formation of active oxygen species via the simple hetero-exchange mechanism, resulting in the promotion of CH4 activation.