MoO3 Nanoparticles Research Articles

Bimetallic oxide nanoparticles contained hollow spheres with sodium as a core: a promising energy storage advanced structure

The bimetallic oxide nanoparticles as outer shell with sodium entrapped as a core part of a hollow porous core–shell (HoPoCs) can be a promising battery electrode composition. Till now, scientists are struggling to synthesize ternary metal oxide hollow spheres due to the reactions between diverse cations and anions of different metal precursors. Also, the extremely reactive character of sodium prevents it from remaining alone without compound formation is unveiled. Here for the first time, we entrapped sodium and synthesized bimetallic nanoparticles contained outer shell hollowsphere (Na@ZnO@MoO2) successfully by sorption (absorption + adsorption) of two metal precursors (sodium molybdate dihydrate and zinc chloride) in two steps without adding any reaction inhibiting agent. As a result, significantly Na is entrapped as a core and ZnO and MoO2 nanoparticles forming the outer shell of the sphere. ‘Na’ entrapment is confirmed by X-ray photoelectron spectroscopy and high-angle annular dark-field scanning transmission electron microscopy elemental mapping. We employed our sodium entrapped HoPoCs bimetallic oxide nanoparticles sphere (Na@ZnO@MoO2) as a battery anode getting advantages from their structural specialty shows excellent battery properties promising for application in energy storage technologies. The initial specific capacity of these HoPoCs-Na@ZnO@MoO2 sphere is 940 mAh/g (1C), with exceptional stability (790 mAh/g) after 1000 cycles at a current density of 2C) and excellent rate capability. This approach will motivate the synthesis of other superior reactive element entrapped core–shell metal oxides for next-generation rechargeable batteries and other advanced suitable applications like microreactor, protector of explosive materials, and so on.

Strongly surface-bonded MoO2 and N-doped hierarchical carbon nanoplates through interfacial Mo-N-C bonds with superb room/low-temperature Li-storage performance

The sluggish ionic migration kinetics and fragile electrode/electrolyte interface bear the primary responsibility for the poor electrochemical performances of the subzero-temperature electrodes for lithium-ion batteries. To surmount these challenges, strongly surface-bonded MoO2 and N-doped hierarchical carbon nanoplates (s-MoO2/N-C) through interfacial Mo-N-C bonds were rationally designed and controllably fabricated by a self-template strategy. In the target sample, the MoO2 nanoparticles wrapped by uniform N-doped carbon films (N-C) are well decorated on a layered carbon matrix, forming a unique shale-like structure. Particularly, the Mo-N-C bonds endow the s-MoO2/N-C with enhanced charge transfer capability and robust electrode/electrolyte interface, thus fast surface-controlled Li-storage kinetics are observed in s-MoO2/N-C. Due to these structural merits, the as-synthesised s-MoO2/N-C demonstrates superb room/low-temperature Li-storage performances. For instance, the reversible capacity of s-MoO2/N-C can reach up to 660.8 mAh g−1 in the 1000th cycle at 1.0 A g−1 at room temperature. Furthermore, such an s-MoO2/N-C electrode also attains high capacities of 703.2, 590.3, 454.8, and 305.2 mAh g−1 at low temperatures of 5, − 10, − 20, and even − 30 °C, respectively.

Improving Lithium Storage Properties of SiOx Nanosheets By Introducing MoO2 Nanoparticles

Silicon oxides (SiOx) have been recognized as promising candidates to replace commercial graphite anode materials in lithium-ion batteries. Two-dimensional (2D) microstructure of SiOx nanosheets leads to high capacity retention with the excellent dimensional stability. However, they have the disadvantage of having low specific capacity and low initial Coulombic efficiency. Here, molybdenum dioxide (MoO2) nanoparticles were introduced to compensate for the shortcomings of SiOx nanosheets. MoO2 nanoparticles are chemically bonded to the surface of SiOx nanosheets by Mo-O-Si bond, as a result, showing the improved reversible capacity and initial Coulombic efficiency while maintaining the strength of SiOx nanosheets. The observed improvement can be explained by the synergistic effect resulted by the combination of SiOx nanosheets with zero-dimensional (0D) MoO2 nanoparticles. The former provides favorable microstructures and dimensional stability while the latter offers abnormal lithium storage sites and highly reversible phase transition. In the presentation, the improved lithium storage properties of 2D-SiOx/0D-MoO2 nanocomposites will be discussed in detail.

