在白金表面上氧气添加物的移动性和反应性
Wei Wang1, Jie Zhang1, Fangfang Wang1
1State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
Journal of the American Chemical Society
|July 12, 2016
概括
氧气在表面的移动性是防止燃料电池中催化剂失活的关键. 了解这种表面扩散有助于催化剂的重新激活和耐毒性.
科学领域:
- 电化学
- 表面科学
- 材料科学
背景情况:
- (Pt) 催化剂被一氧化碳 (CO) 禁用是燃料电池的一个主要挑战.
- 了解Pt上的氧吸附和移动性对于CO氧化至关重要.
- 氧的表面流动性会影响催化剂的性能和寿命.
研究的目的:
- 在白金表面研究氧气附加物种的表面移动性.
- 确定氧气附加物种表面扩散系数.
- 阐明氧气附加物种在CO氧化和Pt催化剂抗毒中的作用.
主要方法:
- 使用纳米电极和超微电极技术.
- 从H2O吸附和CO反应中观察到氧气附加物种的表面移动性.
- 分析了对扫描速率的脱吸电荷依赖,以确定扩散系数.
主要成果:
- 氧的吸附电荷与扫描速率的平方根相成比例.
- 在25°C时,确定氧化物表面扩散系数为 (5.61 ± 0.84) × 10−10 cm2/s.
- 确定了二氧化碳氧化过程中的两个当前峰值,与二氧化碳氧化和氧气附加物种的表面流动性有关.
结论:
- 氧气附加物种的表面移动性是Pt催化剂抗毒和再激活的关键因素.
- 观察到的现象为维持燃料电池中的Pt催化剂效率提供了洞察力.
- 这项研究强调了表面动态在催化过程中的重要性.
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