Synthesis of one-dimensional hierarchical Bi2O3 with enhanced photocatalytic reduction of Cr(VI) and degradation of organic compounds under simulated sunlight

Generation of •OH and •O2– Radicals by a Bi2O3-Nanoparticle/Bi4O5Br2 Type-II Heterojunction for Photocatalytic Degradation of Organic Molecules

“…For an indirectly allowed transition, the value of n is 4, while for a directly allowed transition, the value of n is 1. The n values for both Bi 4 O 5 Br 2 and Bi 2 O 3 are 4, , i.e., Bi 4 O 5 Br 2 and Bi 2 O 3 are all indirect band-gap semiconductors. The determined E g values of as-prepared Bi 4 O 5 Br 2 and Bi 2 O 3 are ∼2.39 and 2.58 eV, respectively (Figure b), close to reported results. , …”

“…The n values for both Bi 4 O 5 Br 2 and Bi 2 O 3 are 4, 12,36 i.e., Bi 4 O 5 Br 2 and Bi 2 O 3 are all indirect band-gap semiconductors.…”

“…Bismuth oxide (Bi 2 O 3 ) is a typical lamellar semiconductor, with an E g of 2.58–2.85 eV and especially a deep VB potential, which is advantageous for photocatalytic reactions to produce holes (h + ) with a strong oxidation capacity . It has been used for CO 2 reduction, water splitting, contaminant degradation, lignin degradation, nitrogen fixation, and preparation of heterogeneous photocatalysts with other compounds to improve photoactivity, such as CdMoO 4 , TiO 2 , SrTiO 3 , Zn 3 In 2 S 6 , ZnO, MnO 2 , and Ta 2 O 5 , but has not been used to modify Bi 4 O 5 Br 2 . So it makes sense to synthesize a heterojunction photocatalyst composed of Bi 4 O 5 Br 2 with a high CB potential and Bi 2 O 3 with a low VB potential. , …”

“…Additionally, the value of n is a constant that relies on the semiconductor's transition characteristics. For an indirectly allowed transition, the value of n is 4, while for a directly allowed transition, the value of n is 1.The n values for both Bi 4 O 5 Br 2 and Bi 2 O 3 are 4,12,36 i.e., Bi 4 O 5 Br 2 and Bi 2 O 3 are all indirect band-gap semiconductors.The determined E g values of as-prepared Bi 4 O 5 Br 2 and Bi 2 O 3 are ∼2.39 and 2.58 eV, respectively (Figure9b), close to reported results 29,35. To determine the energy band levels of the samples, UPS spectra of Bi 4 O 5 Br 2 and Bi 2 O 3 were measured.…”