Ultra-low core loss FeSiAl-based soft magnetic composites with ultra-thin MoO3 composite insulating layer

In this work, core/shell structured FeSiAl/MoO3 (spherical FeSiAl covered by ultra-thin MoO3 composite insulating layer) soft magnetic composites (SMCs) have been fabricated by a two-step heat treatment process. The influences of ammonium molybdate (AHM) content, first-step annealing temperature and second-step annealing temperature on magnetic, mechanical properties and electrical resistivity (ρ) have been comprehensively investigated. It is shown that the coating integrity and the thickness of MoO3 nanoparticles layer can be regulated by the content of AHM, leading to the improvement of ρ. Moreover, composite insulating layer with the thickness of 47 ± 8 nm is formed and completely coated on FeSiAl particles with 15 wt% AHM, resulting in the fact that the highest radial crushing strength (K = 62.3 MPa) and lowest core loss (Pcv = 128.8 mW/cm3) is obtained. In addition, Pcv is separated into two components: hysteresis loss component and eddy current loss component. Further studies display that eddy current loss is only half of hysteresis loss. As a result, the FeSiAl SMCs with 47 ± 8 nm MoO3 composite insulating layer possess the lowest core loss of 128.8 mW/cm3 at 50 mT/100 kHz. The low core loss of the FeSiAl/MoO3 SMCs with ultra-thin composite insulating layer has a great potential in the fields of conversion and power transmission.

Acid recovery from molybdenum metallurgical wastewater via selective electrodialysis and nanofiltration

The molybdenum mining industry discharges a large volume of acidic wastewater containing significant amounts of molybdenum, copper, and other non-valuable metals. In this study, the separation of metal ions (Mo6+, Fe2+, Ca2+, Na+) and recovery of sulfuric acid from molybdenum metallurgical wastewater were investigated via selective electrodialysis (SED) and nanofiltration (NF). A constant voltage of 6 V and volume ratio between the diluent and concentrate chamber of 1:1 was optimized for SED with a highest acid recovery of 89.6% and Mo6+ rejection rate of 98.1%. In contrast, an optimized operating pressure of 1.0 MPa led to highest acid recovery rate of 59.1% and Mo6+ rejection rate of 96.3% in the NF process. The comparison between SED and NF suggests that SED is more competitive than NF for this wastewater treatment with less energy consumption, higher acid recovery rate and higher purity for the recovered acid. Furthermore, coupling NF with SED could reach an acid recovery rate of over 94.2%. Moreover, it was feasible to convert the residual solution of the membrane process into MoO3 nanoparticles by post-treatment. Therefore, it could be concluded that SED and NF are both promising technologies for acid recovery from molybdenum metallurgical wastewater.

MoO2 Nanoparticles Decorated MoS2 Nansheets Encapsulated on MXene as Advanced Anode for Ultrafast and Stable Lithium Ion Batteries

MoO2 Nanoparticles Decorated MoS2 Nansheets Encapsulated on MXene as Advanced Anode for Ultrafast and Stable Lithium Ion Batteries

Applications of molybdenum oxide nanoparticles impregnated collagen scaffolds in wound therapeutics

