乙烯的室温环氧化在基于delafossite的AgNiO2纳米粒子上
Dmitry A Svintsitskiy1, Mikhail K Lazarev1, Elena M Slavinskaya1
1Boreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090, Novosibirsk, Russian Federation. sad@catalysis.ru.
Physical chemistry chemical physics : PCCP
|August 1, 2023
概括
银氧化物 (AgNiO2) 在室温下对乙烯环氧化具有很高的选择性. 这种活动源于其独特的结构,含有白银空缺和独特的氧物种,使得有效的催化反应成为可能.
科学领域:
- 材料科学 材料科学 材料科学
- 催化剂是一种催化剂.
- 表面化学 表面化学
背景情况:
- 乙烯环氧化是一种重要的工业过程.
- 开发高效和选择性的乙烯环氧化催化剂具有显著的兴趣.
- 混合金属氧化物为催化应用提供可调节的特性.
研究的目的:
- 为了合成和描述一种新的银混合氧化物 (AgNiO2).
- 为了研究AgNiO2在室温乙烯环氧化中的催化活性.
- 阐明环氧化过程中涉及的表面特性和反应机制.
主要方法:
- 对于AgNiO2合成的共同沉.
- 粉末衍射 (PDF) 方法用于结构分析.
- 用乙烯 (C2H4) 和X射线光电谱 (XPS) 进行温度编程降低 (TPR) 进行表面特征.
主要成果:
- 通过共同沉合成的AgNiO2表现出室温活性,以高达70%的选择性为乙烯环氧化.
- 结构分析显示堆叠缺陷和白银空缺,导致非静态测量 (Ag/Ni < 1).
- 氧化物表面含有中间的白银物种 (类似Ag+) 和类似Ni3+的状态,其中核性 (晶格) 和电性 (与表面结合) 氧气物种都参与了反应.
结论:
- AgNiO2是室温乙烯环氧化的一个活性催化剂,这是由于其独特的缺陷结构和反应性氧物种的存在.
- 表面的弱结合的电友氧是环氧化活动的关键,而晶格氧则起着核友的作用.
- 在反应过程中,delafossite结构在室温下保持稳定,而Ag0形成和结构分解发生在更高的温度下.
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