Structure and stability of CaH2 surfaces: on the possibility of electron-rich surfaces in metal hydrides for catalysis
Structure and stability of CaH2 surfaces: on the possibility of electron-rich surfaces in metal hydrides for catalysis
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CaH2表面的结构和稳定性：金属氢化物中富电子表面用于催化的可能性
DOI：
10.1039/c6ta09561e
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发表时间：
2017
影响因子：
--
通讯作者：
P. Sushko
中科院分区：
文献类型：
--
作者：
P. Ong;L. Johnson;H. Hosono;P. Sushko
使用从头计算模型研究了 (001)、(110) 和 (111) 晶体取向的 CaH2 表面的结构、热力学稳定性和电子性质。我们证明以氢原子平面终止的化学计量表面在能量上是最有利的，并讨论了这些表面上氢空位（VH）的性质。最稳定的原始表面的平均计算功函数（∼5.2 eV）与粉末样品的实验数据一致。中性氢空位容纳局域电子并在带隙中诱导缺陷态，从而将有效功函数转变为低得多的值~2.7 eV。预计表面 VH 会聚集成二聚体并形成富电子中心 (e−)Ca2+(e−)，在 800 K 以上稳定。这些结果表明，CaH2 的缺氢表面可以容纳大量的局部电子，从而产生新的催化功能，涉及表面、其上负载的催化剂和反应物质之间的电子转移。
Structure, thermodynamic stability, and electronic properties of CaH2 surfaces in (001), (110), and (111) crystallographic orientations are investigated using ab initio modeling. We show that stoichiometric surfaces terminated with a hydrogen atomic plane are the most energetically favorable and discuss properties of hydrogen vacancies (VH) at these surfaces. The average calculated work function of the most stable pristine surfaces (∼5.2 eV) is in agreement with experimental data for powder samples. Neutral hydrogen vacancies host localized electrons and induce defect states in the band gap, thereby shifting the effective work function to much lower values of ∼2.7 eV. Surface VH are predicted to aggregate into dimers and form electron-rich centers (e−)Ca2+(e−) stable to over 800 K. These results suggest that hydrogen-deficient surfaces of CaH2 can host a large concentration of localized electrons and, thus, give rise to new catalytic functionalities involving electron transfer between the surface, catalysts supported on it, and reacting species.
影响因子：
4
作者：
P. Sushko;A. Shluger;K. Hayashi;M. Hirano;H. Hosono
通讯作者：
P. Sushko;A. Shluger;K. Hayashi;M. Hirano;H. Hosono
影响因子：
3.3
作者：
Hayashi, K;Sushko, PV;Hosono, H
通讯作者：
Hosono, H
影响因子：
15
作者：
P. Sushko;A. Shluger;M. Hirano;H. Hosono
通讯作者：
P. Sushko;A. Shluger;M. Hirano;H. Hosono