Structure Of As-synthesized Samples Research Articles

Development of Bi2O3/MoSe2 mixed nanostructures for photocatalytic degradation of methylene blue dye

Herein, we demonstrate the sample and low coast hydrothermal synthesis of a nanocomposite of Bi2O3/MoSe2 for hybrid photocatalyst. The structure of as-synthesized samples was characterized by using several techniques, including XRD spectroscopy, Raman spectroscopy, XPS, SEM, BET, and UV-visible absorption spectroscopy. The nitrogen adsorption–desorption measurements show that the samples have a mesoporous texture with slits like pores. The Bi2O3/MoSe2 nanocomposite had BET surface areas of 36.439 m2/g, which were more than those of Bi2O3 (18.342 m2/g) and MoSe2 (12.923 m2/g). Under visible illumination, the photocatalytic activities of pure samples ( Bi2O3 and MoSe2) and the hybrid Bi2O3/MoSe2 sample for the disintegration of methylene blue were assessed. The results show that the Bi2O3/MoSe2 sample showed the highest photocatalytic degradation efficiency (i.e. 96.5% after an exposure time of 80 min). The increased photocatalytic activity is due to the mixed sample's high crystallinity and surface area, as well as the small particle size.

Uncovering the replacement of Zn2+ ions on nano-structural, opto/magneto/electrical, antibacterial and antifungal attributes of nickel oxide nanoparticles via sol-gel strategy

Transition metal oxides have gathered momentum among the scientific community on account of their peculiar procession in physico-chemical, opto-electronic, magnetic, electro-chemical, and biological attributes resulting from anisotropic charge distribution of partly filled d-orbitals, non-stoichiometric behaviour, and diverse oxidation states of the cations. The current work emphasize on the systematic synthesis and characterization of pristine and zinc (Zn) incorporated nickel oxide (NiO) nanoparticles in varying concentrations ZnxNi1-xO (x=0, 0.1, 0.2, and 0.3) via a scalable sol-gel approach assisting citric acid (C6H8O7) as a congealing factor. A series of extensive analyses were executed to investigate the structural, opto-electrical, and magnetic characteristics of prepared nanoparticles. X-Ray Diffraction (XRD) studies confirmed the face-centered cubic structure of as-synthesized samples and the corresponding crystallite size is found to decrease with an increasing dopant concentration as estimated from the Scherrer method. Scanning Electron Microscopy (SEM) studies portrayed the spherical structure and porous nature of NiO nanoparticles. Particle size calculated from SEM shows the decreasing trend with dopant discrepancy which is in accordance with crystallite size measured from XRD results. Energy Dispersive X-ray (EDX) spectra revealed the presence of estimated molecular assembly in synthesized samples. The cubic configuration and the presence of functional groups existing in synthesized nanoparticles were endorsed from Fourier Transform Infra-Red (FTIR) spectroscopy operated in the vibrational IR frequency region. The optical absorption spectrum examined from Ultra Violet-visible (UV–vis) spectroscopy evaluates the energy bandgap and it is noticed to increase from 2.48 to 2.87 ​eV affirming the Burstein Moss shift. The energy dispersion of optical parameters plays a crucial contribution in optical materials pursuant to its prominence in optical communications and in fabricating novel devices for spectral dispersion. Optical and energy dispersion parameters evaluated from Wemple-DiDomenico (WDD) model and non-linear optical parameters were deliberated from optical studies. The performance of integrated optical systems such as monochromatic filters, optical and electrical switches, laser diodes, detectors, and amplifiers can be controlled by the dispersion parameters. Urbach energy and another pivotal optical criterion highly correlated with the bandgap energy anchored in the fabrication of optoelectronic devices were assessed. The electrical characteristics such as dielectric constant, loss, and conductivity exhibited by pure and Zn doped nickel oxide nanoparticles were reported. Molecular electronic polarizability assessed through elementary solid-state parameters is in better concurrence with diverse relations like Clausius-Mossotti, Lorentz-Lorent, bulk modulus, optical electronegativity, and energy band gap. The pore size distribution of substance matrix and the associated surface area were elucidated from Brunauer-Emmett-Teller (BET) analysis. Dispersive magnetic properties and two pivotal parameters were derived from the Law of Approach to Saturation (LAS) operandi. Further, microbial cell mechanism was illustrated through nano-architecture design, and the antibacterial and antifungal activity encountered by undoped and zinc doped NiO nanoparticles against different microbial strains were deeply discussed for pilot production of antimicrobial agents.

