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Hydrogen Isotope Absorption in Unary Oxides and Nitrides with Anion Vacancies and Substitution
Author(s) -
Watanabe Takumi,
Kunisada Yuji,
Sakaguchi Norihito
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201801091
Subject(s) - nitride , hydrogen isotope , ion , substitution (logic) , hydrogen , inorganic chemistry , absorption (acoustics) , chemistry , materials science , crystallography , organic chemistry , layer (electronics) , computer science , composite material , programming language
The absorption states of hydrogen isotopes in various ceramic materials were investigated by density functional theory. For pristine ceramic materials, main‐group oxides do not form any bond with a hydrogen atom. However, transition metal oxides form hydroxyl groups and absorb hydrogen atoms. Main‐group and transition metal nitrides form ionic bonds between a hydrogen atom and the surrounded cation. For anion‐deficient ceramic materials, hydrogen atoms are negatively charged because of excess electrons induced by anion vacancies, and ionic bonds form with the surrounded cation, which stabilizes the hydrogen absorption state. N substitutional doping into oxides introduces an electron hole, while O substitutional doping into the nitrides introduces an excess of electrons. Therefore, hydrogen isotopes form covalent bonds in N‐substituted oxides, and form hydride ions in O‐substituted nitrides. Thus, Al 2 O 3 , SiO 2 , CrN, and TiN are promising materials as hydrogen permeation barriers.