在Au/TiO2氧化催化剂的周边部位受到反应剂氧气的抑制
Isabel Xiaoye Green1, Wenjie Tang, Monica McEntee
1Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States.
Journal of the American Chemical Society
|June 29, 2012
概括
支持二氧化的金纳米颗粒显示氧化反应的催化活性. 预氧化金纳米颗粒可以抑制一氧化碳的氧化,这是由于双催化位点的金原子具有正电荷.
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:
- 大量黄金在氧化反应中具有催化不活性.
- 在二氧化 (TiO2) 上支的金纳米粒子表现出意想不到的催化活性.
- 催化活性仅限于金纳米颗粒的周围,在那里它们与TiO2支进行接口.
研究的目的:
- 调查TiO2支持的金纳米粒子中催化活性的起源.
- 了解这些纳米材料上的CO氧化机制.
- 在催化过程中探索一个反应物种的自我抑制现象.
主要方法:
- 在低温 (120 K) 下对CO氧化反应速率的实验研究.
- 预氧化金纳米颗粒以诱导表面变化.
- 理论计算以建模电子结构和反应路径.
- 分析涉及黄金和TiO2的双催化场所.
主要成果:
- 支持TiO2的金纳米颗粒显示出氧化反应的显著催化活性.
- 在120 K的金纳米粒子预氧化时,CO氧化率降低了22倍.
- 前氧化导致氧气诱导的阳性电荷在周围的金原子.
- 理论计算证实,由于正电荷,在双催化位点对二氧化碳氧化的激活能量增加.
结论:
- 支持TiO2的黄金纳米颗粒的催化活性位于黄金和TiO2之间的接口 (周边) 上.
- 涉及黄金和Ti4+的双催化场有效地激活氧分子.
- 黄金纳米颗粒的先氧化导致CO氧化的自我抑制,通过创建带正电荷的黄金原子,增加激活能量.
相关概念视频
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