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Hydrogen Donors in Anatase TiO 2
Author(s) -
Lavrov Eduard V.,
Chaplygin Igor,
Herklotz Frank,
Melnikov Vladlen V.
Publication year - 2021
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202100171
Subject(s) - anatase , density functional theory , infrared spectroscopy , hydrogen , spectroscopy , absorption spectroscopy , chemistry , molecular vibration , ab initio , infrared , absorption (acoustics) , phonon , hydrogen bond , ab initio quantum chemistry methods , materials science , chemical physics , atomic physics , molecular physics , computational chemistry , molecule , condensed matter physics , optics , physics , organic chemistry , catalysis , photocatalysis , quantum mechanics , composite material
Two hydrogen‐related donors in anataseTiO 2 —interstitial hydrogen ( H i ) and hydrogen substituting for oxygen ( H O )—are addressed by means of ab initio density functional theory and vibrational mode spectroscopy. First‐principles calculations and infrared (IR) absorption measurements reveal thatH iforms an OH bond lying in the basal plane of the crystal characterized by a stretch local vibrational mode (LVM) with a frequency of 3412 cm − 1. According to the calculations, the vibrational spectrum of the threefold‐coordinated hydrogen inH Oincludes two stretch LVMs with the frequencies of 1014 and 1294 cm − 1. The theoretically predicted modes occur within the strong two‐phonon absorption band ofTiO 2 , so the conclusions of theory cannot be verified by conventional IR absorption spectroscopy. In accordance with experimental findings,H iis shown to be unstable at room temperature, whereby formation of interstitialH 2should be a preferential sink for hydrogen in defect‐free anatase. It is also found that ofH 2 ,H i , andH O , the latter is the most energetically favorable defect, which may account for the “hidden” hydrogen unavailable for the standard spectroscopic techniques.