Hengzhen Shi

Visible-light-driven TiO2/Ag3PO4 heterostructures with enhanced antifungal activity against agricultural pathogenic fungi Fusarium graminearum and mechanism insight

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.

Synthesis and Luminescence Properties of Eu3+ Doped High Temperature Form of Bi2MoO6

This work reports on the luminescence properties of the Eu3+-doped high-temperature form of Bi2MoO6 by a solid-state reaction technique at high temperature. Various characterization methods including x-ray diffraction, scanning electron microscopic, Fourier transform infrared, and fluorescence spectroscopy measurements were utilized in order to investigate the phase purity and surface morphology as well as photoluminescence properties for as-prepared phosphors. The spectroscopic characteristics including excitation and emission spectrum, concentration quenching phenomenon, decay curves, and chromaticity coordinates are discussed in detail. The nature of the luminescence behavior of Eu3+ was understood in term of the Judd–Ofelt theory, and the luminescent quantum efficiency of 5D0 → 7F2 transition of Eu3+ was estimated. The as-prepared phosphors can be effectively excited with a 465-nm blue light, and exhibit a reddish-orange emission belonging to the prevailing 5D0 → 7F2 transition of Eu3+ with a decay time of milliseconds. This indicates that the Bi2MoO6:Eu3+ phosphors could have potential application in white light-emitting diodes (w-LEDs) based on blue LED chips.

LUMINESCENCE PROPERTIES OF NOVEL SINGLE-HOST WHITE-LIGHT-EMITTING PHOSPHOR KBABP2O8:DY3+

A series of white-light-emitting KBaBP2O8:Dy3+ phosphors were synthesized by using a solid state reaction technique at high-temperature. X-ray diffraction and fluorescence spectroscopy measurements were utilized to characterize the structure and luminescence characteristics including excitation and emission spectra, decay curves, chromaticity coordinates of the assprepared phosphors. The influence of the doping concentration of Dy3+ on the relative emission intensity of Dy3+ was investigated. The critical distance as well as concentration quenching mechanism was calculated and confirmed. The as-prepared phosphors can be effectively excited with near ultraviolet, and exhibit white light emission with short decay time of milliseconds. The above work indicates these phosphors could be potential candidates as single-host white-light-emitting phosphors for application in white light-emitting-diodes.

Ti[BP2O7(OH)3]: The first titanium borophosphate containing novel anionic partial structure

The first titanium borophosphate Ti[BP2O7(OH)3] has been hydrothermally synthesized and structurally characterized. The compound has a three-dimensional open-framework architecture by linking TiO6 octahedra to the anionic layers [BP2O7(OH)3]4− which are built up from BO3(OH) tetrahedra and PO3(OH) tetrahedra. The compound not only represents the first transition metal titanium(IV) borophosphate but also displays the novel two-dimensional layered borophosphate anionic partial structure.

KBaBP2O8:Tm3+: a novel blue-emitting phosphor with high color purity

A series of novel blue emitting K1 + xBa1 − 2xTmxBP2O8 (0.01 ≤ x ≤ 0.08) phosphors were synthesized by a solid-state reaction at a high temperature for the first time. The phase purity and photoluminescence properties were investigated by X-ray diffraction (XRD) and fluorescence spectroscopy (FS) measurements, respectively. The influence of the doping concentration of Tm3+ on its relative emission intensity was investigated, and the critical distance was calculated. The as-prepared phosphor can be effectively excited with a 356-nm light, and exhibit blue emission at 457 nm with high color purity. The above work indicates this phosphor could be a potential candidate as blue emitting phosphor for application in white light-emitting diodes.

A novel chlorine-containing borophosphate based on (4,3)-connected 3-D borophosphate anion [B6P11O42(OH)2]13− with unique B : P ratio and 22-tetrahedral cages

A novel chlorine-containing borophosphate Na13(H3O)2 [B6P11O42(OH)2]Cl2·H2O has been hydrothermally synthesized and structurally characterized. The compound not only possesses a unique B : P ratio of 6 : 11, but also displays a novel (4,3)-connected three-dimensional borophosphate anionic partial structure containing 22-tetrahedral cages.

Synthesis of g-C 3 N 4 /BiOI/BiOBr heterostructures for efficient visible-light-induced photocatalytic and antibacterial activity

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.

Facile synthesis of g-C3N4/amine-functionalized MIL-101(Fe) composites with efficient photocatalytic activities under visible light irradiation

Abstractg-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.

Carbon dots-decorated Na2W4O13 composite with WO3 for highly efficient photocatalytic antibacterial activity

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).

Luminescence properties of a novel single-phase white-emitting phosphor based on Dy3+ doped strontium tetraphosphate

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).