Synthesis, characterization and photocatalytic parameters investigation of a new CuFe2O4/Bi2O3 nanocomposite

Synthesis of heterojunctions to improve the efficiency of photocatalyst and charge-transfer properties has been a major concern recently. A novel photocatalyst copper ferrite-bismuth oxide (CuFe2O4/Bi2O3) nanocomposite was synthesized with unique magnetic properties. In this nanocomposite catalyst, the nano-petals of bismuth oxide (Bi2O3) were entangled with CuFe2O4 particles via the ultra-sonication method. The structure of as-synthesized samples was investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), whereas the morphology and optical band gap was determined using field emission scanning electron microscopy (FESEM) and UV–Vis spectrophotometry. Comparative photocatalytic activity of copper ferrite and the nanocomposite was examined for the degradation of Methylene Blue (MB) dye. The superior performance of photocatalyst is attributed to the visible light sanitizer; CuFe2O4 could assist Bi2O3 to absorb more photons of incident light which promotes the production of photoexcited electron-hole pairs. Additionally, the catalyst could be recycled and separated from the dye without any loss of photocatalytic efficiency owing to good chemical stability as well as magnetic separation.

Composite particles with dendritic mesoporous-silica cores and nano-sized CeO2 shells and their application to abrasives in chemical mechanical polishing

The structure and mechanical/chemical performance of particle abrasives in polishing slurries play an important role in chemical mechanical polishing (CMP) processes. In the present paper, the CeO2-based novel abrasive particles containing dendritic mesoporous silica (D-mSiO2) cores and nano-sized CeO2 shells present potential applications in high-efficiency and defect-free CMP, resulting from their special mechanical and/or chemical characteristics. The D-mSiO2 cores of composites were prepared via a modified biphase stratification approach, and the nano-sized CeO2 particles were coated via an in-situ chemical precipitation technique. The composition and structure of as-synthesized samples were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, and nitrogen sorption-desorption measurements. The effect of the core category for the CeO2-based composite particles on oxide-CMP performance was evaluated in termers of material removal rate (MRR) and root-mean-square (RMS) roughness (determined by atomic force microscopy). Experimental results indicated that the as-obtained D-mSiO2/CeO2 abrasives exhibited a comparable RMS roughness (0.18 ± 0.02 nm) with respect to the polystyrene/CeO2 abrasives (0.15 ± 0.02 nm) with polymer cores. However, the MRR of the D-mSiO2/CeO2 abrasives (85 nm/min) was three times larger than that of the PS/CeO2 abrasives (26 nm/min). The enhanced polishing efficiency may be attributed to the differences of the mechanical behavior and surface atom structure of the nano-sized CeO2 particles of the composites after treatment by high-temperature calcination. The improved oxide-CMP behavior of D-mSiO2/CeO2 composite particles may result from the spring-like effect coming from the elastic component of the cores, and the enhanced surface hardness and tribo-chemical activity of CeO2 particles in the shells.

Synthesis of PVP Coated Superparamagnetic Iron Oxide Nanoparticles with a High Saturation Magnetization

Superparamagnetic iron oxide nanoparticles (SPION) were synthesized by one pot coprecipitation method at room temperature in the presence of Polyvinylpyrrolidone (PVP). X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Vibrating Sample Magnetometer (VSM) were used to analysis the physicochemical properties of PVP-SPION. The XRD patterns confirmed that the structure of as-synthesized sample is magnetite with cubic structure system. In TEM results, the image of PVP-SPION displayed that the size of particles was 14.05 nm with narrower size distribution and also the PVP played important role to minimize the agglomeration of SPION. Finally, the high saturation magnetization value of PVP-SPION (53.0 emu/g) indicate the as-synthesized sample has a great potential as a contrast agent for MRI.

Synthesis and Photocatalytic Activity of Visible-Light Responsive BiOBr/GO Composites

High efficiency BiOBr/GO composites photocatalyst were successfully synthesized via a facile precipitation method. The precursors were prepared by dissolving Bi (NO3)3.5H2O and KBr in glycerol and distilled water, respectively. Various amounts (0.1-2 wt%) of graphene oxide were added into the mixed solution precursors, and stirred at room temperature to get precipitated powder without further heat treatment. The obtained products were characterized for phase, morphology, optical properties and surface area by X-ray diffraction (XRD), transmission electron microscopy (TEM), filed-emission scanning electron microscopy (FE-SEM), UV-Vis diffuse reflection spectroscopy (DRS) and Brunauer–Emmett–Teller (BET), respectively. The morphology and structure of as-synthesized samples were composed of numerous fine plates of BiOBr dispersed on the GO sheets. The photocatalytic activities of BiOBr/GO composites were evaluated by rhodamine B degradation under visible light irradiation. As the results, the significant increase in photodegradation of BiOBr/GO composite comparing with pure BiOBr was observed. Among all samples, the composite with 1 wt% of graphene oxide showed the highest photocatalytic performance.

