Facile synthesis of Bi2ZnB2O7-MoS2nanocomposite for photodetector and photocatalytic Rhodamine B dye degradation application.

In this research, the visible light active performance of Bi2ZnB2O7(BBZO) was significantly enhanced through the formation of a composite with few layer MoS2. The resultant MoS2@BBZO catalyst was employed in both photocatalysis and photodetector applications. Comprehensive structural and morphological analyses of the MoS2@BBZO catalyst were conducted using x-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy. The estimated band gaps of BBZO and the composite were found to be 2.8 eV and 1.74 eV, respectively. Rhodamine B degradation studies demonstrated that the catalyst achieved 75% degradation within 30 min. Additionally, the photodetector application was investigated, revealing rapid photo-switching capabilities and an increased photocurrent.

Electronic Structure and Chemical Bonding of the First-, Second-, and Third-Row-Transition-Metal Monoborides: The Formation of Quadruple Bonds in RhB, RuB, and TcB.

Boron presents an important role in chemistry, biology, and materials science. Diatomic transition-metal borides (MBs) are the building blocks of many complexes and materials, and they present unique electronic structures with interesting and peculiar properties and a variety of bonding schemes which are analyzed here. In the first part of this paper, we present a review on the available experimental and theoretical studies on the first-row-transition-metal borides, i.e., ScB, TiB, VB, CrB, MnB, FeB, CoB, NiB, CuB, and ZnB; the second-row-transition-metal borides, i.e., YB, ZrB, NbB, MoB, TcB, RuB, RhB, PdB, AgB, and CdB; and the third-row-transition-metal borides, i.e., LaB, HfB, TaB, WB, ReB, OsB, IrB, PtB, AuB, and HgB. Consequently, in the second part, the second- and third-row MBs are studied via DFT calculations using the B3LYP, TPSSh, and MN15 functionals and, in some cases, via multi-reference methods, MRCISD+Q, in conjunction with the aug-cc-pVQZ-PPM/aug-cc-pVQZB basis sets. Specifically, bond distances, dissociation energies, frequencies, dipole moments, and natural NPA charges are reported. Comparisons between MB molecules along the three rows are presented, and their differences and similarities are analyzed. The bonding of the diatomic borides is also described; it is found that, apart from RhB(X1Σ+), which was just recently found to form quadruple bonds, RuB(X2Δ) and TcB(X3Σ-) also form quadruple σ2σ2π2π2 bonds in their X states. Moreover, to fill the gap existing in the current literature, here, we calculate the TcB molecule.

Zinc and cadmium change the metabolic activities and vegetable cellulose degradation of Bacillus cellulasensis in vegetable soils.

Bacillus cellulasensis Zn-B isolated from vegetable soil was highly adaptable to Zinc (Zn) and Cadmium (Cd). Cd, but not Zn, adversely affected the total protein spectrum and functional groups of Bacillus cellulasensis Zn-B. Up to 31 metabolic pathways and 216 metabolites of Bacillus cellulasensis Zn-B were significantly changed by Zn and Cd (Zn&Cd). Some metabolic pathways and metabolites related to functional groups of sulfhydryl (-SH) and amine (-NH-) metabolism were enhanced by Zn&Cd addition. The cellulase activity of Bacillus cellulasensis Zn-B was up to 8.58 U mL-1, increased to 10.77 U mL-1 in Bacillus cellulasensis Zn-B + 300 mg L-1 Zn, and maintained at 6.13 U mL-1 in Bacillus cellulasensis Zn-B + 50 mg L-1 Cd. The vegetables' cellulose content was decreased by 25.05-52.37% and 40.28-70.70% under the action of Bacillus cellulasensis Zn-B and Bacillus cellulasensis Zn-B + 300 mg L-1 Zn. Those results demonstrated that Zn could significantly enhance cellulase activity and biodegradability of Bacillus cellulasensis Zn-B to vegetable cellulose. Bacillus cellulasensis Zn-B can survive in vegetable soil accumulated with Zn&Cd. The tolerance concentration and adsorption capacity of Bacillus cellulasensis Zn-B to Zn were up to 300 mg L-1 and 56.85%, indicating that Bacillus cellulasensis Zn-B acting as a thermostability biological agent had an essential advantage in accelerating the degradation of discarded vegetables by Zn and were beneficial to maintain organic matter content of vegetable soil.

Thermoluminescence spectra of Tm doped ZnB2O4 phosphor prepared via a wet-chemical synthesis.

In this paper we describe the thermoluminescence (TL) characteristics of 0.8 mol% Tm3+ doped ZnB2O4phosphors prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of three peaks located at 181 °C, 213 °C and 351 °C. The glow peak TL temperature (Tm) at which the TL glow peak occurs shifts toward the higher temperature side whilst the heating ramp rate increases and also the peak TL intensity (Im) decreases. The TL glow curves are characterized by evaluating various dosimetric characteristics of scrutinized samples. The Tm-Tstopinvestigations on regenerated TL signals revealed that there are five different traps in the phosphor with energy values in the range of 0.61-1.71 eV. The dose responses increased in a linear way for 3 peaks with the beta-ray exposure in the dose range of 0.11-60 Gy. The process of applying 10 Gy dose was repeated for ten successive irradiation cycles to check reproducibility and the maximum variation was found to be less than 1% from the average value. These results provide valuable knowledge for use of the characteristics of Tm doped ZnB2O4 in dosimetry research.

