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TiO2 nanospheres/AgVO3 quantum dots composite was synthesized by a facile in situ ultrasonic reaction route and systematically characterized by XRD, XPS, FESEM, TEM, UV–DRS and PL. The results demonstrated that AgVO3 QDs were successfully anchored on the surface of TiO2 nanospheres. The TiO2/AgVO3 composite displayed a high and stable visible light photocatalytic inactivation activity toward E. coli, which mainly derived from the synergetic effect between TiO2 and AgVO3, including a good distribution of AgVO3 QDs on the surface of TiO2 nanospheres, increased visible light harvesting and improved separation efficiency of photoinduced electron-hole pairs. Our study revealed that TiO2/AgVO3 composite could be a promising candidate photocatalyst for treating microbial-contaminated water.

g-C3N4/Cu2O composites were successfully synthesized by a facile chemical precipitation method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and UV diffuse reflectance spectroscopy (UV-DRS) techniques were employed to characterize the as-synthesized photocatalysts. The photocatalytic experiments indicated that the g-C3N4/Cu2O composites displayed higher photodegradation activity of tetracycline (TC) and inactivation efficiencies of Escherichia coli (E. coli) as well as Fusarium graminearum (F. graminearum) in comparsion with bare g-C3N4 and Cu2O under visible light irradiation. Photoluminescence (PL) spectra implied that the heterojunction between g-C3N4 and Cu2O could efficiently promote the separation efficiency of photo-induced charge carriers. Active species trapping experiment and electron spin resonance (ESR) analysis revealed that O2−, OH and h+ played important roles in the photocatalytic process. This study could provide new insights into the design of multifunctional g-C3N4-based photocatalysts for environmental purification.

Photodisinfection by semiconductors has been proven to be an effective method for achieving antibacterial or antifungal activity. However, the toxicity of the nanomaterial to the environment and organisms is a major concern. Herein, a highly efficient and environmentally friendly photodisinfection material of a carbon dots (CDs) decorated Na2W4O13 composite with WO3 photocatalyst was fabricated via a facile hydrothermal-calcination approach. The TEM (transmission electron microscopy) images showed that CDs decorated the surface of the Na2W4O13 flakes. Compared with the samples without incorporated CDs, the as-synthesized composite of CDs/Na2W4O13/WO3 exhibited excellent antimicrobial activity against E. coli under visible light illumination. Electron spin resonance (ESR) spectroscopy and reactive species scavenging experiments revealed that the hydroxyl radicals and superoxide radical anions played the most important role in the photocatalytic bacterial inactivation. Furthermore, the cytotoxicity of the CDs/Na2W4O13/WO3 composite was evaluated by analyzing the viability of HepG2 and Chinese hamster lung (V79) cells using Cell Counting Kit-8 (CCK-8).

g-C3N4/NH2-MIL-101(Fe) composites are successfully fabricated by a facile in situ solvothermal method. The as-prepared samples have been characterized by XRD, FTIR, XPS, FESEM, TEM, DRS and PL analysis. Under visible light irradiation, the g-C3N4/NH2-MIL-101(Fe) composite shows higher photocatalytic activities than bare g-C3N4 and NH2-MIL-101(Fe) for Cr(VI) reduction and MO degradation. The improved photocatalytic performances are ascribed to the efficient charge separation and transfer on the interface between g-C3N4 and NH2-MIL-101(Fe). Control experiments show that the pH value is vital for Cr(VI) reduction, and meanwhile, the addition of hole scavengers promotes the photocatalytic reduction significantly. Finally, a possible reaction mechanism had also been investigated in detail.

