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Photophysical and Photocatalytic Properties of Ag 2 M 2 O 7 (M=Mo, W)
Author(s) -
Kim Dong Wook,
Cho InSun,
Lee Sangwook,
Bae ShinTae,
Shin Seong Sik,
Han Gill Sang,
Jung Hyun Suk,
Hong Kug Sun
Publication year - 2010
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.03972.x
Subject(s) - photocatalysis , band gap , triclinic crystal system , rhodamine b , direct and indirect band gaps , materials science , electron affinity (data page) , analytical chemistry (journal) , crystallography , chemistry , crystal structure , catalysis , optoelectronics , molecule , biochemistry , organic chemistry , chromatography
Ag‐based oxides, Ag 2 M 2 O 7 (M=Mo, W) with a triclinic structure, were prepared using a conventional solid‐state reaction method, and their band structures and photocatalytic properties were investigated. From the electronic band structure calculations, Ag 2 Mo 2 O 7 had an indirect band gap of 2.65 eV, whereas Ag 2 W 2 O 7 had a direct band gap of 3.18 eV. Moreover, the calculated electron affinities were 4.75 eV for Ag 2 Mo 2 O 7 and 4.62 eV for Ag 2 W 2 O 7 . The smaller band gap and higher electron affinity of Ag 2 Mo 2 O 7 than those of Ag 2 W 2 O 7 originated from the contribution of the unoccupied Mo 4 d orbital to the conduction band, which was positioned at a lower energy level than the W 5 d orbital. The effects of the different band structure characteristics in Ag 2 M 2 O 7 (M=Mo, W) on the photocatalytic activity were investigated by the degradation of a Rhodamine B dye solution under visible light irradiation. The results showed that the photocatalytic activity of Ag 2 Mo 2 O 7 was much higher than that of Ag 2 W 2 O 7 and comparable with a well‐known WO 3 powder. The higher photocatalytic property of Ag 2 Mo 2 O 7 was attributed to its higher optical absorption ability and lower charge recombination rate.