IntroductionThe highly complex pathophysiology of the wound micro-environment demands the development of a multi-faceted system which would enhance the wound healing cascade. Incorporation of nanotechnology in wound therapeutics has opened up new avenues to tourment the diseased condition. Amongst the various types of nanoparticles molybdenum oxide nanoparticles posses various inherent properties that makes it a versatile material to be used in healing. Incorporation of Molybdenum nanoparticles into collagen scaffolds would provide a synergistic and sequential healing process ensuring the formation of a fully functional tissue. Materials and methodsThe physico-chemical characterization of the synthesized materials were done using SEM and FT-IR techniques. The bicompatibility and cell proliferation were tested using HaCaT cell lines. Pro-angiogenic ability of the scaffold was tested using CAM assay and Chick aortic arch assay. Finally the in-vivo wound healing ability of the material was tested by creating wound of about 6 cm2 on the dorsal side of Wistar rats and observed for about 21 days. ResultsThe characterization of the scaffold revealed the presence MoO3 nanoparticles and their structural integrity within the scaffold. The synthesized MoO3-collagen nanocomposite was found to be biocompatible and hemocompatible. The in-vitro studies demonstrated that the MoO3-collagen scaffold significantly increased the cell adhesion and migration to nearly 2 fold. The MoO3 embedded collagen sheets synergistically favoured neovascularization and re-epithelization,which would potentially enhance therapeutic efficiency of the scaffold. The nanocomposite also encouraged results in in-vivo analysis, the Wistar rats treated with MoO3-collagen scaffolds showed complete healing in about 15 days. ConclusionThe fabricated MoO3-collagen scaffold was found to play an important role in all major events of wound healing such as adhesion, migration, proliferation and angiogenesis. The in-vivo healing assay also proved that the healing rate of animals treated with the samples was comparatively faster. Further research using various trace elements would open up promising avenues in healing therapeutics

Design and fabrication of MoO3 nanoparticles incorporated PEDOT:PSS hybrid thin films for ITO-free organic solar cells

Design and fabrication of MoO3 nanoparticles incorporated PEDOT:PSS hybrid thin films for ITO-free organic solar cells

Oxidative desulfurization of a model fuel using MoO3 nanoparticles supported on carbon nanotubes catalyst: Examine most significance variables, optimization, kinetics and thermodynamics study

Molybdenum oxide nanoparticles MONP were dispersed on multiwall nanotubes MWNTs as an attempt to synthesize MONP/MWNTs catalyst, the synthesis method done by wet impregnation. The prepared catalyst was characterized by FTIR (Fourier –Transform Infrared Spectroscopy) and, XRD (X-ray diffraction), whilst the catalyst activity is done with catalytic oxidative desulfurization ODS reaction for oxidation dibenzothiophene DBT dissolved in heptane (model fuel) with hydrogen peroxide H2O2, in which catalyst activity investigation achieved via studying impact six from most affected variables on ODS reaction. The chosen variables are reaction temperature, contact time, sulfur initial sulfur concentration, stirring speed, oxidant/sulfur ratio and catalyst dosage, and then the studied variables were screened by application of Plackett-Burman design PBD to identify the more significant on response (DBT pollutant removal). DBT pollutant removal is referred to as sulfur removal efficiency. Analysis of variance ANOVA shows that the reaction temperature, oxidant/sulfur ratio, stirring speed, and sulfur initial concentration are the most significant from the chosen variables due to their F-values 37.60, 25.45, 11.62 and 6.71 respectively. Box –Behnken experimental design was used to complete the study the effect of the most significant more deeply on ODS reaction (sulfur removal efficiency),in which this part exhibited that sulfur removal efficiency at range between 51 and 93%, whilst the optimum sulfur removal efficiency was 96% at 70 °C,4.36, 957 rpm and 50 ppm for reaction temperature, oxidant/sulfur ration, stirring speed and initial sulfur concentration respectively. The study involves estimation of kinetics and thermodynamics parameters for ODS reaction; kinetics studying exhibited that ODS reaction followed pseudo-first-order reaction with activation energy (12.996 kJ/mol), while the thermodynamics study shows the low negative entropy change (-0.221 kJ /mol.K), positive enthalpy and free energy changes which confirm a high hydrate transition complex was formed.

