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3,059 result(s) for "Tungsten oxide"
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Niobium tungsten oxides for high-rate lithium-ion energy storage
The maximum power output and minimum charging time of a lithium-ion battery depend on both ionic and electronic transport. Ionic diffusion within the electrochemically active particles generally represents a fundamental limitation to the rate at which a battery can be charged and discharged. To compensate for the relatively slow solid-state ionic diffusion and to enable high power and rapid charging, the active particles are frequently reduced to nanometre dimensions, to the detriment of volumetric packing density, cost, stability and sustainability. As an alternative to nanoscaling, here we show that two complex niobium tungsten oxides—Nb 16 W 5 O 55 and Nb 18 W 16 O 93 , which adopt crystallographic shear and bronze-like structures, respectively—can intercalate large quantities of lithium at high rates, even when the sizes of the niobium tungsten oxide particles are of the order of micrometres. Measurements of lithium-ion diffusion coefficients in both structures reveal room-temperature values that are several orders of magnitude higher than those in typical electrode materials such as Li 4 Ti 5 O 12 and LiMn 2 O 4 . Multielectron redox, buffered volume expansion, topologically frustrated niobium/tungsten polyhedral arrangements and rapid solid-state lithium transport lead to extremely high volumetric capacities and rate performance. Unconventional materials and mechanisms that enable lithiation of micrometre-sized particles in minutes have implications for high-power applications, fast-charging devices, all-solid-state energy storage systems, electrode design and material discovery. Micrometre-sized particles of two niobium tungsten oxides have high volumetric capacities and rate performances, enabled by very high lithium-ion diffusion coefficients.
Classification of Nanomaterials and the Effect of Graphene Oxide (GO) and Recently Developed Nanoparticles on the Ultrafiltration Membrane and Their Applications: A Review
The emergence of mixed matrix membranes (MMMs) or nanocomposite membranes embedded with inorganic nanoparticles (NPs) has opened up a possibility for developing different polymeric membranes with improved physicochemical properties, mechanical properties and performance for resolving environmental and energy-effective water purification. This paper presents an overview of the effects of different hydrophilic nanomaterials, including mineral nanomaterials (e.g., silicon dioxide (SiO2) and zeolite), metals oxide (e.g., copper oxide (CuO), zirconium dioxide (ZrO2), zinc oxide (ZnO), antimony tin oxide (ATO), iron (III) oxide (Fe2O3) and tungsten oxide (WOX)), two-dimensional transition (e.g., MXene), metal–organic framework (MOFs), covalent organic frameworks (COFs) and carbon-based nanomaterials (such as carbon nanotubes and graphene oxide (GO)). The influence of these nanoparticles on the surface and structural changes in the membrane is thoroughly discussed, in addition to the performance efficiency and antifouling resistance of the developed membranes. Recently, GO has shown a considerable capacity in wastewater treatment. This is due to its nanometer-sized holes, ultrathin layer and light and sturdy nature. Therefore, we discuss the effect of the addition of hydrophilic GO in neat form or hyper with other nanoparticles on the properties of different polymeric membranes. A hybrid composite of various NPs has a distinctive style and high-quality products can be designed to allow membrane technology to grow and develop. Hybrid composite NPs could be used on a large scale in the future due to their superior mechanical qualities. A summary and future prospects are offered based on the current discoveries in the field of mixed matrix membranes. This review presents the current progress of mixed matrix membranes, the challenges that affect membrane performance and recent applications for wastewater treatment systems.
