Inorganic photocatalysts have been regarded as a promising candidate in the domain of tumor photodynamic therapy (PDT) due to their inspirational photocatalytic activity. In this study, a Bi
4
O
5
Br
...2
photocatalyst was synthesized and it exhibited effective photo-killing activity of A549 cells (a human lung carcinoma epithelial cell line) in vitro. On this basis, we modified Bi
4
O
5
Br
2
with carbon quantum dots (CQDs) via a hydrolysis method at room temperature, which resulted in an improved photo-killing effect of Bi
4
O
5
Br
2
to A549 cells. The samples and the interaction between samples and cells were fully characterized. It has been found that the loading of CQDs on Bi
4
O
5
Br
2
can reduce the hydration ratio, increase the cellular uptake and improve the photogenerated reactive oxygen species (ROS) as compared with pristine Bi
4
O
5
Br
2
. Electron spin resonance (ESR) analysis and radical-trapping experiments manifested that the ROS contributed to PDT may be ·O
2
−
and ·OH. This study may provide a useful strategy to ameliorate the penetrability, cell compatibility and PDT effect upon cancer cells of other inorganic photocatalysts.
Graphic abstract
The BiOCl powders prepared by the hydrolysis method were investigated with the X-ray diffractometry (XRD), scanning electron microscopy (SEM) and differential thermal analysis (TG-DTA). The results ...show that the powders are of the tetragonal primitive crystal structure, composed of homogeneous particles of fine ferrite plates, and stable in the temperature range of 40-600 °C. In addition, the photocatalytic activity of BiOCl powders was evaluated by methyl orange (MO) in aqueous solution illuminated by xenon-lamp, and the effect of the BiOCl amount on the photocatalytic activity was investigated. Moreover, the photocatalytic properties of BiOCl and TiO
2-P25 were also compared. The results show that the favorite amount of BiOCl powders is 1.0 g/L for the MO degradationand the photocatalytic activity of the BiOCl catalyst is comparable to the TiO
2-P25 catalyst under the same experiment condition.
The powders of ilmenite structure NiTiO3 were prepared by a modified Pechini process using tetrabutyl titanate and nickel acetate as raw materials, and using citric acid and ethanol as a chelating ...agent and a solvent respectively. The powder samples were characterized by thermogravimetric and differential thermal analysis （TG-DTA） and X-ray diffraction （XRD）. The photocatalytic activity of NiTiO3 under the irradiation of ultraviolet rays （UV） light was evaluated by degrading hurnic acid （HA） in water as a probe reaction. The possible photodegra- dation mechanism was studied by the examination of active species .OH, .O2, and holes （h＋） through adding scavengers. The TG-DTA and XRD results indicated that the good crystal structure of ilmenite phase NiTiO3 could be obtained when the Ni-Ti citrate complex was cal- cined at 600℃. The photocatalytic activity experiments indicated that NiTiO3 had favourable photocatalytic activity under the irradiation of UV light, and the photocatalytic degradation rate of HA reached 95.3% after a 2.5 h reaction with the photocatalyst calcined at 600℃ and a photocatalyst dosage of 0.4 g/L. The possible photocatalytic mechanism was deduced that holes （h＋） and .OH radicals are the major reactive active species in the photocatalytic reaction, and dissolved oxygen plays a weak role in the degradation of HA.
Metal–organic frameworks (MOFs) are important functional materials. MOF-5 (IL) (Zn4O(BDC)3 (BDC=1,4-benzene- dicarboxylate) was in situ synthesized by the electrochemical method using a tunable ionic ...liquid (IL), 1-butyl-3-methylimidazolium chloride, as template. The crystallization of distinctly spherical MOF-5 (IL) synthsized in ionic liquid by the electrochemical method is attributed to π–π stacking effect, ionic bond, and coordination bond. The analysis results show that the product MOF-5(IL) exhibits better crystallinity and higher thermal stability than MOF-5 generated using the solvothermal method. The cyclic voltammetry reveals that the electrosynthesis reaction is irreversible and controlled by the diffusion. The experiments on methylorange degradation show that the unique structure characteristics of MOF-5(IL) can enhance the photocatalytic ability of BiOBr. Therefore, MOFs can replace noble metals to improve the photocatalytic properties of bismuth oxyhalide.
