An electrochemical investigation on (MoO3+PVP+PVA) nanobelts for lithium batteries

Fabrication of a Three-Dimensionally Networked MoO3/PPy/rGO Composite for a High-Performance Symmetric Supercapacitor

A three-dimensionally interconnected molybdenum trioxide (MoO₃)/polypyrrole (PPy)/reduced graphene oxide (rGO) composite was synthesized via an eco-friendly three-step method. The as-obtained electrode shows a high specific capacity of 412.3 F g^-1 at a current density of 0.5 A g^-1 and a good cycling stability (85.1% of the initial specific capacitance after 6000 cycles at 2 A g^-1 is retained), and these excellent electrochemical performances can be attributed to the unique structure, remarkable electrical conductivity, and the synergetic effects between MoO₃, PPy, and rGO. Furthermore, a symmetric supercapacitor based on a MoO₃/PPy/rGO electrode was assembled to investigate the practical application performance of this material. The results demonstrate a high energy density of 19.8 W h kg^-1 at a power density of 301 W kg^-1. These findings shine a light on the rational design of electrode materials with multicomponents for high-performance supercapacitors.

Ellagic acid solid dispersion: Characterization and bioactivity in the hydroxyl radical oxidation system

Ellagic acid solid dispersion (EASD) was prepared using polyvinylpyrrolidone (PVP) as a carrier to improve its solubility. The solubility of EASD enhanced to 0.593 mg/mL, more than 20 times of the solubility on pure EA. The structure of EASD was analyzed by UV-visible spectroscopy, Fourier transforms infrared spectrometer (FT-IR) and X-ray diffraction (XRD), and results indicated the successful preparation of EASD, with a decrease in crystallinity. Differential scanning calorimetry (DSC) spectrums showed a lower endothermic peak of EASD than EA. By antioxidant analysis, the EASD with the concentration of 3 mg/mL was used in the protein oxidation analysis in hydroxyl radical oxidation simulation system, which was established by the myofibrillar of hairtail. EASD exhibited an excellent inhibit effect on protein oxidation. By increasing the solubility, EASD broadens the application range of EA, providing a theoretical basis for its application in the preservation of aquatic products.

Multi-amine-assisted crystal growth of large-sized α-MoO3 elongated nano-plates

Large-sized α-MoO₃ elongated nano-plates were synthesized by the introduction of multi-amines such as ethylene di-amine and diethylene tri-amine (DETA) in the conventional hydrothermal reaction. DETA made large hexagonal rods with an h-MoO₃ intermediate phase containing H₂O, NH₄OH, and DETA ions. During the hydrothermal reaction, the hexagonal rods were transformed to elongated α-MoO₃ nano-plates by the re-dissolution of h-MoO₃ and re-growth to α-MoO₃ because DETA retarded the preferred growth reaction of the MoO₆ octahedra to the [001] direction and helped the MoO₆ octahedra to grow in the [100] direction. In addition, DETA promoted α-MoO₃ nano-belts to be assembled into elongated nano-plates by oriented attachment because the multi-ammonium groups in the DETA backbone could adhere to the α-MoO₃ nano-belts due to attractive Coulomb interactions.

Nanostructured Fe,Co-Codoped MoO₃ Thin Films

Molybdenum oxide (MoO₃) and Fe,Co-codoped MoO₃ thin films obtained by spray pyrolysis have been in-depth investigated to understand the effect of Co and Fe codoping on MoO₃ thin films. The effect of Fe and Co on the structural, morphological and optical properties of MoO₃ thin films have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray analysis (EDAX), optical and photoluminescence (PL) spectroscopy, and electropyroelectric methods. The XRD patterns demonstrated the formation of orthorhombic α-MoO₃ by spray pyrolysis. SEM characterization has shown an increase in roughness of MoO₃ thin films by Fe and Co doping. Optical reflectance and transmittance measurements have shown an increase in optical band gap with the increase in Fe and Co contents. Thermal conductivity and thermal diffusivity of Fe,Co-doped MoO₃ were 24.10–25.86 Wm⁻¹K⁻¹ and 3.80 × 10⁻⁶–5.15 × 10⁻⁶ m²s⁻¹, respectively. MoO₃ thin films have shown PL emission. Doping MoO₃ with Fe and Co increases emission in the visible range due to an increase number of chemisorbed oxygen atoms. The photodegradation of an aqueous solution of methylene blue (MB) depended on the content of the codoping elements (Fe,Co). The results showed that a degradation efficiency of 90% was observed after 60 min for MoO₃: Fe 2%-Co 1%, while the degradation efficiency was about 35% for the undoped MoO₃ thin film.

