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Effects of the crystalline structure of Ga 2 O 3 on the photocatalytic activity for CO production from CO 2
Author(s) -
Kawaguchi Yu,
Yamamoto Muneaki,
Ozawa Akiyo,
Kato Yuma,
Yoshida Tomoko
Publication year - 2019
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6552
Subject(s) - photocatalysis , calcination , gallium , x ray photoelectron spectroscopy , denticity , nitrate , nuclear chemistry , carbonate , materials science , chemistry , inorganic chemistry , crystallography , catalysis , crystal structure , chemical engineering , metallurgy , organic chemistry , engineering
Ga 2 O 3 samples with different crystalline structures were prepared by calcination of a gallium nitrate powder around 800 K. Ga 2 O 3 samples with mixed phases of γ and β showed high photocatalytic activity for CO production from CO 2 reduction with water, and the activity was even higher than that for an Ag‐loaded β‐Ga 2 O 3. The photocatalytic activity increased with time. The increase was attributed to the appearance of GaOOH resulting from the interaction of Ga 2 O 3 with water during the reaction as revealed by XRD and XPS analyses. In situ FT‐IR measurements revealed that bicarbonates and bidentate carbonate species were adsorbed on GaOOH. Therefore, the increase of the photocatalytic activity with time would be derived from the formation of GaOOH phase on the γ‐Ga 2 O 3 and β‐Ga 2 O 3 sample.