A novel photocatalyst, bismuth oxychloride (BiOCl) micro-nano particles with a fine ferrite plate structure, was prepared by a low-cost, simple hydrolytic method. The as-prepared BiOCl was ...characterized by scanning electron microscopy (SEM), thermogravimetric analysis-differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectra (DRS). The effects of preparation conditions such as sodium dodecyl benzene sulfonate (SDBS) dispersant, HCl concentration, and heat treatment temperature on BiOCl performances were investigated. Moreover, its photocatalytic activity was evaluated on the degradation of methylene orange (MO) and was compared with that of TiO
2
(P25). The experimental results confirmed that BiOCl micro-nano particles prepared with SDBS, the HCl concentration of 1.5 mol/L, and the heat treatment temperature of 80°C exhibited the best performance for the photodegradation of MO solution, and they showed good stability and better photocatalytic activity than P25 photocatalyst.
A series of BiOX (X=Cl, Br) were prepared by simple hydrolysis and then calcined at various temperatures and they were characterized by XRD, Raman, SEM, DSC–TGA, BET and UV–Vis. The photocatalytic ...activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under simulated solar light irradiation. The results show that the phase structure, crystallite size, morphology, specific surface area, porous structure, and the absorption band-edges are related to the calcination temperature. For BiOBr, it has completely transformed to Bi24O31Br10 at 600 °C and begins to transform to Bi2O3 at 800 °C. As for BiOCl, it begins to transform to Bi24O31Cl10 at 600 °C and completely transforms to Bi24O31Cl10 at 800 °C. Finally, the photocatalytic activity of BiOCl decreases with the temperature increasing owing to decrease of the specific surface areas and pore size, while the photocatalytic activity of BiOBr increases in the first stage and then decreases, which is related to good crystallization and three-dimensional structure.
In order to simultaneously solve the problems of the poor light absorption capacity and high recombination rate of photogenerated carriers, Bi5O7Br photocatalyst with abundant ordered/disordered ...structures (O/D-Bi5O7Br) was prepared through a simple in situ disorder engineering. The prepared samples were characterized by XRD, TEM, HRTEM, SAED, XPS, UV-Vis diffuse reflectance spectra (DRS), and the activity was evaluated by photocatalytic degradation of tetracycline hydrochloride (TC) and hydrogen evolution under visible light irradiation. Results revealed that the ordered/disordered structure not only enhances the light absorption ability, uplifts conduction band position, facilitates the transfer and separation of photogenerated carriers, but also offers abundant unsaturated atoms as active sites for the photocatalytic process. Therefore, O/D-Bi5O7Br exhibits a high hydrogen evolution rate of 38.12 μmol/(g·h) and superior TC degradation rate of 86% within 135 min.
TG1; Two types of Sb-doped SnO2 films on titanium substrate were prepared by the combination of electro-deposition and dip-coating (Ti/SnO2-Sb2O4/SnO2-Sb2O4) and single dip-coating (Ti/SnO2-Sb2O4), ...respectively. The surface morphology and crystalline structure of both film electrodes were characterized using X-ray diffractometry(XRD) and scanning electron microscopy(SEM). XRD spectra indicate that the rutile SnO2 forms in two films and a TiO2 crystallite exists only in Ti/SnO2-Sb2O4 electrode. SEM images show that the surface morphology of two films is typically cracked-mud structure. The photooxidation experiment was proceeded to further confirm the two electrode activity. The results show that the photoelectrocatalytic degradation efficiency of Ti/SnO2-Sb2O4 electrode with sub-layer is higher than that of simple Ti/SnO2-Sb2O4 electrode using phenol as a model organic pollutant. The Ti/SnO2-Sb2O4/SnO2-Sb2O4 photoanode has a better photoelectrochemical performance than Ti/SnO2-Sb2O4 photoanode for the removal of organic pollutants from water.
A series of zinc titanate nanoparticles was successfully synthesized using a simple sol–gel technique. The composites were characterized by thermogravimetric and differential thermal analysis ...(TG-DTA), X-ray diffraction (XRD) patterns, scanning electron microscope (SEM), X-ray photoelectron spectra (XPS) and UV–vis diffuse reflectance spectra (UV–vis). The photocatalytic activity of samples was investigated by degradation of humic acid (HA) in water under xenon lamp. The sample calcined at 800°C was found to exhibit much higher photocatalytic activity than the other samples. The investigation of photocatalytic mechanism indicates that the holes (h+) and OH radicals may be the major reactive species for the degradation of HA. Meanwhile, the processing parameters such as the light source and the dosage of catalysts play an important role in tuning the photocatalytic activity. The enhancement of photocatalytic activity for the zinc titanate nanoparticles calcined at 800°C may be attributed to the higher redox ability, coordination of Ti ions and smaller particle size.
