促进了银的选择性乙烯环氧化
Anika Jalil1, Elizabeth E Happel2, Laura Cramer2
1Department of Chemical Engineering, University of California, Santa Barbara, CA, USA.
Science (New York, N.Y.)
|February 20, 2025
概括
在白银催化剂中 doping 通过激活氧气来增强乙烯环氧化选择性. 这种方法提供了无的途径,并改善了现有的促进反应,推进了选择性氧化催化剂设计.
科学领域:
- 不同质的催化
- 表面科学
- 材料科学
背景情况:
- 乙烯环氧化是一个重要的工业过程,历来依赖于 (Cl) 促进银 (Ag) 催化剂.
- 传统的促进剂 (Cs,Re,Mo) 增强选择性,但表现出对Cl的复杂依赖性,阻碍了优化和机械理解.
- 由于促进剂和的复杂相互作用,在乙烯环氧化中实现高选择性 (~90%) 仍然是一个挑战.
研究的目的:
- 通过理论指导的单原子合金方法,确定乙烯环氧化中的银催化剂的新型促进剂.
- 调查 (Ni) 作为Ag中的剂,以促进乙烯的选择性氧化.
- 探索Ni在氧气激活中的作用及其对催化剂选择性的影响,无论是有还是没有共流.
主要方法:
- 理论建模指导了 (Ni) 作为银 (Ag) 催化剂中的单原子剂的选择.
- 进行了表面科学实验,以研究在Ni-doped Ag (NiAg) 表面上的氧吸附/脱吸.
- 在乙烯环氧化中合成并测试了具有控制Ni的支持Ag催化剂 (1:200 Ni:Ag比率).
主要成果:
- 在Ag中补充促进了分子氧 (O2) 激活,而没有强烈的氧 (O) 结合,这对于选择性氧化至关重要.
- NiAg表面表现出容易吸附/脱附和稳定非选择性氧物种.
- 在没有Cl共流的情况下,NiAg催化剂 (1:200比) 在乙烯环氧化中实现了~25%的选择性增加.
- NiAg与Cl合作,产生额外的~10%的初始选择性增强.
结论:
- 被确定为乙烯环氧化中的银催化剂的有效补剂,通过O2激活促进选择性氧化.
- NiAg催化剂提供了一个有前途的途径来增强选择性,减少或消除对的需求.
- 和Cl之间的协同效应表明了优化乙烯环氧化催化剂的新途径.
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