Visible-light-driven g-C3N4/BiOI/BiOBr composite photocatalysts were successfully synthesized by a facile deposition precipitation method. The as-prepared samples have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and ultraviolet–visible absorption spectroscopy (UV–vis). The photocatalytic experiments indicate that the g-C3N4/BiOI/BiOBr composites possess enhanced photocatalytic activity towards the degradation of methyl orange (MO), and killing Escherichia coli. Photoluminescence (PL) spectra reveal that the introduction of g-C3N4 could efficiently promote the separation efficiency of photo-induced charge carriers in the composites. The radical trapping experiment and ESR analysis confirmed that the active species ·O2−, h+ and ·OH are the reactive oxygen species in the photocatalytic process. Our results suggest that the g-C3N4/BiOI/BiOBr composite photocatalysts can be used in water treatment of degrading the organic pollutants and killing the water bacteria at the same time.

Ni-doped TiO2 nanospheres decorated with silver plasmonic nanoparticles (Ni-TiO2/Ag) have been successfully synthesized via sol-gel method and photo-deposition approach. In contrast with pure TiO2 and Ni-TiO2, the Ni-TiO2/Ag composite photocatalysts exhibit markedly enhanced visible-light photocatalytic sterilization efficiencies towards Escherichia coli (E. coli). And more importantly, antifungal experiment reveals that the composite can also disinfect ca. 2.0 log10 cfu·mL−1 Fusarium graminearum (F. graminearum) macroconidia within 3 h. The highly efficient antimicrobial activities are ascribed to the introduction of Ni doping and Ag nanoparticles, which increases the visible light utilization and promotes the separation of electron-hole pairs. The photocatalytic disinfection mechanism is studied with scavengers trapping experiments and electron spin-resonance spectroscopy (ESR), which verifies the key role of •O2- and •OH during the microbial inactivation. Our study indicates that the Ni-TiO2/Ag nanocomposite has great potential for use in pathogenic microorganism remediation.

In this study, a series of highly efficient visible-light-driven Ag/AgCl/TiO 2 plasmonic photocatalysts were synthesized by a facile solvothermal method. Characterization results showed that the as-prepared nanocomposites of 10% Ag/AgCl/TiO 2 showed highly visible light photocatalytic activity, which could disinfect almost all of the Escherichia coli after 40 min treatment. Steady-state and transient photoluminescence spectroscopy indicated that the photocatalytic effect of Ag/AgCl/TiO 2 nanocomposites enhanced remarkably due to the reducing of electron-hole recombination and the increasing of charge separation during the photocatalytic reaction.

A class of red-emitting Eu3+ ion-activated metal molybdate A2MoO6:Eu3+ (A = La, Y, Gd and Bi) phosphors were synthesized by a conventional high-temperature solid-state reaction method. The x-ray diffraction patterns, scanning electron microscope images, Fourier transform infrared spectra, ultraviolet–visible diffuse reflection spectra as well as photoluminescence properties were measured to characterize the as-prepared samples. The photoluminescence properties including excitation/emission spectra, decay curves, Commission Internationale de L’Eclairage chromaticity coordinates and quantum efficiency were comparatively investigated in detail. The Judd–Ofelt theory was also applied to understand the radiative properties of f–f transitions of Eu3+ ions in this system for the first time. The as-prepared phosphors can be effectively excited with near-ultraviolet and/or blue light, and exhibit red emission belonging to the prevailing 5D0 → 7F2 transitions of Eu3+ with short decay time (millisecond level). The results demonstrated that A2MoO6:Eu3+ (A = La, Y, Gd and Bi) phosphors could have potential application as red-emitting phosphors in white light-emitting diodes based on near-ultraviolet and/or blue light-emitting diode chips.

TiO2/Ag2O heterostructure prepared by a facile in situ precipitation route was used as an effective visible light-driven photocatalyst for degradation of methylene blue (MB) and inactivation of E. coli. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed that Ag2O nanoparticles were well distributed on the surface of TiO2 microspheres. The TiO2/Ag2O composite with optimal mass ratio of TiO2 and Ag2O displayed extremely good photodegradation ability and antibacterial capability under visible light irradiation, which was mainly ascribed to the synergistic effect between Ag2O and TiO2, including highly dispersed smaller Ag2O particles, increased visible light absorption and efficient separation of photo-induced charge carriers. Meanwhile, the roles of the radical species in the photocatalysis process were investigated. Our results showed that the TiO2/Ag2O could be used as a dual functional material in water treatment of removing the organic pollutant and killing the bacterium at the same time.

