催化作用
脱水
材料科学
Crystal(编程语言)
化学工程
脱水反应
乙烯
高分辨率透射电子显微镜
化学
有机化学
纳米技术
计算机科学
生物化学
工程类
透射电子显微镜
程序设计语言
作者
Jiangang Lv,Di Wang,Luming Peng,Xuefeng Guo,Weiping Ding,Weimin Yang
出处
期刊:Catalysts
[Multidisciplinary Digital Publishing Institute]
日期:2023-06-12
卷期号:13 (6): 994-994
被引量:11
标识
DOI:10.3390/catal13060994
摘要
Highly efficient and stable catalysts are among the key factors in industrial ethanol dehydration to ethylene. Among the widely studied catalysts, alumina is the most suitable for industrial application. In this study, novel gamma alumina was synthesized by solvent protection and a hydrothermal procedure. HRTEM, XRD, FT-IR, NH3-TPD, H-D exchange, and 29Si MAS NMR were employed to compare the difference in physicochemical properties between the novel gamma alumina and commercial alumina. Characterization results show that the as-synthesized novel gamma alumina mainly exposes the high-energy crystal plane (111) while the commercial alumina mainly exposes the thermostatically stable (110) crystal plane. The dominating (111) plane, according to the characterizations, endows the novel gamma alumina with a higher density of surface hydroxyl groups, higher acid content, and higher surface energy compared to the commercial alumina. The catalytic performance of the two catalysts for industrial ethanol dehydration to ethylene was studied. The novel (111) plane-exposed alumina showed a higher yield of ethylene than commercial alumina under the same reaction conditions. This could be related to the difference in atomic arrangement and the unsaturated aluminum coordination of different crystal planes. Stability testing under severe reaction conditions (450 °C, 1 MPa, 4 h−1) indicates that novel gamma alumina shows better stability (catalyst life cycle increased by 50%) and produces less acetaldehyde as a byproduct. The effects of steam treatment on the catalytic performance were further investigated. The surface acidity and the catalytic performance of novel gamma alumina present a volcanic curve with the increase in steam treatment temperature. Under the optimal water vapor treatment temperature of 650 °C, the conversion of ethanol and selectivity of ethylene were both higher than 99%.
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