Seo Okkyun, Kim Jaemyung, Tayal Akhil, Song Chulho, Kumara L S R, Dekura Shun, Kobayashi Hirokazu, Kitagawa Hiroshi, Sakata Osami
Synchrotron X-ray Group, Research Center for Advanced Measurement and Characterization, National Institute for Materials Science 1-1-1 Kouto Sayo Hyogo 679-5148 Japan
Synchrotron X-ray Station at SPring-8, Research Network and Facility Services Division, National Institute for Materials Science 1-1-1 Kouto Sayo Hyogo 679-5148 Japan.
RSC Adv. 2019 Jul 9;9(37):21311-21317. doi: 10.1039/c9ra02942g. eCollection 2019 Jul 5.
We investigated the relationship between crystalline disorder and electronic structure deviations of Pd nanoparticles (NPs) and their hydrogen storage properties as a function of their particle diameter (2.0, 4.6 and 7.6 nm) using various synchrotron techniques. The lattice constant of the 2.0 nm-diameter Pd NPs was observed to be larger than that of the 4.6 or 7.6 nm-diameter Pd NPs. With increasing particle diameter the structural ordering was improved, the lattice constant and atomic displacement were reduced and the coordination numbers increased, as determined using high-energy X-ray diffraction, reverse Monte Carlo modelling and X-ray absorption fine structure spectroscopy. The structural order of the core part of the larger NPs was also better than that of the smaller NPs. In addition, the bond strength of the Pd-H formation increased with increasing particle diameter. Finally, the surface order of the Pd NPs was related to enhancement of the hydrogen storage capacity and Pd-H bond strength.
我们使用各种同步加速器技术，研究了钯纳米颗粒（NPs）的晶体无序与电子结构偏差之间的关系，以及它们作为粒径（2.0、4.6和7.6纳米）函数的储氢性能。观察到直径为2.0纳米的钯纳米颗粒的晶格常数大于直径为4.6或7.6纳米的钯纳米颗粒的晶格常数。使用高能X射线衍射、反向蒙特卡罗建模和X射线吸收精细结构光谱测定，随着粒径的增加，结构有序性得到改善，晶格常数和原子位移减小，配位数增加。较大纳米颗粒核心部分的结构有序性也比较小纳米颗粒的更好。此外，钯-氢形成的键强度随粒径增加而增加。最后，钯纳米颗粒的表面有序性与储氢容量和钯-氢键强度的增强有关。
