如何Pt影响H2反应在高表面积的Pt/CeO2粉末催化剂表面
Jaeha Lee1, Peter Tieu2, Jordan Finzel1
1Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States.
JACS Au
|September 1, 2023
概括
(Pt) 添加到 (CeO2) 增强 (H2) 反应通过促进溢出和改变表面机制. 粉末催化剂的空间异质性决定了Ptt.
科学领域:
- 不同质的催化剂.
- 表面科学是一门科学.
- 材料化学 材料化学
背景情况:
- 像 (Pt) 一样,组金属 (PGM) 增强了 (CeO2) 氧化还原反应.
- 模型研究表明,PGMs有助于H2解离和溢出到CeO2表面.
- 了解PGM对粉末催化剂的影响,与模型系统不同,至关重要.
研究的目的:
- 研究Pt纳米集群和单个原子在Pt/CeO2粉末催化剂上的H2反应的机制.
- 将模型系统的发现与真实的粉末催化剂行为进行协调.
- 阐明空间异质性在PGM促进反应中的作用.
主要方法:
- 控制Pt/CeO2粉末催化剂的合成.
- 温度编程降低 (TPR) 来研究H2的消耗.
- 在现场红外光谱 (IR) 和电子能量损失光谱 (EELS) 进行机械洞察.
主要成果:
- 即使在Pt负载较低的情况下,Pt也显著提高了H2消耗率,这表明溢出超出了Pt-CeO2接口.
- Pt改变了H2的激活机制,影响了Ce3+,氧气空缺和水的形成速度.
- Ce3+形成位于Pt/CeO2中的CeO2-CeO2边界,与纯CeO2.2上的同质分布不同.
- 在CeO2-CeO2边界的表面重建有助于更快的H2消耗.
结论:
- 粉末催化剂的空间异质性极大地影响了PGM促进的H2反应在CeO2.
- Pt的影响超越了直接接口,涉及溢出和表面重建.
- 这项研究弥合了模型研究和实际粉末催化剂应用之间的差距.
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