氧化物中的振荡性氧化还原行为:通过Mars-van Krevelen机制循环地表重建和反应性调制
Xianhu Sun1,2, Dongxiang Wu1, Jianyu Wang1
1Department of Mechanical Engineering and Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902.
概括
由于循环重建,氧化铜 (CuO) 表面在 (H2) 下表现出自我切换的氧化还原行为. 这个过程调节了表面对水形成的反应性,影响了氧化物表面的化学成分.
科学领域:
- 表面科学是一门学科.
- 材料化学 材料化学
- 催化剂是一种催化剂.
背景情况:
- 表面重组和协调不和地点对于氧化物表面反应性至关重要.
- 了解动态表面过程对于设计高效的催化剂至关重要.
研究的目的:
- 为了研究H2下的CuO表面的振荡性氧化还原行为.
- 阐明表面重建和反应性调制的机制.
- 探索对操纵氧化物表面反应性的影响.
主要方法:
- 在现场环境传输电子显微镜 (TEM) 用于直接观察.
- 原子模型是用来理解表面现象的.
- 对氧化还原循环和表面重建动态的分析.
主要成果:
- 在H2下观察到富含氧和缺氧CuO表面重建之间的自我切换.
- 通过Mars-van Krevelen (MvK) 机制证明了H2O形成的表面循环激活和失活.
- 通过地下格子氧气扩散识别了缺氧表面的缓慢再氧化.
结论:
- 振荡性氧化还原行为是由表面离子活性和氧气补充缓慢的差异驱动的.
- 在氧化物表面的空间时间分离的氧化还原步骤调节H2诱导的氧气损失和补充.
- 调整氧化还原步骤的分离提供了一条控制氧化物表面活性的途径.
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