不同质的催化剂不需要如此"异质":单分散的Pt纳米晶体通过结合形状控制的合成和通过合体再结晶的净化来实现
1Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Journal of the American Chemical Society
|January 29, 2013
概括
高纯度 (Pt) 纳米晶体与受控的方面被合成和净化. 这些模型催化剂在各种催化反应中揭示了面体依赖的反应性,为纳米级催化提供了洞察力.
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.
- 纳米技术 纳米技术
背景情况:
- 虽然研究了精确定义的 (Pt) 表面,但工业催化剂使用纳米颗粒用于高表面积.
- 理解纳米级催化剂对于开发高效的工业催化剂至关重要.
- 需要直接比较纳米尺度方面 ({111}和{100}).
研究的目的:
- 开发一种用于制备具有多样性形态的Pt纳米晶的一般合成方法.
- 为了净化合成的Pt纳米晶体,以便直接比较面反应性.
- 在各种反应中研究{111}和{100}方面的催化行为.
主要方法:
- 具有各种形态的Pt纳米晶体的一般合成.
- 使用"自我清洁"效应通过"合性再结晶"的Pt超晶体进行净化.
- 在酸的电氧化,CO氧化和电子转移反应中测试催化性能.
主要成果:
- 与Pt立方体相比,Pt八面体在酸电氧化中表现出更好的中毒耐受性.
- 在Pt纳米晶体上的CO氧化在低O2/CO比率下是结构不敏感的,但在富含O2的条件下是敏感的.
- 对于六酸 (III) /硫酸电子转移反应,Pt八面体显示的激活能量低于Pt立方体.
结论:
- 高质量的Pt纳米晶体具有选择性暴露的{111}和{100}方面,作为纳米级催化物的理想模型系统.
- 在电催化,气相和液相反应中观察到因子依赖的反应性.
- 这项工作弥合了延伸表面和纳米粒子催化之间的理解.
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