Flame Spray Synthesis and Ammonia Sensing Properties of Pure α-MoO3 Nanosheets

This paper highlights the flame spray synthesis of α-MoO3 using ammonium molybdate as precursor. The as-synthesized particles obtained were found to be ammonium molybdenum oxide and belonged to the triclinic crystal system. The particles crystallized to α-MoO3 upon thermal treatment at 500°C. Sensors were prepared by drop coating the powders onto alumina substrates coated with platinum electrodes and sensing tests were conducted evaluating the detection of ammonia concentrations down to ppb level concentration in air. The flame synthesized α-MoO3 based sensors show high sensitivity towards ammonia and may potentially be used in breath ammonia gas diagnostics.

Fe2(MoO4)3 nanoparticle-anchored MoO3 nanowires: strong coupling via the reverse diffusion of heteroatoms and largely enhanced lithium storage properties

Fe₂(MoO₄)₃ nanoparticle-anchored MoO₃ nanowires via strong coupling via the reverse diffusion of heteroatoms and largely enhanced lithium-storage properties due to the synergistic effect of Fe₂(MoO₄)₃ nanoparticles and MoO₃ nanowires.

Preparation of h-MoO3 and α-MoO3 nanocrystals: comparative study on photocatalytic degradation of methylene blue under visible light irradiation

A detailed study on visible light photocatalytic degradation of methylene blue (MB) has been investigated in aqueous heterogeneous media containing hexagonal phase molybdenum oxide (h-MoO3) nanocrystals (NCs) which was identified as a new material for visible light driven photocatalysis. A simple and template-free solution based chemical precipitation method was employed to synthesize h-MoO3 NCs by reacting ammonium heptamolybdate tetrahydrate (AHM) with nitric acid. The formation and growth mechanism of h-MoO3 microstructures was explained. In addition, by annealing the h-MoO3 sample, the phase stability of hexagonal was retained up to 410 °C and showed an irreversible phase transition from hexagonal (h-MoO3) to highly stable orthorhombic phase (α-MoO3). Finally, the photocatalytic activities of h-MoO3 and α-MoO3 samples were evaluated using the degradation of MB, representing an organic pollutant of dye wastewater. The effects of various experimental parameters such as catalyst loading, initial dye concentration, light intensity, and operating temperature were analyzed for the degradation of MB. The results demonstrated that the efficiency of visible light assisted MB degradation using h-MoO3 NCs can be effectively enhanced by catalyst loading, light intensity, and operating temperature. However, the efficiency declined with the increase in initial dye concentration. Optimum conditions for higher photocatalytic performance were recognized as a catalyst loading of 100 mg L(-1), a dye concentration of 12 mg L(-1), a light intensity of 350 mW cm(-2), and an operating temperature of 45 °C.

Investigation on structural, thermal, optical and sensing properties of meta-stable hexagonal MoO(3) nanocrystals of one dimensional structure

Hexagonal molybdenum oxide (h-MoO(3)) was synthesized by a solution based chemical precipitation technique. Analysis by X-ray diffraction (XRD) confirmed that the as-synthesized powder had a metastable hexagonal structure. The characteristic vibrational band of Mo-O was identified from Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images clearly depicted the morphology and size of h-MoO(3.) The morphology study showed that the product comprises one-dimensional (1D) hexagonal rods. From the electron energy loss spectroscopy (EELS) measurement, the elemental composition was investigated and confirmed from the characteristic peaks of molybdenum and oxygen. Thermogravimetric (TG) analysis on metastable MoO(3) revealed that the hexagonal phase was stable up to 430 °C and above this temperature complete transformation into a highly stable orthorhombic phase was achieved. The optical band gap energy was estimated from the Kubelka-Munk (K-M) function and was found to be 2.99 eV. Finally, the ethanol vapor-sensing behavior was investigated and the sensing response was found to vary linearly as a function of ethanol concentration in the parts per million (ppm) range.