在相同的金属负载下重新探索尺寸依赖的催化性能,并识别真正的活性物种:从单个原子,集群到纳米粒子
Jiankang Zhang1, Ye Ma2, Jiawen Yang3,4
1Interdisciplinary Research Center of Biology & Catalysis, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
ACS nano
|November 15, 2025
概括
(Pt) 催化剂在更大的颗粒大小下显示出更高的活性,挑战了之前的假设. 这项研究揭示了纳米集群和纳米颗粒是CO氧化活性场所,为大小依赖的催化提供了洞察力.
科学领域:
- 异种催化剂的异种催化
- 表面科学是一门学科.
- 材料化学 材料化学
背景情况:
- 尺寸依赖的催化是至关重要的,但复杂的,受金属负荷和支相互作用的影响.
- 对相同金属负载的尺寸效应的研究很少.
- 了解颗粒大小对催化活性的影响对于催化剂设计至关重要.
研究的目的:
- 为了研究 (Pt) 催化剂的尺寸依赖性催化,具有均的金属负载.
- 阐明单个原子 (SA),集群和纳米粒子在催化反应中的作用.
- 探索粒子大小,活性和反应机制之间的关系.
主要方法:
- 合成的SiO2支持的Pt催化剂具有不同的粒子大小 (SA,集群,纳米粒子) 在0.3%重量%的负载使用原子层沉积.
- 在CO氧化反应中探测了催化活性.
- 使用现场STEM,同位素标记和理论计算来跟踪动态过程和反应机制.
主要成果:
- 催化活性随着Pt粒子大小显著增加.
- 在CO氧化过程中观察到一个渐进的聚合-激活过程.
- Pt纳米团/纳米颗粒,而不是SA,被确定为活性物种.
- 由于动态尺寸转换和支封闭,实现了超高的耐用性 (>2160小时).
- 小分子的分裂能量与粒子大小和活性相关.
结论:
- Pt纳米集群/纳米颗粒是CO氧化,化和H2O2相关反应的主要活性场所.
- 催化剂颗粒大小是催化活性的一个关键描述因素.
- 动态重组和支效应有助于增强催化剂的耐用性.
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