In Situ Strain Evolution on Pt Nanoparticles during Hydrogen Peroxide Decomposition
In Situ Strain Evolution on Pt Nanoparticles during Hydrogen Peroxide Decomposition
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DOI：
10.1021/acs.nanolett.0c03005
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发表时间：
2020-12-09
期刊：
影响因子：
10.8
通讯作者：
Kim, Hyunjung
中科院分区：
文献类型：
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作者：
Choi, Sungwook;Chung, Myungwoo;Kim, Hyunjung
对催化反应过程中结构变化的基本了解对于理解潜在的机理和优化效率至关重要。表面能及相关的催化机理被广泛研究。然而，由催化过程引起的催化剂晶格变形还不是很清楚。在这里，我们研究了单个铂(铂)纳米颗粒(NP)在原位氧化和还原反应下的布拉格相干衍射成像的应变。当铂纳米颗粒暴露在典型的氧化剂和氧还原反应过程中的中间体H_2O_2中时，在(111)Bragg反射处观察到在纳米颗粒表面和内部的总应变分布的交替。相比之下，相对较小的变化出现在(200)反射中。通过密度泛函理论计算，将各向异性晶格应变归结为H_2O_2在铂纳米颗粒表面的吸附和分解所产生的应力。我们的研究为深入了解这一系统中的活动-结构关系提供了更深入的见解。
Fundamental understanding of structural changes during catalytic reactions is crucial to understanding the underlying mechanisms and optimizing efficiencies. Surface energy and related catalytic mechanisms are widely studied. However, the catalyst lattice deformation induced by catalytic processes is not well understood. Here, we study the strain in an individual platinum (Pt) nanoparticle (NP) using Bragg coherent diffraction imaging under in situ oxidation and reduction reactions. When Pt NPs are exposed to H2O2, a typical oxidizer and an intermediate during the oxygen reduction reaction process, alternating overall strain distribution near the surface and inside the NP is observed at the (111) Bragg reflection. In contrast, relatively insignificant changes appear in the (200) reflection. Density functional theory calculations are employed to rationalize the anisotropic lattice strain in terms of induced stress by H2O2 adsorption and decomposition on the Pt NP surface. Our study provides deeper insight into the activity-structure relationship in this system.