This work reported the photoluminescence properties of novel red-light-emitting phosphor Ba2MgWO6:Eu3+ prepared by a conventional solid state reaction at high temperature. A broadband sensitized red emission was obtained in Ba2MgWO6:Eu3+ phosphor due to the energy transfer from W6+-O2− groups to Eu3+. The concentration quenching phenomenon and mechanism of Eu3+ in Ba2MgWO6 host was investigated in detail. Based on the obtained results, a series of g-C3N4/Ba2MgWO6:Eu3+ composite phosphors were also prepared. Under the excitation of ultraviolet light, these composite phosphors show tunable emission from blue to red region, in which white light emission can be obtained in term of appropriate quality proportion of g-C3N4 relative to Ba2MgWO6:Eu3+. This work not only develops a novel red-emitting phosphor for application in white light-emitting diodes, but also enlarges the research scope of g-C3N4 based materials.

A series of TiO2/Ag3PO4 heterostructures were fabricated via a facile in situ precipitation process. The as-synthesized composites were found to exhibit markedly enhanced photocatalytic inactivation of E. coli under visible light irradiation compared with bare TiO2 and Ag3PO4 owing to the improved light absorption and the efficient separation of photo-induced electron–hole pairs. Moreover, the antifungal activity of the composite materials was studied against the phytopathogen Fusarium graminearum (one of the main pathogens of wheat). With 100 min of visible light illumination, the TiO2/Ag3PO4 composite reduced the survival ratio of the F. graminearum macroconidia to about 2%. The photocatalytic disinfection mechanism of the macroconidia was attributed to the damage to their cell wall/membrane caused by the attack of reactive oxygen species as demonstrated by fluorescence staining. In addition, ESR measurement revealed that hydroxyl radicals were the predominant active species in the photocatalytic disinfection system. Our results suggest that this hybrid photocatalyst has great potential as an environmentally-friendly alternative method to disinfect plant pathogens for agricultural areas.

In this study, a heterostructure was prepared by two dimensional Na 2 W 4 O 13 flake and mixture of 0 dimensional WO 3 and PdO. Following that, the structure was characterized. TEM (transmission electron microscopy) results showed that the WO 3 particle loaded with PdO and decorated on surface of the two-dimensional Na 2 W 4 O 13 flake. Compared with WO 3 and Na 2 W 4 O 13 , the as-prepared 2-D composite showed an additional absorption band in the visible range (400–800 nm), which conduced to an improvement of the overall photonharvesting efficiency. At 0.5% mole ratio PdO loaded, the synthesized composite shows the highest photocatalytic disinfection activity under visible illumination, exceeding about four times than that of pure WO 3 and five times than that of pure Na 2 W 4 O 13 , respectively. By detecting PL spectroscopy (photoluminescence spectroscopy), the intensities of emission from 0.5% PdO loaded WO 3 /Na 2 W 4 O 13 composite were found to be weaker than those from other materials, which explained the higher disinfection activity of this composite.

Bacterial cells can be inactivated by external reactive oxygen species (ROS) produced by semiconductor photocatalysis. However, little is known about cellular responses to photocatalysis. For a better understanding of this issue, one strain of Escherichia coli ( E. coli, hereafter named as MT), which has an increased ability to metabolize carbon sources, was screened out from the wild-type (WT) E. coli K12 by repeated exposure to photocatalysis with palladium oxide modified nitrogen-doped titanium dioxide. In this study, transcriptome sequencing of the WT and MT strains that were exposed or unexposed to photocatalysis were carried out. Cellular responses to photocatalysis were inferred from the functions of genes whose transcripts were either increased or decreased. Upregulation of expression of bacterial flagellar assembly genes used for chemotaxis was detected in cells exposed to semilethal photocatalytic conditions of the WT E. coli. Increased capability to degrade superoxide radicals and decreased bacterial flagellar assembly and chemotaxis were observed in MT E. coli compared to WT cells. We conclude that the differences in motility and intracellular ROS between MT and WT are directly related to survivability of E. coli during exposure to photodisinfection.