A sensitive colori/fluorimetric nanoprobe for detection of polyphenols using peroxidase-mimic plasma-modified MoO3 nanoparticles

Herein, MoO3 nanoparticles were synthesized and modified using Argon cold plasma treatment (Ar-MoO3NPs) for the first time. Various characterization studies were performed using various methods, including SEM, XRD, and FTIR techniques. The catalytic activity of MoO3NPs before and after modification was investigated using fluorometric and colorimetric experiments. The results indicated that the enzyme-mimic activity of MoO3NPs increased after plasma-surface modification (1.5 fold). Also, a fluorometric method based on the oxidation of a non-fluorescent terephthalic acid by Ar-MoO3NPs in the presence of H2O2 and the production of a compound with a high emission was designed for polyphenols detection. Quercetin was used as a polyphenol standard for the optimization of the proposed system. Under the optimum conditions, the dynamic ranges of the calibration graphs and the detection limits were calculated for different polyphenols (μmol/L): quercetin (2–232, 12.22), resveratrol (2–270, 61.89), curcumin (39–400, 38.89), gallic acid (2–309, 21.5) and ellagic acid (39–309, 16.25). Also, the precision of the method, which was expressed as RSD%, was in the range of 0.286–1.19%. The proposed system could detect individual polyphenols and total polyphenols in three different fruit extracts (apple, orange, and grapes) with high sensitivity. The obtained total concentrations of polyphenols in real samples were comparable to those calculated by the spectrophotometric method. So, a novel and sensitive optical nanosensor for the detection of polyphenols was reported as an alternative to the routine Folin-Ciocalteu spectrophotometric technique.

Green fluorescent carbon dots functionalized MoO3 nanoparticles for sensing of hypochlorite

In this study, three different colored blue (B-), green (G-) and yellow (Y-) fluorescent carbon dots (CDs) were synthesized by using natural precursor Annona squamosa fruit via acid oxidation method. The as-synthesized B-, G- and Y-CDs displayed intense emission peaks at 445, 514 and 558 nm upon the excitations at 360, 420 and 440 nm, respectively. The functionalization of molybdenum oxide nanoparticles (MoO3 NPs) with three color emissive CDs allows well dispersability in aqueous media and converts the non-fluorescent nature of MoO3 NPs to blue, green and yellow color emissions, which is beneficial for the sensitive assay of hypochlorite (ClO-). It was found that the emission intensity of G-CDs functionalized MoO3 NPs at 516 nm was remarkably quenched by ClO-, whereas ClO- showed least quenching ability towards blue- and yellow- MoO3 NPs. Based on these observations, MoO3 NPs-G-CDs showed a linear fluorescence quenching at 516 nm in the range of 0.010–200 µM with detection limit of 6.8 nM for ClO-. The developed optical sensor affords good selectivity for the detection of ClO- in water samples with good recoveries, which demonstrates great promise of MoO3 NPs-G-CDs in assaying ClO- in complex samples at minimal volume of samples.

MoO3 Nanoparticle Coatings on High-Voltage 5 V LiNi0.5Mn1.5O4 Cathode Materials for Improving Lithium-Ion Battery Performance.

To reduce surface contamination and increase battery life, MoO3 nanoparticles were coated with a high-voltage (5 V) LiNi0.5Mn1.5O4 cathode material by in-situ method during the high-temperature annealing process. To avoid charging by more than 5 V, we also developed a system based on anode-limited full-cell with a negative/positive electrode (N/P) ratio of 0.9. The pristine LiNi0.5Mn1.5O4 was initially prepared by high-energy ball-mill with a solid-state reaction, followed by a precipitation reaction with a molybdenum precursor for the MoO3 coating. The typical structural and electrochemical behaviors of the materials were clearly investigated and reported. The results revealed that a sample of 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode exhibited an optimal electrochemical activity, indicating that the MoO3 nanoparticle coating layers considerably enhanced the high-rate charge–discharge profiles and cycle life performance of LiNi0.5Mn1.5O4 with a negligible capacity decay. The 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode could achieve high specific discharge capacities of 131 and 124 mAh g−1 at the rates of 1 and 10 C, respectively. In particular, the 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode retained its specific capacity (87 mAh g−1) of 80.1% after 500 cycles at a rate of 10 C. The Li4Ti5O12/LiNi0.5Mn1.5O4 full cell based on the electrochemical-cell (EL-cell) configuration was successfully assembled and tested, exhibiting excellent cycling retention of 93.4% at a 1 C rate for 100 cycles. The results suggest that the MoO3 nano-coating layer could effectively reduce side reactions at the interface of the LiNi0.5Mn1.5O4 cathode and the electrolyte, thus improving the electrochemical performance of the battery system.

