Optical and Photocatalytic Properties of Br-Doped BiOCl Nanosheets with Rich Oxygen Vacancies and Dominating {001} Facets

Abstract

Crystal facet engineering and nonmetal doping are regarded as effective strategies for improving the separation of charge carriers and photocatalytic activity of semiconductor photocatalysts. In this paper, we developed a facial method for fabricating oxygen-deficient Br-doped BiOCl nanosheets with dominating {001} facets through a traditional hydrothermal reaction and explored the impact of the Br doping and specific facets on carrier separation and photocatalytic performance. The morphologies, structures, and optical and photocatalytic properties of the obtained products were characterized systematically. The BiOCl samples prepared by the hydrothermal reaction exhibited square-like shapes with dominating {001} facets. Photodeposition results indicated that photoinduced electrons preferred to transfer to {001} facets because of the strong internal static electric fields in BiOCl nanosheets with dominating {001} facets. Br doping not only contributed to the formation of impurity energy levels that could promote light absorption but introduced a large number of surface oxygen vacancies (VO) in BiOCl photocatalysts, which was beneficial for photocatalytic performance. Moreover, the photocatalytic activities of these products under visible light were tested by degradation of rhodamine B (RhB). Because of the synergistic effect of the dominating {001} facets, Br doping, and rich VO, oxygen-deficient Br-doped BiOCl nanosheets exhibited improved carrier separation, visible light absorption, and photocatalytic efficiency.

A Comprehensive Review on the Boosted Effects of Anion Vacancy in the Heterogeneous Photocatalytic Degradation, Part II: Focus on Oxygen Vacancy

“…Both effects are beneficial for enhancing photocatalytic activity. 198 In an N-doped TiO 2 anatase matrix, the formation of localized states in the band gap has been confirmed by DFT calculations. Substitutional N states lie just above the VB, while interstitial N states lie higher in the gap.…”

“…These energy levels enhance light absorption. Both effects are beneficial for enhancing photocatalytic activity …”

Effect of tin doping and tin-bromine co-doping on electronic and optical properties of BiOCl crystal: density functional theory

“…Various compounds belonging to the family of bismuth-based photocatalysts, including Bi 2 O 3 [12], Bi 2 S 3 [13], Bi 2 WO 6 [14], Bi 2 MoO 6 [15], BiPO 4 [16], BiOX [17], BiVO 4 [18], Bi 3 NbO 7 [19], Bi 3 TiNbO 9 [20], Bi 4 NbO 8 Cl [21], among others, have exhibited remarkable photocatalytic efficacy when exposed to visible light [22]. BiOCl, a member of the BiOX family, has garnered significant research interest in the realms of energy and environmental cleanup [23][24][25]. Being a wide-band-gap semiconductor, BiOCl exhibits experimental band gaps varying from 3.17 to 3.54 eV [26] at room temperature, restricting its light absorption to the ultraviolet region solely [27].…”