The ultraviolet (UV)-emitting Sr3P4O13:Ce3+ phosphors were synthesized via the solid-state reaction method, and their structural, morphological and luminescence properties were characterized by X-ray diffraction analysis, scanning electron microscopy, photoluminescence spectroscopy. The obtained results indicate that these phosphors can be effectively excited by short-wavelength ultraviolet (

A series of Ce3+/Tb3+ co-doped Ba3La(PO4)3 phosphors were synthesized successfully via a high-temperature solid-state reaction, and their luminescence properties were investigated. The energy transfer phenomenon of Ce3+→Tb3+ in Ba3La(PO4)3 host was authenticated by relevant excitation spectra and decay curves, which leads to the change of luminous color for Ba3La(PO4)3:Ce3+, Tb3+ phosphors by tuning the quantity ratio of Ce3+ and Tb3+. Meanwhile, the Ce3+→Tb3+ energy transfer efficiencies were also calculated in this system. These results suggest that as-developed Ba3La(PO4)3:Ce3+, Tb3+ phosphors are potential single-component color-tunable phosphors.

A series of novel single-phase white-emitting phosphors based on Dy3+ doped strontium tetraphosphate (Sr3P4O13:Dy3+) have been synthesized successfully via a conventional solid-state reaction at high temperature, and characterized by X-ray diffraction, photoluminescence excitation/emission spectra and decay curves. The optimum doping concentration of Dy3+ in Sr3P4O13 was ascertained by investigating the influence of the doping concentration of Dy3+ on the emission intensity of Dy3+, in which the content of Dy3+ did not change the shape and position of emission spectra except for emission intensity. Meanwhile, the critical distance and concentration quenching mechanism were also calculated and confirmed. Furthermore, the decay time was also determined for Sr3P4O13:Dy3+ phosphors with various concentrations of Dy3+, and decreases gradually with increasing Dy3+ concentration. The as-prepared Sr3P4O13:Dy3+ phosphors could be excited by near ultraviolet, and exhibit white-light emission with short decay time of milliseconds, indicating these phosphors could exhibit certain potential as single-phase white-light-emitting phosphors for application in display and lighting regions (e.g. white light-emitting-diodes).

In this study, well-crystallized mesoporous anatase TiO2 spheres (TiO2-MS) were prepared via a simple sol–gel process followed by subsequent hydrothermal treatment and then used as photoelectrode for quantum-dot-sensitized solar cell (QDSC) application. The mesoporous structure exhibits efficient QD loading and good light-scattering properties for light harvesting. In the meantime, both surface photovoltage technique based on lock-in amplifier and transient photovoltage measurement reveal that the QDs-sensitized mesoporous TiO2 sphere photoelectrode is conducive to promote the separation of photo-induced charges and reduce the charge recombination owing to the efficient charge transfer. As a result, the QDSCs based on mesoporous TiO2 spheres photoelectrode shows a power conversion efficiency of 1.34 %, which is significantly higher than that derived from P25 nanoparticle electrode. The relation between the performance of QDSCs and their photovoltage characterization was also discussed.

