Search

SnS-Ti/TiO2photoanode for anticancer drug degradation.

We report a successful synthesis of a ternary AlB2-type intermetallic compound. The phase purity was obtained by fine-tuning the Pd : Ge ratio out of the idealized 1 : 3. Attempts to synthesize an Er analogue were not successful. We discuss the instability of the Er analogue based on the atomic size ratio and also suggest that the increased stability of Ho2Pd1+xGe3−x in the Pd-rich range likely stems from a combination of atomic size ratio, electronic, and entropic factors. The new Ho2Pd1.3Ge2.7 compound is found to exhibit cluster glass behavior with a freezing temperature of T ≈ 2.3 K.

The effect of hexadecyltrimethylammonium bromide (CTAB) addition on the crystal structure, morphology, and magnetic properties of co-precipitated hexagonal barium ferrite was investigated. For a fixed amount of surfactant, different Fe3+ concentrations and Fe3+/Ba2+ ratios were used to optimize the formation of single-phase barium ferrite particles. The results indicated that the obtained ferrite particles exhibited coercivity changes similar to those of superparamagnetic particles with larger than theoretically calculated particle sizes. This results from the softening of the material due to the size reduction of the grains and incorporation of excess barium, localized on the surface of the particles. Therefore, lowering the energy barrier required to reverse the magnetization was observed, while high magnetization saturation was preserved. The precipitation of barium ferrite particles from a surfactant-rich solution allowed control of BaFe12O19 magnetic properties without introducing any modifications inside the crystal structure.

Novel visible light responsive materials for water splitting are essential for the efficient conversion of solar energy into hydrogen bond energy. Among other semiconductors, gadolinium orthovanadate has appropriate conduction and valence band edges positioned to split water molecules and a narrow band gap that allows the use of visible light for hydrogen generation. Thus, we present here that hydrogen evolution under visible light (λ > 420 nm) could be accomplished using hierarchical 3D GdVO4 particles, obtained by a simple, one pot hydrothermal synthesis. We found that applying various reaction components, such as EDTA-Na2 and EDTA, and adjusting the pH of the solution allow one to tune the shape of GdVO4 (such as short nanowires, long nanowires, short nanorods, long nanorods, nanoparticles and spheres – all having a tetragonal crystal structure) as well as optical and photocatalytic properties. The highest ability to photocatalytically split methanol solution into hydrogen under UV-Vis irradiation was detected for the long nanowire sample (42 μmol h−1), having almost 11 times higher efficiency in comparison with the weakest sample – short nanowires. In addition, GdVO4 spheres generated H2 more than 2 times (5.75 μmol h−1) in comparison with the short nanorod sample (2.5 μmol h−1) under visible light excitation. Photostable in three-hour work cycles, long nanowires and spheres were even able to generate hydrogen from pure water, reaching values of 17 and 3 μmol under UV-Vis and Vis light, respectively.

Following the predictions of total energy calculations, a tetragonal SrMn2P2 phase is proposed and successfully formed under high pressure. At ambient pressure, SrMn2P2 adopts the primitive trigonal La2O3 structure type (space group P3[combining macron]m1). However, the results of total energy calculations indicate that SrMn2P2 should be more stable in the tetragonal ThCr2Si2 structure type (space group I4/mmm) than in its known trigonal structure, thus motivating our synthetic experiments. Guided by these calculations, a new tetragonal polymorph of SrMn2P2 was found under the relatively mild conditions of 5 GPa applied pressure at a temperature of 900 °C through the transformation of the ambient pressure trigonal form. The new polymorph has the body centered tetragonal ThCr2Si2 structure type, as predicted. The electronic structure calculations indicate the likelihood of antiferromagnetic, semiconducting properties for the high pressure SrMn2P2 phase.

Novel rGO–KTaO3 composites with various graphene content were successfully synthesized using a facile solvothermal method which allowed both the reduction of graphene oxide and loading of KTaO3 nanocubes on the graphene sheets. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) specific surface area, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV-Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) emission spectroscopy. The obtained rGO–KTaO3 composites showed greatly improved photocatalytic performance for degradation of phenol under visible light irradiation (λ > 420 nm) over pristine KTaO3 which could be related to the photosensitizer role of graphene in the rGO–KTaO3 composites as well as the formation of p–n heterojunctions between KTaO3 nanocubes and rGO sheets. The highest photocatalytic activity in phenol degradation reaction was observed for rGO–KTaO3 hybrid with 30 wt% graphene. The enhanced photoactivity of this composite could be attributed to the synergistic effect of several factors such as: small crystallite size, extended absorption range in the visible spectrum and intimate contact between graphene and KTaO3 cubes.