乙烯
乙炔
催化作用
化学
选择性
碳氢化合物
吸附
焦炭
化学工程
无机化学
材料科学
有机化学
光化学
工程类
作者
Kyunglim Hyun,Seongho Yun,Minkee Choi
出处
期刊:ACS Catalysis
[American Chemical Society]
日期:2024-02-12
卷期号:14 (5): 2938-2948
标识
DOI:10.1021/acscatal.3c05474
摘要
Selective acetylene partial hydrogenation in an ethylene-rich stream plays a crucial industrial role in removing acetylene impurities from ethylene produced through hydrocarbon cracking. In this study, we investigated the distinct promotional effects of Ag and amorphous polyphenylene sulfide (Am-PPS) on Pd catalysts. The addition of Ag increased the electron density of Pd and reduced the size of the Pd ensemble, effectively inhibiting undesired side reactions, such as the overhydrogenation of ethylene to ethane and the hydro-oligomerization of acetylene into C4 and heavier paraffins (green oil). However, alloying with inactive Ag resulted in a reduced number of surface-exposed active Pd atoms, leading to a significant decrease in catalytic activity. On the other hand, surface modification of Pd with Am-PPS was very effective in suppressing ethylene overhydrogenation without compromising acetylene hydrogenation activity. Furthermore, it facilitated the removal of green oil from the catalyst surface before its transformation into coke, significantly retarding the catalyst deactivation. This can be attributed to the rapid cleaning of ethylene and green oil from the Pd surface through the competitive adsorption of the Am-PPS polymer chains. The advantages of each promoter can be synergistically combined through dual promotion. The resulting catalyst exhibited moderate activity, along with exceptionally high ethylene selectivity, and suppressed formation of carbonaceous deposits (both green oil and coke). These findings demonstrate the unique potential to design advanced selective hydrogenation catalysts by leveraging the advantages of both inorganic and organic promoters.
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