Insights into structure, toxicity and antibacterial potential of tungsten oxide–carbon nanocomposites coupled with antibiotics
The Houbara bustard is a vulnerable bird species that often experiences higher morbidity and mortality due to infections caused by the multiple drug-resistant pathogens like Salmonella . Studies exploring alternative therapeutics are essential to strengthen antimicrobial stewardship. This study evaluated the antibacterial potential and toxicity of a tungsten oxide nanocomposite (WO 3 /C 3 N 4 , WNC) combined with antibiotics against multidrug-resistant (MDR) Salmonella enterica strains isolated from Houbara bustards. Preparations used in this study included WNC alone and in combination with ciprofloxacin, penicillin, ampicillin, and oxytetracycline. Characterization of WNC through FTIR showed absorption at 799 cm −1 , indicating W–O–W stretching and confirming WO 3 integration while the particle sizes, as identified through SEM, ranged from 20 to 300 nm. The XRD patterns showed fewer sharp peaks for the WNC, confirming its crystalline nature. The antibacterial potential of these products revealed lowest MICs in case of WNC + ciprofloxacin (16.74 ± 4.76 µg/mL) and WNC + oxytetracycline (30.69 ± 10.44 µg/mL), while WNC alone and with penicillin or ampicillin exceeded 100 µg/mL. The toxicity assay showed the WNC + ampicillin significantly reducing mitotic and phase indices in a dose-dependent manner ( p  < 0.05) at 24 and 48 h. All treatments showed significant ( p  ≤ 0.05) dose-dependent genotoxic effects. The study concluded that WNC-antibiotic combinations are effective against MDR Salmonella and relatively safe for host systems, supporting their potential as alternative antibacterial agents.
Point-of-care diagnostics for rapid determination of prostate cancer biomarker sarcosine: application of disposable potentiometric sensor based on oxide-conductive polymer nanocomposite
One of the most important reasons for an increased mortality rate of cancer is late diagnosis. Point-of-care (POC) diagnostic sensors can provide rapid and cost-effective diagnosis and monitoring of cancer biomarkers. Portable, disposable, and sensitive sarcosine solid-contact ion-selective potentiometric sensors (SC-ISEs) were fabricated as POC analyzers for the rapid determination of the prostate cancer biomarker sarcosine. Tungsten trioxide nanoparticles (WO3 NPs), polyaniline nanoparticles (PANI NPs), and PANI-WO3 nanocomposite were used as ion-to-electron transducers on screen-printed sensors. WO3 NPs and PANI-WO3 nanocomposite have not been investigated before as ion-to-electron transducer layers in potentiometric SC sensors. The designated sensors were characterized using SEM, XRD, FTIR, UV-VIS spectroscopy, and EIS. The inclusion of WO3 and PANI in SC sensors enhanced the transduction at the interface between the screen-printed SC and the ion-selective membrane, offering lower potential drift, a longer lifetime, shorter response time, and better sensitivity. The proposed sarcosine sensors exhibited Nernstian slopes over linear response ranges 10−3–10−7 M, 10−3–10−8 M, 10−5–10−9 M, and 10−7–10−12 M for control, WO3 NPs, PANI NPs, and PANI-WO3 nanocomposite-based sensors, respectively. From a comparative point of view between the four sensors, PANI-WO3 nanocomposite inclusion offered the lowest potential drift (0.5 mV h−1), the longest lifetime (4 months), and the best LOD (9.95 × 10−13 M). The proposed sensors were successfully applied to determine sarcosine as a potential prostate cancer biomarker in urine without prior sample treatment steps. The WHO ASSURED criteria for point-of-care diagnostics are met by the proposed sensors.
Structure and electrochromism of two-dimensional octahedral molecular sieve h’-WO3
Octahedral molecular sieves (OMS) are built of transition metal-oxygen octahedra that delimit sub-nanoscale cavities. Compared to other microporous solids, OMS exhibit larger versatility in properties, provided by various redox states and magnetic behaviors of transition metals. Hence, OMS offer opportunities in electrochemical energy harnessing devices, including batteries, electrochemical capacitors and electrochromic systems, provided two conditions are met: fast exchange of ions in the micropores and stability upon exchange. Here we unveil a novel OMS hexagonal polymorph of tungsten oxide called h’-WO 3 , built of (WO 6 ) 6 tunnel cavities. h’-WO 3 is prepared by a one-step soft chemistry aqueous route leading to the hydrogen bronze h’-H 0.07 WO 3 . Gentle heating results in h’-WO 3 with framework retention. The material exhibits an unusual combination of 1-dimensional crystal structure and 2-dimensional nanostructure that enhances and fastens proton (de)insertion for stable electrochromic devices. This discovery paves the way to a new family of mixed valence functional materials with tunable behaviors. Thanks to their versatile redox behaviors, octahedral molecular sieves show promise in a range of electrochemical applications. Here the authors report a hexagonal polymorph of tungsten trioxide, an octahedral molecular sieve that exhibits fast proton (de)insertion for electrochromic devices.