Fully Scalable and Stable CsPbI2Br Solar Cells Realized by an All-Spray-Coating Process.

Spray-coating is a scalable and time-efficient technique for the development of large-area metal halide perovskite (MHP) solar cells. However, a bottleneck still exists toward the development of fully scalable n-i-p-type MHP solar cells particularly on spray-coating the hole transporting layer (HTL). Here, we present a reliable strategy of spray-coating the HTL by using MoO2 nanoparticles with small amounts of poly(triarylamine) (PTAA) binders to ensure uniform coverage and efficient charge extraction. By spray-coating all layers except the Au electrode, we achieve high and scalable efficiencies of 14.26 and 13.88% for CsPbI2Br unit cells (0.12 cm2) and submodules (25 cm2), respectively. We then extend toward an all-spray-coating process by spray-coating carbon black as the top counter electrode, resulting in a submodule efficiency of 10.08%. Finally, we also demonstrate good long-term stability of the submodules under damp heat conditions (85 °C/85% relative humidity) over 1000 h.

Constructing zigzag-like hollow mesoporous nanospheres MoO2/C with superior lithium storage performance

Hollow mesoporous nanospheres MoO2/C are successfully constructed through metal chelating reaction between molybdenum acetylacetone and glycerol as well as the Kirkendall effect induced by diammonium hydrogen phosphate. MoO2 nanoparticles coupled by amorphous carbon are assembled to unique zigzag-like hollow mesoporous nanosphere with large specific surface area of 147.7 m2 g−1 and main pore size of 8.7 nm. The content of carbon is 9.1%. As anode material for lithium-ion batteries, the composite shows high specific capacity and excellent cycling performance. At 0.2 A g−1, average discharge capacity stabilizes at 1092 mAh g−1. At 1 A g−1 after 700 cycles, the discharge capacity still reaches 512 mAh g−1. Impressively, the composite preserves intact after 700 cycles. Even at 5 A g−1, the discharge capacity can reach 321 mAh g−1, exhibiting superior rate capability. Various kinetics analyses demonstrate that in electrochemical reaction, the proportion of the surface capacitive effect is higher, and the composite has relatively high diffusion coefficient of Li ions and fast faradic reaction kinetics. Excellent lithium storge performance is attributed to the synergistic effect of zigzag-like hollow mesoporous nanosphere and amorphous carbon, which improves reaction kinetics, structure stability and electronic conductivity of MoO2. The present work provides a new useful structure design strategy for advanced energy storage application of MoO2.

Electrochemical activity of ultrathin MoO3 nanoflakes for long cycle lithium ion batteries

Solution based combustion method synthesis of porous MoO3 nanoparticles in one step by using ammonium heptamolybdate pentahydrate as a precursor with novel areca seed powder as green fuel. The analytical techniques like PXRD, FTIR, SEM, HRTEM, SAED were recorded in order to detect morphology, structure and composition of synthesised material. The obtained average crystalline size from XRD analysis was found to be 20 nm with TEM analysis of particle size ranging from 2 to 10 nm. As prepared material shows high specific capacity of 980 mAhg−1 and excellent run of about 400 cycles with extraordinary cycling performance of 652 mAhg−1 after 200 cycles including enhanced rate capability of 564mAhg−1 even at high current rate and thereby proving the auspicious anode material for lithium ion batteries.