Fabrication of Novel CuO Films with Nanoparticles-Aggregated Sphere-Like Clusters on ITO and Their Nonenzymatic Glucose Sensing Applications

In this work, novel nanoparticles-aggregated CuO sphere-like clusters were successfully synthesized on indium tin oxide (ITO) glass through a facile two-step procedure consisting of the fabrication of Cu2O films directly grown on ITO surface by electrodeposition, and subsequent calcinations of Cu2O films leading to the formation of CuO films. The morphology and structure of as-synthesized samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the size of nanoparticles constituting sphere-like clusters structure obtained at 200[Formula: see text]C is much smaller than that of obtained at other temperature, which can provide large surface area for catalytic reaction. The CuO/ITO electrode was applied to detect glucose by cyclic voltammetry (CV) and amperometric detection ([Formula: see text]). It was found that the obtained CuO films modified ITO electrode exhibited a much higher electrocatalytic activity for the oxidation of glucose in an alkaline medium through heat treatment of 200[Formula: see text]C. A favorable performance with a high sensitivity of 1841.5544[Formula: see text][Formula: see text]A mM[Formula: see text] cm[Formula: see text] to glucose ranging from 1.0[Formula: see text][Formula: see text][Formula: see text]10[Formula: see text][Formula: see text]M to 5.0[Formula: see text][Formula: see text][Formula: see text]10[Formula: see text][Formula: see text]M, a low operating potential of 0.35 Vversus Ag/AgCl and a fast amperometric response (within 3[Formula: see text]s) were achieved on such CuO/ITO electrode. It also showed outstanding long-term stability and good reproducibility. Notably, poisoning by chloride ions and interference from ascorbic acid, uric acid and acetaminophen were negligible. Therefore, the nanoparticles-aggregated CuO sphere-like clusters would be a promising candidate electrode material for the development of nonenzymatic glucose sensors.

Tollen's-assisted preparation of Ag3PO4/GO photocatalyst with enhanced photocatalytic activity and stability

Ag3PO4–graphene oxide (GO) composites were fabricated via a Tollen's -assisted method, which displayed outstanding photocatalytic activity for MB degradation under the visible light illumination. The samples were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrometer, UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL). The morphology and structure of as-synthesized samples were like-cubic particles scattered onto the GO nanosheets, suggesting that the fabrication of [Ag(NH3)2]+–GO complexes were synthesized during the forming of Ag3PO4 /GO composites. Compared with Ag3PO4, UV–vis DRS demonstrated that the addition of GO sheets resulted in the band gap of Ag3PO4/GO sample decrease to 2.03eV. Meanwhile, during the photocatalytic process the photo-electrons were transferred from the surface of Ag3PO4 to GO nanosheets, which improved the photocatalytic performance and stability of Ag3PO4.

Energy transfer and heat-treatment effect of photoluminescence in Eu 3+-doped TbPO 4 nanowires

We have successfully synthesized Eu 3+-doped TbPO 4 nanowires, which are orderly organized to form bundle-like structure. A thermal treatment up to 600 °C does not modify the size, shape and structure of as-synthesized sample. Due to the energy overlap between Tb 3+ and Eu 3+, an efficient energy transfer occurs from Tb 3+ to Eu 3+. The effects of Eu 3+ concentration and thermal treatment on the luminescent properties of Eu 3+ are investigated. The increase of Eu 3+ concentration leads to the increase of the energy transfer efficiency from Tb 3+ to Eu 3+, but also enhances the probability of the interaction between neighboring Eu 3+, which results in the concentration quenching. With the heat-treatment, the luminescence of Eu 3+ presents an obvious increase, but almost no change for the luminescence of Tb 3+. This difference is explained based on the TGA, DTA, and fluorescent decay dynamics analyses.

Magnetic Properties of Fe-Pt Nanoparticle Protected by PVP Polymer

Annealing effect on the magnetic properties of Fe-Pt nanoparticle was investigated. Fe-Pt nanoparticles were synthesized by the chemical reduction of H2PtCl6 and the decomposition of Fe(CO)5 in the presence of PVP polymers. The samples were annealed at several temperatures from 350°C to 600°C and the structural and magnetic properties were studied by TEM, XRD and magnetization measurements. FePt nanoparticles as-synthesized showed super-paramagnetism and annealed samples at temperatures more than 400°C, ferromagnetism. The crystal structure of as-synthesized sample was disordered fcc, but chemically ordered fct, when it was annealed at more than 400°C. The annealing effects are the concatenation or agglomeration of nanoparticles accompanied with the increase in particle diameter and with the ordering of the FePt superlattice. The critical diameter for emergence of ferromagnetism of FePt particle has been considered to be 3.6 to 5.6 nm in mean diameter, under the existence of the ordered L10 phase The blocking temperature as a function of the annealing temperature was investigated.

Characterization and synthesis of pure ZrO 2 nanopowders via sonochemical method

Pure ZrO 2 nanopowders have been synthesized via sonochemical method, which is a simple and energy efficient way to synthesize inorganic materials. The as-synthesized samples (hydrous zirconia, ZrO 2· nH 2O) are characterized by several techniques: X-ray diffraction (XRD), thermogravimetric analysis (TGA), photoluminescence spectrometer (PLS) and Raman spectrometer (RS). It is shown that t-ZrO 2 samples have two photoluminescence (PL) bands corresponding to the wavelengths of excitations of 254 and 412 nm. The structure of as-synthesized samples (ZrO 2· nH 2O) and the formation mechanism of ZrO 2 nanopowders are also discussed.