Promoted Electron Transfer along the Newly Formed Bi–O–S Bond in Bi₂O(OH)₂SO₄

Abstract

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.

Enhanced plasmonic photocatalysis by SiO 2 @Bi microspheres with hot-electron transportation channels via Bi–O–Si linkages

“…Benefiting from SPR, the photogenerated electrons in metallic Bi are rapidly transferred to the surface of SiO2 via the Bi-O-Si bonds, which serve as hot-electron transportation channels. This promotes the separation and transfer of the photoexcited carriers, as well as the formation of reactive radicals for oxidation [30]. The prolonged lifetime of the charge carriers increases their probability of participating in photocatalytic reactions before recombination.…”

“…The ability of SiO2@Bi and elemental Bi to remove NO under photocatalytic conditions can be ascribed to the direct plasmonic photocatalytic effect of the semimetal Bi [14,[39][40][41]. The greatly enhanced activity of SiO2@Bi can be attributed both to the enlarged surface areas and to the increased production of active species, benefiting from the presence of polar Bi-O-Si bonds [30]. It is noteworthy that the photocatalytic activity of SiO2@Bi under UV light irradiation actually increases slightly after five cycles (Fig.…”