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Infrared absorption on hydrogen in anatase TiO 2
Author(s) -
Lavrov E. V.
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201431814
Subject(s) - anatase , infrared spectroscopy , infrared , absorption (acoustics) , materials science , chemistry , photochemistry , optics , catalysis , organic chemistry , photocatalysis , physics , composite material
IR absorption study of natural single‐crystalline anatase TiO 2 has been performed. It was found that as‐received material reveals absorption lines at 3357.8, 3359.3, 3372.5, and 3389.3 cm −1 , whose intensity grows if the sample is hydrogenated from the H 2 ambient at 450 °C. In addition, hydrogenation results in the appearance of two lines at 3412.4 and 3416.9 cm −1 . Isotope substitution experiments have shown that all six lines are due to the stretch local vibrational modes (LVMs) of O–H bonds, which are preferentially aligned parallel to the c ‐axis of TiO 2 . The group of LVMs at 3357.8, 3359.3, 3372.5, and 3389.3 cm −1 retains the same relative intensities and is stable against thermal treatments up to 450 °C, whereas the hydrogen‐related complex(es) responsible for the 3412.4 and 3416.9 cm −1 lines disappear(s) after annealing at 250 °C. The nature of the defects resulting in these vibrational modes is discussed.