Surface structure of yttrium-modified ceria catalysts and reaction pathways from ethanol to propene
Surface structure of yttrium-modified ceria catalysts and reaction pathways from ethanol to propene
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DOI：
10.1016/j.jcat.2014.04.017
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发表时间：
2014-07-01
影响因子：
7.3
通讯作者：
Iwamoto, Masakazu
中科院分区：
文献类型：
--
作者：
Hayashi, Fumitaka;Tanaka, Masashi;Iwamoto, Masakazu
研究了31种金属元素对氧化铈催化剂乙醇转化制丙烯反应活性的加和效应。钇的效果最好，丙烯产率对Y含量呈火山形依赖关系，在Y含量为Ce的20原子%时达到最大值。该催化剂是稳定的，由于非常小的碳沉积速率，约为母体CeO 2催化剂的1/100。水的加入使丙烯产率增加到30%，使乙烯产率降低到37%，并且不改变耐久性。Y/CeO 2催化剂的物理化学表征表明，活性催化剂的表面被Ce-2和Y2 O3的固溶体覆盖。脉冲实验表明，通过Tishchenko反应、酮化反应和Meerwein-Ponndorf-Verley还原反应，反应途径为乙醇->乙醛->乙酸乙酯->乙酸->丙酮2-丙醇->丙烯。(C)2014爱思唯尔公司All rights reserved.
The additive effect of 31 metals on activity of ceria catalysts was studied for the conversion of ethanol to propene. Yttrium gave the best results and the propene yield showed a volcano-shaped dependence on the Y amount, being maximized at 20 atom% Y to that of Ce. The catalyst was stable due to very small carbon deposition rate which was approximately 1/100 of that on the parent CeO2 catalyst. The water addition increased the propene yield to 30%, decreased the ethene yield to 37%, and did not change the durability. The physicochemical characterization of the Y/CeO2 catalysts indicated that the surface of active catalysts was covered with a solid solution of Ce-2 and Y2O3. Pulse experiments of various candidate compounds suggested that the reaction pathways were ethanol -> acetaldehyde -> ethyl acetate -> acetic acid -> acetone 2-propanol -> propene through Tishchenko reaction, ketonization, and Meerwein-Ponndorf-Verley reduction. (C) 2014 Elsevier Inc. All rights reserved.