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Hydrogen diffusion in ceria: solid state NMR, combined scattering and spectroscopic studies, and ab initio calculations

Hydrogen diffusion in ceria: solid state NMR, combined scattering and spectroscopic studies, and ab initio calculations

来源:Arxiv_logoArxiv
英文摘要

Ceria has been extensively studied since it has many applications in diverse research fields. However, the mechanism of the hydrogen dynamics, especially the diffusion kinetics on a microscopic level is still unclear as the experimental data has been very limited. In this work, the CeO$_2$-H interaction has been comprehensively studied by a combination of $^1$H NMR transverse relaxation time ($T_2$) measurement, neutron powder diffraction, quasi-elastic neutron scattering (QENS), X-ray total scattering, and ab initio calculations. Based on QENS measurements, the first direct evidence for hydrogen jump diffusions of the Chudley-Elliot type in the bulk ceria has been given, with a jump distance of ~3.98 angstrom. The theoretically calculated activation energy barriers $E_a$ for hydrogen diffusion are relatively low (less than 0.1 eV), further supporting that such hopping can readily occur. A larger barrier value of $E_a$ ~0.2 eV is directly estimated by $T_2$ NMR data, suggesting possible slower hydrogen dynamics with the pre-exponential factor $D_0$ of diffusion coefficient ~10$^{-11}$ m$^2/$s.

Zhichao Zhu、Xin Li、Ziru Ma、Yuanhua Xia、Ruizhi Qiu、Baijiang Lv、Guanyun Yan、Jianrong Zeng、Long Yang、Jianbo Ma、Benqiong Liu、Guangai Sun

物理学化学

Zhichao Zhu,Xin Li,Ziru Ma,Yuanhua Xia,Ruizhi Qiu,Baijiang Lv,Guanyun Yan,Jianrong Zeng,Long Yang,Jianbo Ma,Benqiong Liu,Guangai Sun.Hydrogen diffusion in ceria: solid state NMR, combined scattering and spectroscopic studies, and ab initio calculations[EB/OL].(2025-06-10)[2025-07-21].https://arxiv.org/abs/2506.08789.点此复制

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