Facile green synthesis of Molybdenum oxide nanoparticles using Centella Asiatica plant: Its photocatalytic and electrochemical lead sensor applications

The molybdenum oxide nanoparticles (MoO3 NPs) have been successfully synthesized via green combustion method using Centella asiatica plant powder. The powder x-ray diffraction (PXRD), Fourier transform infrared spectroscopic (FTIR), scanning electron microscopic (SEM) and diffuse reflectance spectroscopic (DRS) techniques were used to characterize the MoO3 nanoparticles. The PXRD patterns of the sample revealed pure hexagonal phase. The Scherrer's method was employed to find the crystallite size of the synthesized material and the result obtained was confirmed by the TEM analysis. The optical energy band gap value (Eg) of the sample was calculated using the Tauc relation, and it was found to be around 3.41 ​eV. The photocatalytic degradation of MoO3 NPs on Direct Green (DG) and Navy Blue (NB) dye was evaluated under UV light irradiation. The electrochemical study of prepared electrode with graphite powder in 0.1 ​M KOH electrolyte solution displayed superior redox potential output as intended by cyclic voltammetric and amperometric studies, where the material was employed for its sensing abilities such as a highly toxic metal like lead.

Rapid and flexible segmentation of electron microscopy data using few-shot machine learning

Automatic segmentation of key microstructural features in atomic-scale electron microscope images is critical to improved understanding of structure–property relationships in many important materials and chemical systems. However, the present paradigm involves time-intensive manual analysis that is inherently biased, error-prone, and unable to accommodate the large volumes of data produced by modern instrumentation. While more automated approaches have been proposed, many are not robust to a high variety of data, and do not generalize well to diverse microstructural features and material systems. Here, we present a flexible, semi-supervised few-shot machine learning approach for segmentation of scanning transmission electron microscopy images of three oxide material systems: (1) epitaxial heterostructures of SrTiO3/Ge, (2) La0.8Sr0.2FeO3 thin films, and (3) MoO3 nanoparticles. We demonstrate that the few-shot learning method is more robust against noise, more reconfigurable, and requires less data than conventional image analysis methods. This approach can enable rapid image classification and microstructural feature mapping needed for emerging high-throughput characterization and autonomous microscope platforms.

Spherical MoO3 Nanoparticles for Photocatalytic Removal of Eriochrome Black T

Spherical MoO₃ Nanoparticles for Photocatalytic Removal of Eriochrome Black T

Mesoporous MoO2-carbon nanocomposites synthesized by triconstituent co-assembly approach for high performance lithium-ion batteries

Molybdenum oxide (MoO2) has been considered as a promising anode material in lithium-ion batteries with high theoretical capacity (838 mAh/g); regrettably, the drawback of rapid capacity decay seriously hinders its application. In this work, MoO2 nanoparticles were in situ encapsulated inside the frameworks of porous carbon to construct MoO2-carbon nanocomposites by a facile triconstituent co-assembly approach. The obtained MoO2-carbon nanocomposites present stable structures and exhibit improved electrochemical performances of high reversible capacity (803 mAh/g at 0.1 A/g) and excellent cycling stability (572 mAh/g at 1 A/g after 400 cycles) as anode materials for lithium-ion batteries. These satisfactory results are mainly attributed to the synergy effects between the MoO2 nanoparticles and carbon frameworks, specifically a better accommodation of volume change and a shorter pathway for ion transmission.

Low-temperature hydrolysis of carbonyl sulfide in blast furnace gas using Al2O3-based catalysts with high oxidation resistance

Water vapor, O2 and various sulfides in blast furnace gases affect the carbonyl sulfide (COS) hydrolysis reaction. In this study, we investigated the hydrolysis and deactivation mechanisms of a series of catalysts that were synthesized by depositing K2O and MoO3 on industrial alumina-based catalysts. Alumina nanosheets were deposited with potassium oxide, in which MoO3 nanoparticles were incorporated resulting in needle-like structures. The modified catalysts had substantially enhanced COS hydrolysis activity at low temperatures. The introduction of K2O and MoO3 significantly increased the number of weakly basic sites on the catalysts and reduced the lattice oxygen content. The catalysts exhibited high oxidation resistance and hydrolysis properties. According to the poisoning mechanism, the deposition of sulfate species tended to reduce weakly basic sites. High-valent Mo easily excited the adsorbed H2O on the catalysts, producing –OH groups that facilitated the COS hydrolysis reaction. This modification facilitates the further investigation of catalysts capable of promoting COS hydrolysis and their application in the manufacturing industry.