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Photoinduced Formation of Peroxide Ions on La 2 O 3 and Nd 2 O 3 under O 2 : Effects of Excitation Wavelength and Crystal Structure
Author(s) -
Jing XiaoLian,
She WenYu,
Li JianMei,
Chen QingChuan,
Weng WeiZheng,
An DongLi,
Wan HuiLin
Publication year - 2015
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201500312
Subject(s) - photoexcitation , ion , peroxide , excitation , analytical chemistry (journal) , chemistry , crystallography , microprobe , crystal structure , raman spectroscopy , materials science , photochemistry , mineralogy , optics , physics , organic chemistry , electrical engineering , engineering , chromatography
Photoinduced formation of peroxide ions on La 2 O 3 and Nd 2 O 3 under O 2 was studied by in‐situ microprobe Raman spectroscopy with attention focused on the effect of excitation wavelength and crystal structure on the O 2 2− formation. It was found that photoexcitations at 633, 532, 514, and 325 nm can induce O 2 2− formation over La 2 O 3 at 450 °C. By contrast, photoexcitation at 785 nm does not cause formation of O 2 2− up to 500 °C. Photoexcitation at 325 nm can induce O 2 2− formation on cubic Nd 2 O 3 at 25 °C, but cannot induce O 2 2− formation on hexagonal Nd 2 O 3 up to 200 °C. The significant difference in the behavior of O 2 2− formation over the Nd 2 O 3 samples of the two structures can be related to the difference in the capacity to adsorb O 2 . Since the number of oxygen vacancies in cubic Nd 2 O 3 is larger than that in the hexagonal one, the former has a higher capacity than the latter to adsorb O 2 . As a result, cubic Nd 2 O 3 is more favorable to the reaction of O 2 with O 2− to generate O 2 2− . The structural similarity between cubic Nd 2 O 3 and Nd 2 O 2 (O 2 ) may be another factor in favor of peroxide formation.