Multi-functional anodes boost the transient power and durability of proton exchange membrane fuel cells
Proton exchange membrane fuel cells have been regarded as the most promising candidate for fuel cell vehicles and tools. Their broader adaption, however, has been impeded by cost and lifetime. By integrating a thin layer of tungsten oxide within the anode, which serves as a rapid-response hydrogen reservoir, oxygen scavenger, sensor for power demand, and regulator for hydrogen-disassociation reaction, we herein report proton exchange membrane fuel cells with significantly enhanced power performance for transient operation and low humidified conditions, as well as improved durability against adverse operating conditions. Meanwhile, the enhanced power performance minimizes the use of auxiliary energy-storage systems and reduces costs. Scale fabrication of such devices can be readily achieved based on the current fabrication techniques with negligible extra expense. This work provides proton exchange membrane fuel cells with enhanced power performance, improved durability, prolonged lifetime, and reduced cost for automotive and other applications. Proton exchange membrane fuel cells often suffer from low lifetimes and high cost. Here, the authors enhance the transient power performance and durability of these fuel cells by integrating a thin layer of tungsten oxide within the anode, which acts as a hydrogen reservoir, oxygen scavenger, and a regulator for the hydrogen-disassociation reaction.
Facile preparation of amorphous carbon-coated tungsten trioxide containing oxygen vacancies as photocatalysts for dye degradation
In this work, a simple strategy to fabricate amorphous carbon-coated tungsten oxide with oxygen vacancies (WO3−x/C, 0 < x < 1) via pyrolysis of hybrid-polyoxometalates (hybrid-POMs) in nitrogen atmosphere is reported. TGA, XRD, Raman, FTIR, SEM, TEM, EDS, XPS and BET have been used to characterize the as-prepared products. The results showed that their compositions, microstructures and concentrations of oxygen vacancies were closely related with the species of organic amines in the hybrid-POMs. When the WO3−x/C composites were used as catalysts for degradation of dyes such as methylene blue, methyl orange and Rhodamine B under visible light irradiation, they showed much enhanced photocatalytic abilities compared to that of WO3 and P25, which could be ascribed to the coating of WO3 by amorphous carbon and the construction of defects (oxygen vacancy) in WO3. The synthetic strategy presented in our work is simple and shows a great potential in fabricating efficient transition metal-based composites for photocatalysis applications and so on.
Unraveling the role of MXene (Ti3C2Tx) integrated Cu-doped WO3 nanocomposites via co-precipitation technique for enhanced supercapacitor performance
The rising population and increased energy consumption drive contemporary researchers to develop highly efficient electrode materials for high-power energy storage devices. Herein, copper-doped tungsten oxide (Cu-WO 3 ) and compositing MXene (Cu-WO 3 /MXene) in different concentrations have garnered substantial interest for their usage as an electrode material owing to their impressive energy-storing capacity, including high metallic conductivity, hydrophilic nature, and exceptional electrochemical performance due to their active surface chemistry. In the present work, we employ a facile co-precipitation technique to fabricate WO 3 and Cu-WO 3 (Cu x% = 5 at%, 10 at%, and 15 at%). Furthermore, we synthesized a synergistic 15 at% Cu-WO 3 /MXene nanocomposite by integrating Cu-WO 3 and MXene via sonication. The synthesized sample’s structure, functional, morphology, chemical composition, and electrochemical properties were examined through various techniques such as X-ray powder diffraction (XRD), Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectra (XPS), Field Emission Scanning Electron Microscopy (FESEM), and High-Resolution Transmission Electron Microscopy (HRTEM). The X-ray diffraction analyses corroborated the monoclinic state of WO 3 along with the substitutional inclusion of Cu in the WO 3 lattice integrated with MXene. Utilizing a Field Emission Scanning Electron Microscope (FESEM), the surface morphological analysis revealed the formation of Cu-WO 3 nanospheres embedded in MXene sheets. Furthermore, according to results obtained from electrochemical analysis profiles, at 1 mA, 15 at% Cu-WO 3 /MXene displayed a greater specific capacitance of 692.4 F/g in comparison to other electrode materials via a three-electrode system, which is due to the synergistic impact of the Cu-WO 3 as well as the conductive properties of MXene sheets. Also, the electrode demonstrated excellent cycling stability, retaining 89% of its initial capacitance over 5000 charge-discharge cycles. The Ragone plot revealed an energy density of 70.10 Wh/kg at a power density of 809.8 W/kg. B-value analysis and scan rate-dependent CV confirmed the contribution of both surface-controlled and diffusion-controlled charge storage mechanisms. Likewise, in contrast to all other synthesized materials, 15 at% Cu-WO 3 /MXene revealed a lesser solution resistance and charge transfer resistance. In accordance with the results, the 15 at% Cu-WO 3 /MXene nanocomposite is an extremely efficient capacitive material that can enhance electrochemical performance in energy storage applications.
