CuO纳米线上支撑的尺寸选择的Pd纳米颗粒的热氧化：CuO-Pd界面的作用,Chemistry of Materials

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CuO纳米线上支撑的尺寸选择的Pd纳米颗粒的热氧化：CuO-Pd界面的作用
Chemistry of Materials ( IF 7.2 ) Pub Date : 2017-07-10 00:00:00 , DOI: 10.1021/acs.chemmater.7b02242
Stephan Steinhauer ₁ , Junlei Zhao ₂ , Vidyadhar Singh ₁ , Theodore Pavloudis ₃ , Joseph Kioseoglou ₃ , Kai Nordlund ₂ , Flyura Djurabekova ₂ , Panagiotis Grammatikopoulos ₁ , Mukhles Sowwan ₁

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负载在金属氧化物材料上的多相纳米催化剂的结构及其在氧化/还原过程中的形态变化在决定最终的催化活性中起着至关重要的作用。本文中，我们通过结合原位环境透射电子显微镜（TEM），非原位实验和从头算研究了负载在CuO纳米线上的Pd纳米粒子的热氧化机理。密度泛函理论（DFT）计算。通过几何相分析辅助的高分辨率TEM成像，可以分析部分氧化，完全氧化且具有亚表面位错的独特洋葱状Pd纳米颗粒。此外，已经发现在PdO纳米颗粒和CuO纳米线载体之间的优选的晶体取向。因此，CuO-Pd界面对于Pd纳米粒子的热氧化至关重要，这已得到电子能量损失谱和DFT计算的证实。后者显示出相当低的能垒，使氧渗透到CuO-Pd界面的Pd晶格中，从而促进了纳米粒子的氧化。将获得的结果与有关不同材料系统的文献报告进行比较，

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Thermal Oxidation of Size-Selected Pd Nanoparticles Supported on CuO Nanowires: The Role of the CuO–Pd Interface

The structure of heterogeneous nanocatalysts supported on metal oxide materials and their morphological changes during oxidation/reduction processes play a crucial role in determining the resulting catalytic activity. Herein, we study the thermal oxidation mechanism of Pd nanoparticles supported on CuO nanowires by combining in situ environmental transmission electron microscopy (TEM), ex situ experiments, and ab initio density functional theory (DFT) calculations. High-resolution TEM imaging assisted by geometric phase analysis enabled the analysis of partially oxidized, fully oxidized, and distinct onion-like Pd nanoparticles with subsurface dislocations. Furthermore, preferential crystalline orientations between PdO nanoparticles and the CuO nanowire support have been found. Hence, the CuO–Pd interface is crucial for the thermal oxidation of Pd nanoparticles, as corroborated by electron energy loss spectroscopy and DFT calculations. The latter revealed a considerably lower energy barrier for penetration of oxygen into the Pd lattice at the CuO–Pd interface, promoting nanoparticle oxidation. The obtained results are compared with those of literature reports on different material systems, and potential implications for catalysis and chemoresistive sensing applications are discussed.

更新日期：2017-07-11

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