Enhanced Molecular Oxygen Activation on (001) Facets of Zn‐Doped BiOCl Nanosheets for Ciprofloxacin Degradation

Abstract

The crucial oxidant in photocatalytic degradation of antibiotics is the photogenerated reactive oxygen species (ROS) but many photocatalytic processes suffer from low ROS generation efficiency. In this work, a Zn doping strategy is used to improve the photocatalytic oxygen activation ability of bismuth oxychloride (BiOCl) nanosheets with exposed (001) facets. Introduction of Zn into BiOCl can narrow the bandgap to extend photoresponse to visible region. Meanwhile, the separation of photoinduced charge carriers can also be promoted by increasing the valence band width of BiOCl. Furthermore, the adsorption and activation of oxygen molecules on the (001) surface are greatly enhanced by introducing more oxygen vacancies. Thus, the Zn‐BiOCl nanosheets have an excellent activity for the degradation of ciprofloxacin (CIP) under visible light by activating oxygen into superoxide radicals. The optimal ratio of Zn doping is 8% and the degradation rate is 2.6 times higher than that of BiOCl. The photocatalytic oxidation of CIP follows a pseudo‐first‐order kinetics. The removal efficiency of CIP reaches 98% in 80 min. Finally, the complete pathway of the CIP photocatalytic oxidation is unraveled by high performance liquid chromatography‐mass spectrometry. This study provides an advanced solution to promote the performance of photocatalyst to degrade organic pollutants in water.

Bismuth Vacancy-Induced Efficient CO2 Photoreduction in BiOCl Directly from Natural Air: A Progressive Step toward Photosynthesis in Nature

“…The Raman spectra of VBOC and BOC (Figure 2a) show that the strong band at 144.9 cm −1 and the weak band at 201.1 cm −1 correspond to the A 1g and E g internal Bi−Cl stretching modes, 14 respectively, while E g external Bi−Cl stretching is supposed to be obscured at 142 cm −1 by A 1g . 15,16 The new bands near 100 cm −1 can be assigned to first-order vibrational modes E g and A 1g of Bi metal, 17 confirming the existence of V Bi in VBOC. The FTIR spectra reveal the distinct blue shifts of the Bi−O and Bi−Cl bands in VBOC compared to those in BOC, which indicates that the more unstable groups requiring lower energies for vibrations probably resulted from the valid introduction of V Bi into VBOC (Figure 2b).…”

Microscopic Nature of Gas Adsorption on WO3 Surfaces: Electron Interaction and Localization

“…In order to better understand the surface chemistry of WO 3 (001), we use X-ray photoelectron spectroscopy (XPS) to track the electronic structure changes of WO 3 nanosheets (Figure S6). According to the study of Dongyu Xu et al, we can know that the binding energy of oxygen vacancies is greater than the binding energy of lattice oxygen. For an electron of a certain energy level, its electron binding energy is determined by the Coulomb force between it and the nucleus and the screening effect of other electrons .…”

Engineering of Band Structure of Bismuth Selenide Ultrathin Nanosheets as Multifunctional Material for Photocatalytic Application

“…Possible reason is that HCO 3 − , SO 4 2− and Cl − trapped partial e − and h + to generate the corresponding active radical (·HCO 3 ,·SO 4 − and ·Cl) that have low activity, thus affect degradation rate. [ 43 ] Whereas, PO 4 3− has greater inhibitory effect on photocatalytic activity and the CIP degradation rate is only about 45%, i.e., reduced by 43.7% (Figure S9d, Supporting Information), which is attributed to that more charge can capture e − and h + to generate H 2 PO 4 − and HPO 4 2− , in contrast, active oxygen radicals decrease. Both of them lead to low degradation.…”