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| Main Authors: | , |
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| Format: | Preprint |
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2024
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| Online Access: | https://arxiv.org/abs/2411.06536 |
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| _version_ | 1866915012816142336 |
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| author | Stimac, Jared C. Goldman, Nir |
| author_facet | Stimac, Jared C. Goldman, Nir |
| contents | CeO$_2$ (ceria) is an attractive material for heterogeneous catalysis applications involving hydrogen due to its favorable redox activity combined with its relative impermeability to hydrogen ions and molecules. However, to date, many bulk ceria/hydrogen properties remain unresolved in part due to a scarcity of experimental data combined with quantum calculation results that vary according to the approach used. In this regard, we have conducted a series of Density Functional Theory (DFT) calculations utilizing generalized gradient (GGA), meta-GGA, and hybrid functionals as well as several corrections for electronic correlations, applied to a number of properties regarding hydrogen in bulk stoichiometic $\mathrm{CeO_2}$. Our calculations place reasonable bounds on the lattice constants, band gaps, hydrogen absorption energies, and O-H bond vibrational frequencies that can be determined by DFT. In addition, our results indicate that the activation energy barriers for hydrogen bulk diffusion are uniformly low ($ < 0.15 \ \mathrm{eV} $) for the calculation parameters probed here and that, in general, the effect of hydrogen tunneling is small at ambient temperatures. Our study provides a recipe to determine fundamental physical chemical properties of Ce-O-H interactions while also determining realistic ranges for diffusion kinetics. This can facilitate the determination of future coarse-grained models that will be able to guide and elucidate experimental efforts in this area. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_06536 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Quantum Calculations of Hydrogen Absorption and Diffusivity in Bulk $\mathrm{CeO_2}$ Stimac, Jared C. Goldman, Nir Materials Science Computational Physics CeO$_2$ (ceria) is an attractive material for heterogeneous catalysis applications involving hydrogen due to its favorable redox activity combined with its relative impermeability to hydrogen ions and molecules. However, to date, many bulk ceria/hydrogen properties remain unresolved in part due to a scarcity of experimental data combined with quantum calculation results that vary according to the approach used. In this regard, we have conducted a series of Density Functional Theory (DFT) calculations utilizing generalized gradient (GGA), meta-GGA, and hybrid functionals as well as several corrections for electronic correlations, applied to a number of properties regarding hydrogen in bulk stoichiometic $\mathrm{CeO_2}$. Our calculations place reasonable bounds on the lattice constants, band gaps, hydrogen absorption energies, and O-H bond vibrational frequencies that can be determined by DFT. In addition, our results indicate that the activation energy barriers for hydrogen bulk diffusion are uniformly low ($ < 0.15 \ \mathrm{eV} $) for the calculation parameters probed here and that, in general, the effect of hydrogen tunneling is small at ambient temperatures. Our study provides a recipe to determine fundamental physical chemical properties of Ce-O-H interactions while also determining realistic ranges for diffusion kinetics. This can facilitate the determination of future coarse-grained models that will be able to guide and elucidate experimental efforts in this area. |
| title | Quantum Calculations of Hydrogen Absorption and Diffusivity in Bulk $\mathrm{CeO_2}$ |
| topic | Materials Science Computational Physics |
| url | https://arxiv.org/abs/2411.06536 |