Luminescence studies of zinc borates activated with different concentrations of Ce and La under x-ray and electron excitation.

Several ZnB2O4 powder samples having dopants concentrations of 0.1, 0.01, 0.04wt% Ce and La were prepared using the nitric acid method via the starting oxides. Several complementary methods such as powder X-ray diffraction (XRD), thermal analyses environmental scanning electron microscopy (ESEM), Radioluminescence (RL) and Cathodoluminescence (CL) techniques were used. Unique luminescence properties of Ce doped ZnB2O4 powder samples are reported for the first time. A new luminescence bands appearing in red part of the spectrum and having all the characteristics of Ce3+ were obtained from RL results. Changing the Ce and La concentration of 0.01-0.1wt% leads to an increase in RL and CL intensities of Ce3+ and La3+ ions and also CL emission spectra of ZnB2O4 show gradual shift towards longer wavelength. When we compare the luminescence intensity of the samples it is seen that Ce doped ZnB2O4 has the highest intense whereas La doped ZnB2O4 has the lowest one. However, emission spectra of both Ce and La doped samples kept unchanged.

Crystal structures of the solid solutions Na3Zn0.912Cd0.088B5O10 and Na3Zn0.845Mg0.155B5O10.

Two new penta-borates, tris-odium zinc cadmium penta-borate, Na3Zn0.912Cd0.088B5O10, and tris-odium zinc magnesium penta-borate, Na3Zn0.845Mg0.155B5O10, have been synthesized by high-temperature solution reactions at 1023 K. Their crystal structures were determined by single-crystal X-ray diffraction. Both solid solutions crystallize in the ortho-rhom-bic form of the parent compound Na3ZnB5O10 (space group type Pbca, Z = 8) and contain the double ring [B5O10]5- anion composed of one BO4 tetra-hedron and four BO3 triangles as the basic structural motif. The anions are bridged by tetra-hedrally coordinated and occupationally disordered M2+ (M = Zn/Cd, Zn/Mg) cations via common O atoms to form [MB5O10] n3n- layers. The intra-layer inter-secting channels and the inter-layer voids are occupied by Na+ cations to balance the charge.

Normal and anomalous heating rate effects on thermoluminescence of Ce-doped ZnB2O4.

The effect of heating rate (HR) on thermoluminescence (TL) glow curves of 1%, 4%, and 10% Ce3 + doped ZnB2O4 phosphors was investigated in detail. The glow peaks are examined and, activation energy (E) and frequency factor (s) are determined by using various heating rate (VHR) method. In the obtained glow curves with nine different HRs between 2 and 10°C/s, it was observed that the TL intensities of the first peaks of all three samples and the second peak of 10% Ce3 + doped sample decrease with increasing HR. The decrease in TL intensity was investigated whether it may be due to the presence of thermal quenching or not. On the other hand, the second glow peaks of 1, 4% Ce3 + doped ZnB2O4 phosphors show an anomalous TL behavior, which the probability of the radiative processes increases due to recombination of free electrons, so the TL intensity increases with the HR. The graphs of full width at the half maximum (FWHM) versus HR were also plotted to evaluate the influence of HR on TL intensity. In this paper, we suggest that the non-localized Schön - Klasens model may give an explanation for the second peaks of 1, 4% Ce3 + doped ZnB2O4 phosphors showing an unexpected increase with the increasing HR. In addition, the calculated E values of all doped phosphors were found similar in the range of 0.47-0.53eV for peak 1 and 0.61-0.66eV for peak 2. However, s values of Ce3 + doped ZnB2O4 phosphors were found slightly different according to the dopant amount and the equation used. Furthermore, different amount of Ce3 + doped samples indicate the similar properties for the repeated cycles of 5Gy in the same irradiation conditions.

Thermoluminescence kinetic parameters of different amount La-doped ZnB2O4.

The kinetic parameters of 1%, 2%, 3% and 4% La-doped ZnB2O4 phosphors (i.e. ZnB2O4:0.01La, ZnB2O4:0.02La, ZnB2O4:0.03La and ZnB2O4:0.04La) synthesized by nitric acid method have been calculated. Thermoluminescence (TL) glow curves of ZnB2O4:La phosphors after beta-irradiation showed a very well defined main peak having the maximum temperature at around 200°C and a shoulder peak at around 315°C with a constant heating rate of 5°C/s. The kinetic parameters of ZnB2O4:La phosphors TL glow peaks (i.e. order of kinetics (b), activation energies (Ea) and frequency factors (s)) have been determined and evaluated by Computerized Glow Curve Deconvolution (CGCD), and Peak Shape (PS) methods using the glow curve data. From the results, it can conclude that the values of Ea obtained with these methods for ZnB2O4:La phosphors are consistent with each other, but the s values differ considerably.