CuInS 2 and CdS quantum dots (QDs) are sequentially assembled onto mesoporous TiO 2 film to prepare a CuInS 2 /CdS co-sensitized photoelectrode for QD-sensitized solar cell (QDSC) application. Our results show that the performance of a QDSC is strongly dependent on the order of CuInS 2 and CdS respected to the TiO 2 . When CuInS 2 is in between TiO 2 and CdS, the power conversion efficiency could reach 0.90%, while the efficiency decreased dramatically when the CuInS 2 QDs were on top of the layer (0.08%). Surface photovoltage (SPV) measurement revealed that the charge transfer from the cosensitizers toward the TiO 2 is much more efficient in the TiO 2 /CuInS 2 /CdS electrode rather than in the TiO 2 /CdS/CuInS 2 electrode. From the information on time-resolved photoluminescence (TRPL) technique, it was found that the average photoluminescence (PL) lifetime of TiO 2 /CuInS 2 /CdS electrode is shorter than that of the TiO 2 /CdS/CuInS 2 electrode, suggesting the higher carrier transfer rates between the heterointerfaces of CuInS 2 /CdS and TiO 2 /QDs. This study reported herein propose an innovative route to investigate the role of heterointerface in the carrier transfer mechanism and enable better design of highly efficient QDSCs.

In this study, we synthesized a series of rhodium-modified and Ti3+ self-doped TiO2 (Rh/Ti3+-TiO2) nanocomposites via the one-pot method. We prepared samples of Rh/Ti3+-TiO2, which were analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Electron Spin Resonance (ESR), and Uv-vis-NIR analysis. We found that the ability of TiO2 to absorb near-infrared and visible light was significantly improved by the Rh/Ti3+-TiO2 nanocomposites, due to Ti3+ doping as well as modification of Rh. The disinfection properties of these materials were tested using Staphylococcus aureus under visible light and NIR light excitations. The synthesized photocatalyst was found to exhibit significantly enhanced photocatalytic inactivation of S. aureus under both visible and NIR light irradiation, as compared to pure TiO2. This was particularly true with respect to the 5% Rh/Ti3+-TiO2 sample. Our results suggest that the Rh/Ti3+-TiO2 composites could extend the range of optical response range of pure nano TiO2 materials to the Vis -NIR region.

In this study, Ti3+ self-doped TiO2 decorated with metallic copper photocatalyst (marked as Cu/Ti3+-TiO2) was successfully prepared by a novel method. The ESR (Electron Spin Resonance) analysis indicated that the synthesized sample contained Ti3+. The TEM (transmission electron microscopy) images showed that the TiO2 nanoparticles were modified with nano copper. The as-synthesized photocatalyst was found to exhibit markedly enhanced photocatalytic inactivation of E. coli under visible light irradiation compared with pure TiO2, especially in the case of the 10% Cu/Ti3+-TiO2 sample. The photodisinfection effect of the 10% Cu/Ti3+-TiO2 sample was further confirmed using five agricultural pathogenic fungal spores. The photocatalytic inactivation effect against F. graminearum and Botryosphaeria dothidea spores was certified by fluorescent staining of CFDA-AM (the acetoxymethyl ester of the esterase substrate 5-carboxyfluorescein diacetate)/PI (Propidium Iodide). In addition, fluorescent staining by H2DCFDA demonstrated that the intracellular ROS (reactive oxygen species) of the F. graminearum macroconidia was increased after treatment by the photocatalysis.

TiO2/Cu2(OH)2CO3 nanocomposite were synthesized via a simple in-situ precipitation process, which was applied as efficient antimicrobials for the inactivation of Escherichia coli (E. coli) and Fusarium graminearum (F. graminearum) under simulated solar light. With optimum Cu2(OH)2CO3 amount of 1.8 mol%, the TiO2/Cu2(OH)2CO3 nanocomposite presented the highest antimicrobial activities against E. coli and F. graminearum, and achieved complete inactivation in 80 min, which was far better than that of bare TiO2. The boosted photocatalytic disinfection efficiency was ascribed to the increased light harvesting and efficient charge transfer and separation in the TiO2/Cu2(OH)2CO3 nanocomposite, which resulted in more efficient generation of •OH and •O2- that played important role in the photocatalytic inactivation process. Our work revealed that TiO2/Cu2(OH)2CO3 composite was a promising antimicrobial agent for prevention of pathogenic fungal or bacterial infections in crop protection.