Near-infrared photocatalytic activity induced by intrinsic defects in Bi₂MO₆(M = W, Mo)

Abstract

The electronic structure and related photocatalytic properties of Bi2MO6 (M = W, Mo) with various intrinsic defects are studied based on the first-principles density functional theory (DFT). Our results indicate that O vacancies form easily in both Bi2WO6 and Bi2MoO6 under Bi rich/O poor conditions. The near-infrared light transitions can be realized involving electrons from the O vacancy induced impurity states within the band gap to the conduction band. Rather than acting as photogenerated carrier recombination centers, the impurity states caused by O vacancies favor the transfer of photogenerated holes and further benefit the photocatalytic process due to the delocalized nature. The spatial separation of photogenerated carriers among different layers can be realized, which reduces the carrier recombination and improves the photocatalytic activity. In addition, Bi2WO6 with O vacancies is desirable for having better near-infrared photocatalytic performance than Bi2MoO6 due to the larger mobility of photogenerated holes.

Facile synthesis of Z-scheme graphitic-C3N4/Bi2MoO6 nanocomposite for enhanced visible photocatalytic properties

“…This illustrates the existence of g-C 3 N 4 in the 25%g-C 3 N 4 /Bi 2 MoO 6 composites. It could be seen that the absorption peak of 25%g-C 3 N 4 /Bi 2 MoO 6 at 668 cm -1 was ascribed to the Bi-O stretching mode [51]. The FT-IR and HRTEM results show that Bi 2 MoO 6 and g-C 3 N 4 have been coupled together successfully.…”

Tungsten-based nanomaterials (WO 3 & Bi 2 WO 6 ): Modifications related to charge carrier transfer mechanisms and photocatalytic applications

“…The oxygen vacancy induced impurity states are delocalized along (001) and (100) directions, but localized along the (010) plane, suggesting that the transfer of photogenerated holes is anisotropic. Due to the small effective mass and substantial dispersion of impurity states, the photogenerated holes can quickly transfer to the surface and enhance the reaction rates [243].…”

Generation of Oxygen Vacancy and OH Radicals: A Comparative Study of Bi2WO6 and Bi2WO6−x Nanoplates

“…Oxygenv acancy,a se lectron donor,c an also increase the electron density on the semiconductor photocatalyst. [15] The increased electrons can form ad onor level, narrow the energyg ap band, and extendt he absorption range. [16] Jing et al have calculated the impurity levelsi nB i 2 MO 6 (M = W, Mo) and the results revealed that the impurity states caused by oxygen vacancies favor the transfero fp hotogenerated holes and would furtherb enefit the photocatalytic process.…”