A novel Z-type heterojunction Bi3O4Cl/Bi4O5I2 photocatalytic composite with broad-spectrum antibacterial activity and degradation properties.

At present, the sustainable development of humans is facing health problems and ecological imbalance caused by environmental pollution. To solve the bacteria, antibiotics and other pollutants in wastewater, Bi3O4Cl and Bi4O5I2 with appropriate bandgap width were selected to prepare Z-type heterojunction Bi3O4Cl/Bi4O5I2 photocatalytic materials by calcination method. Under LED light, the best sample Bi3O4Cl/Bi4O5I2-4 could completely inactivate Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in 30 min, Bacillus subtilis (B. subtilis) and Pseudomonas aeruginosa (P. aeruginosa) in 20 min, and degrade 70.6% of tetracycline (TC) and 97.4% of Rhodamine B (RhB). Photocurrent and electrochemical impedance tests (EIS) confirmed the high photocurrent response and low charge transfer resistance in the Bi3O4Cl/Bi4O5I2. The photocatalytic antibacterial and degradation mechanism of Z-type Bi3O4Cl/Bi4O5I2 heterojunction was verified by capture experiments. Thus, this study provides a compact and efficient photocatalyst with broad-spectrum antibacterial activity and degradation properties.

Construction of a novel double S-scheme structure WO3/g-C3N4/BiOI: Enhanced photocatalytic performance for antibacterial activity.

In recent years, the threat to human health from bacteria in wastewater has attracted attention, and photocatalytic technology has emerged as a promising strategy for inactivating bacteria in water. Therefore, it is of great research value to develop a novel high-efficiency photocatalytic system with the visible light response. We successfully designed a double S-scheme heterojunction composite WO3/g-C3N4/BiOI (WCB) in this paper. The preparation of WCB composites was demonstrated by a series of characterizations, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The antibacterial effects of photocatalysts against representative Gram-negative strain Escherichia coli (E. coli) and Gram-positive strain Staphylococcus aureus (S. aureus) were tested under LED light irradiation. The novel photocatalyst presented excellent antibacterial properties, inactivating E. coli in 12 min and S. aureus in 20 min. The bacterial cell inactivation process was studied by scanning electron microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Active species capture experiments show that the active species present in the WCB composites in the process of inactivating bacteria are h+, e-, OH and O2-. In conclusion, the synthesized double S-scheme WCB photocatalyst exhibits remarkable photocatalytic antibacterial activity under LED light and has broad prospects for practical application in water antibacterial treatment.

Fabrication of n-p ß-Bi2O3@BiOI core/shell photocatalytic heterostructure for the removal of bacteria and bisphenol A under LED light.

A novel n-p ß-Bi2O3@BiOI core/shell heterostructure was successfully constructed by a facile ultrasonication method. SEM, TEM, XRD and XPS confirmed the core/shell structure. UV-vis indicated the composite had good absorption of visible light. Photocurrent and electrochemical impedance analysis (EIS) revealed effective electron (e-) and hole (h+) separation efficiency in the core/shell hybrid structure, which induced a significantly improved photocatalytic activity. The ß-Bi2O3@BiOI photocatalyst effectively treated with Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and bisphenol A (BPA) under LED light, and presented better photocatalytic antibacterial performance than ß-Bi2O3 and BiOI. Trapping experiment revealed that h+ played an important role in photocatalytic reaction. The present work provided a novel LED light-activated photocatalyst that was efficient for antibacterial application.

Facile synthesis CQDs/SnO2-x/BiOI heterojunction photocatalyst to effectively degrade pollutants and antibacterial under LED light.

To remove multitudinous pollutants from wastewater, the design of a highly efficient and multifunctional photocatalyst is necessary. A novel CQDs/SnO2-x/BiOI photocatalyst (named CSnBI composite) was prepared by combining carbon quantum dots (CQDs), large specific surface area SnO2-x nanocrystals and BiOI nanocrystals to obtain a compact hybrid structure. TEM and Raman techniques confirmed the structure of CSnBI composite. The photocurrent and EIS showed that the photoexcited electron-hole pairs separation efficiency was improved. As anticipated, novel CSnBI photocatalyst can successfully remove tetracycline, methyl orange, E. coli (Escherichia coli) and S. aureus under a LED light due to the hybridization contaction among CQDs, SnO2-x and BiOI. The mechanism showed that the introduction of CQDs promoted visible light absorption and efficient separation of photogenerated carriers of SnO2-x/BiOI heterojunction. The capture experiment and related measurements showed that h+, •O2- and •OH are active species in the photocatalytic process. This study gave a novel case for facile construction of photocatalysts with tight hybrid structure.

Facile synthesizing Z-scheme Bi12O15Cl6/InVO4 heterojunction to effectively degrade pollutants and antibacterial under light-emitting diode light.

The design of a photocatalytic system with Z-scheme heterojunction is the key to charge separation. In this paper, a simple synthesis method was used to prepare Bi12O15Cl6/InVO4 photocatalyst. The synthesized photocatalyst can effectively degrade pollutants, and inactivate bacteria under LED light irradiation. The optimal ratio of 30% Bi12O15Cl6/InVO4 material effectively degraded 78.85% of TC and 97.83% of RhB within 90 min and inactivated Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in 40 min. This improvement in photocatalytic performance is mainly due to the formation of a Z-scheme heterojunction between Bi12O15Cl6 and InVO4, which produces effective charge separation and improves photocatalytic degradation and antibacterial activity. The capture experiment revealed the main active substances. The effects of catalyst dosage and pollutant concentration were investigated in details. The intermediates of TC degradation were identified by mass spectrometry (MS), and the possible photocatalytic degradation pathway was proposed. Capture experiment and related measurements proposed the Z-scheme mechanism. This work emphasizes the importance of heterogeneous structure construction and proposes feasible solutions for the rational design of catalysts with photodegradation and antibacterial properties under LED light.

Constructing an S-scheme CuBi2O4/Bi4O5I2 heterojunction for lightemittingdiode-driven pollutant degradation and bacterial inactivation.

The CuBi2O4/Bi4O5I2 S-scheme heterojunction structure was constructed by a hydrothermal and subsequent calcination route. The combination of CuBi2O4 and Bi4O5I2 produced excellent photocatalytic performance under an LED light. A series of technical characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), were used to determine the successful construction of S-scheme CuBi2O4/Bi4O5I2 composites. The improvement of photogenerated carrier separation efficiency helped to achieve the best photocatalytic performance of 37% CuBi2O4/Bi4O5I2, which can degrade tetracycline (TC) to 81.67% in 90 min, and completely inactivate Escherichia coli (E. coli) in 20 min and Staphylococcus aureus (S. aureus) in 40 min. The effects of some key parameters (such as the concentration of pollutants, the amount of catalyst, pH value of a solution, various inorganic anions and various water substrates) and the possible degradation path of tetracycline were systematically studied. Finally, the removal of pollutants and inactivation of bacterial mechanisms based on the S-scheme heterojunction (CuBi2O4/Bi4O5I2) was proposed. This study provides insight into the synthesis of S-scheme heterojunction photocatalysts, which can efficiently degrade organic pollutants and inactivate bacteria under LED light irradiation.