在CO和新加斯处理期间在Co/TiO2上的单个CoNPs的组成演变通过软XAS/X-PEEM解决了CO和新加斯处理
Chengwu Qiu1,2, Yaroslav Odarchenko1,2, Qingwei Meng3
1Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
ACS catalysis
|December 21, 2023
概括
纳米粒子 (NP) 尺寸影响费舍尔-托普施合成 (FTS) 催化剂性能. 较小的NP (≤12 nm) 保持金属化,而较大的NP (≥15 nm) 氧化,受氧空缺的影响.
科学领域:
- 不同质的催化剂.
- 纳米材料科学 纳米材料科学
- 表面化学 表面化学
背景情况:
- 纳米粒子 (NP) 的氧化还原状态对于费舍尔-托普施合成 (FTS) 催化剂的性能至关重要.
- 了解NP大小依赖的行为是优化FTS催化剂的关键.
研究的目的:
- 调查个人NP (6-24 nm) 的现场组成演变 (氧化物与金属状态).
- 阐明NP大小和氧空缺在CO/合成气处理过程中NP的氧化还原行为中的作用.
主要方法:
- 空间分辨率的X射线吸收光谱 (XAS) 和X射线光发射电子显微镜 (X-PEEM).
- 在CO和合成气处理期间进行现场分析,然后进行UHV火.
- O K-边缘测量以确定氧气空缺.
主要成果:
- 在CO处理过程中,较小的CoNPs (≤12 nm) 仍然是金属的,而较大的NP (≥15 nm) 则部分氧化.
- 合成气处理导致较大的NP减少,较小的NP氧化,表面再氧化是暂时的.
- 氧空缺 (Ovac) 被确定为影响CoNPs的氧化还原行为的关键因素.
结论:
- NP大小显著影响Co/TiO2 FTS催化剂的可还原性和反应性.
- 氧气空缺在调节NP的氧化还原特性方面发挥着关键作用.
- 这项研究为基于的FTS催化剂的物理化学特性提供了更深入的见解.
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