A Review on the Properties and Applications of WO3 Nanostructure−Based Optical and Electronic Devices
Tungsten oxide (WO3) is a wide band gap semiconductor with unintentionally n−doping performance, excellent conductivity, and high electron hall mobility, which is considered as a candidate material for application in optoelectronics. Several reviews on WO3 and its derivatives for various applications dealing with electrochemical, photoelectrochemical, hybrid photocatalysts, electrochemical energy storage, and gas sensors have appeared recently. Moreover, the nanostructured transition metal oxides have attracted considerable attention in the past decade because of their unique chemical, photochromic, and physical properties leading to numerous other potential applications. Owing to their distinctive photoluminescence (PL), electrochromic and electrical properties, WO3 nanostructure−based optical and electronic devices application have attracted a wide range of research interests. This review mainly focuses on the up−to−date progress in different advanced strategies from fundamental analysis to improve WO3 optoelectric, electrochromic, and photochromic properties in the development of tungsten oxide−based advanced devices for optical and electronic applications including photodetectors, light−emitting diodes (LED), PL properties, electrical properties, and optical information storage. This review on the prior findings of WO3−related optical and electrical devices, as well as concluding remarks and forecasts will help researchers to advance the field of optoelectric applications of nanostructured transition metal oxides.
Novel insights into acute/chronic genotoxic impact of exposure to tungsten oxide nanoparticles on Drosophila melanogaster
Tungsten oxide nanoparticles (WO3 NPs) have now been employed by various products including electronics, smart screens, gas-biosensors, water purifiers, disinfectants, and biomedical applications. Despite this wide-ranging adoption, little research has investigated their potential endpoint biomarkers in different in vivo models. We therefore propose the use of Drosophila melanogaster as a testing model in assessing genotoxic risks of exposure to WO3 NPs. Our study examined toxicity, phenotypic alterations, locomotor behavior (climbing assay), intracellular oxidative stress (ROS), DNA damage (Comet assay), and somatic recombination (wing spot assay) in Drosophila melanogaster after exposure to WO3 NPs (43.71 ± 1.59 nm) and microparticulated (MPs) of WO3. Drosophila larvae were exposed to the test materials via ingestion at doses ranging between 1 and 10 mM, and two greatest doses of NPs (5 and 10 mM) were found to cause mutagenic/recombinogenic effects, while the MPs caused no effects. Wing-spot assay detected genotoxic activity of NPs mostly through somatic recombination, and Comet assay showed DNA damage after exposure to NPs at certain doses (1, 2.5, 5, and 10 mM). Other observations included ROS generation in hemocytes, phenotypic alterations in the mouths and wings of adult flies, and impaired locomotor behavior. This is the first research to report genotoxic evidence on the impact of WO3 exposure in Drosophila larvae, highlighting the significance of this model organism in exploring the potential biological impact of nanoparticles and MPs of WO3. The results of our in vivo testing should make a vital contribution to the existing database on the genotoxicity of WO3 NPs.