Today, research is increasingly focused on surface control of semiconductors; however, very little is known about the effect of bulk chemical bonds on photoelectrochemistry properties. In this report, Bi2O(OH)2SO4 with and without specific Bi-O-S bonds (WB and WOB) is synthesized via hydrothermal and water bath methods, respectively, and we reveal the Bi-O-S bond-dependent photoelectrochemistry properties. Both WB and WOB belong to a monoclinic space group (P21/c), but the newly synthesized WB has different unit cell parameters of a = 8.062 Å, b = 8.384 Å, and c = 5.881 Å, compared with WOB (a = 7.692(3) Å, b = 13.87(1) Å, c = 5.688(2) Å). Compared with WOB (4.18 eV), WB has a narrower band gap (3.6 eV), higher electrical conductivity, and an increased charge separation efficiency. It is found that the electrons are easy to transfer along the newly formed Bi-O-S bond in bulk; thus, the Bi-O-S bonds in WB have efficiently improved the photoelectrochemistry properties. As a result, WB exhibits a 1.1 times higher photocatalytic activity than WOB for the degradation of RhB under ultraviolet light irradiation (<420 nm). This helps us to understand the photoelectrochemistry properties from crystal bulk, but not merely from the crystal surface; thus, this study provides a new idea for improved photoelectrochemistry properties of semiconductors.

Herein, we, for the first time, have developed a facile anion intercalation method to prepare uniform Bi2O2[BO2(OH)]/Bi2O3 and Bi2O2[BO2(OH)] nanosheets, in which H2O2 is employed as the exfoliating reagent to break the weak Bi−O bonds (2.572 Å) between [Bi2O2]n2n+ layers, then allowing borate ion to precisely intercalate into [Bi2O2]n2n+ layers. Further, density functional theory (DFT) calculations reveal that both O 2p and B 2p of [BO3]3− layer obviously contribute to an downshift of valence band (VB) and upshift of conduction band (CB), leading to a wider band gap of Bi2O2[BO2(OH)]. Thus, Bi2O2[BO2(OH)]/Bi2O3 exhibit a higher photocatalytic activity than Bi2O3 for the degradations of rhodamine B (RhB) under ultraviolet light irradiation (λ < 420 nm), which may be resultant from a synergetic effect of double internal electronic field that has improved charge separation efficiency. For featured layered materials, anion intercalation is an artful facile strategy to develop new, efficient photocatalysts.