Tungsten Oxide Nanostructures Research Articles

Controlled growth of YBCO film with tungsten oxide buffered substrate

This study explores the influence of tungsten oxide (WO3-x) nanostructures, decorated on LaAlO3 (LAO) single crystal substrate, on the fabrication and superconducting performance of YBa2Cu3Oy (YBCO) films. The WO3-x in square-dot and nanowire forms, significantly enhance the biaxial texture of YBCO films, resulting in high critical current density Jc (square-dot, 3.05 MA/cm2 @ 77 K, nanowire, 2.1 MA/cm2 @ 77 K). However, the presence of WO3-x nanodots leads to a random nucleation of YBCO grains along the a/b-axis, driving a porous surface and broadening the full width at half maximum (FWHM) in both phi and omega scans. This poor texture deteriorates the film’s Jc to 0.71 MA/cm2 @ 77 K. Therefore, optimizing the WO3-x interface is crucial for enhancing the epitaxial growth and critical current density of YBCO film. This study provides an effective approach to optimize the superconducting performance of YBCO film by tailoring nanostructure interface.

Synthesis and characterisation of Ag-Cu-co-Doped WO3 @Carbeneous materials composites for waste water treatment

Nanoparticles of tungsten oxide are widely used in advanced chemical processes but the application of tungsten oxide (WO3) in photocatalysis is limited. To increase their application in photocatalysis, nanostructured tungsten oxide (W-1) is co-doped with silver and copper (W-2), and nanocomposites with g-C3N4 (W-3) and CNTs (W-4) are synthesized. Structural, elemental, and morphological analyses of prepared samples were carried out using different characterization techniques like XRD, SEM, FTIR, EDX, and Mott-Schottky. The bandgap of WO3 is 2.75 eV which is reduced to 2.32 eV by doping and composite formation. The degradation of crystal violet and chlorpyrifos is done to check the photocatalytic performance of prepared materials under the light bulb energy. Photodegradation experiment shows 83.33 % and 41 % degradation of CV and chlorpyrifos respectively. The higher degradation ability is shown by CNTs composites because they have smaller crystallite size (12.81 nm) as compared to other photocatalysts. In the presence of CNTs, the rate of recombination of holes and electrons decreases, resulting in the enhancement of photocatalytic activity. The research reveals that W-4 exhibits promising potential for applications in the photodegradation of organic wastes.

Glutathione-Mediated Synthesis of WO3 Nanostructures with Controllable Morphology/Phase for Energy Storage, Photoconductivity, and Photocatalytic Applications.

Developing an improved synthesis method that controls the morphology and crystal phase remains a substantial challenge. Herein, we report phase and morphology-controlled hydrothermal synthesis of tungsten oxides by varying acid concentration and utilizing glutathione (GSH) as a structural directing agent, together with the exploration of their applications in supercapacitors, photoconductivity, and photocatalysis. Orthorhombic hydrated tungsten oxide (WO3·0.33H2O) with nonuniform block and plate-like morphology was obtained at 3 M hydrochloric acid (HCl). In contrast, nonhydrated monoclinic tungsten oxide (WO3) with smaller rectangular blocks was obtained at 6 M HCl. Further, the addition of GSH results in an increase in the surface area of the materials along with a narrowing of the band gap. Moreover, it plays a pivotal role in regulating the morphology through oriented attachments, Ostwald ripening, and the self-assembly of WO3 nuclei. GHTO and GTO polymorphs showed pseudocapacitive behavior with the highest specific capacitances of 450 and 300 F g-1 at 0.5 A g-1, maintaining 94 and 92% retention stability, respectively, over 1000 cycles at 2 A g-1. Also, the synthesized materials displayed favorable photoconductivity under light irradiation, implying potential utilization in photovoltaic applications. Moreover, these materials exhibited remarkable photocatalytic performance in the degradation of methylene blue (MB) dye, establishing themselves as highly effective photocatalysts. Therefore, nanostructured tungsten oxide showcases its versatility, rendering it an appealing candidate for energy storage, photovoltaic systems, and photocatalysis.

Porous Nanostructured Chromium-Doped Tungsten Oxide Electrocatalysts for Flutamide and Nilutamide Detection

Porous Nanostructured Chromium-Doped Tungsten Oxide Electrocatalysts for Flutamide and Nilutamide Detection

Is photoelectrocatalysis an efficient process to degrade endocrine disruptors chemicals?

Endocrine disruptors chemicals (EDCs) pose significant health risks, including cancer, behavioral disorders, and infertility. In this study, we employed the photoelectrocatalysis (PEC) technique with optimized tungsten oxide (WO3) nanostructures as a photoanode to degrade three diverse EDCs: methiocarb, dimethyl phthalate, and 4-tert-butylphenol. PEC degradation tests were carried out for individual contaminants and a mixture of them, assessing efficiency across different EDC families. Ultra High-Performance Liquid Chromatography and Mass Spectrometry was used to control the course of the experiments. For individual solutions, 4-tert-butylphenol and methiocarb were 100% degraded at 1 hour of PEC degradation. Among the tested EDCs, dimethyl phthalate showed the highest resistance to degradation when treated individually. However, when assessed in a mixture with the other EDCs, the degradation efficiency of dimethyl phthalate increased compared to its individual treatment. Furthermore, four degradation intermediates were identified for each contaminant. Finally, toxicity tests revealed that the initial solution was more toxic than the samples treated for all the contaminants tested, except for the phthalate.

Graphene oxide-wrapped tungsten trioxide for adsorptive removal of methylene blue

Graphene oxide (GO) is a graphene derivative, but different from graphene (Gr), it has a high dispersibility and a high potential to composite with other materials. In order to reveal the effect of graphene oxide (GO) on the enhancement of methylene blue (MB) adsorption, in this study, different GO contents (0, 0.3, 0.5, and 0.7 wt%) were in situ composited with tungsten oxide nanostructures prepared by a simple one-pot hydrothermal method. The physicochemical analysis implies that the in situ compositing helps create a strong interaction between GO and platform material - tungsten oxide. As the GO content increased from 0 to 0.7 wt%, the average crystallite size decreased slightly from 26.7 nm to 24.0 nm, while the microstrain increased from 0.31 to 0.53 %, respectively. Both pristine and nanocomposite samples showed good adsorption capacity with methylene blue (MB), which increases with GO content in the nanocomposites. The sample composited with 0.7 wt% GO showed the highest adsorption activity with the highest adsorption capacity of 76.1 mg/g after 150 min at the optimum condition (15 mg absorbent and 100 ml of MB 30 mg/ml). The MB adsorption kinetics is consistent with the second-order kinetics model with the maximum rate of 2.3 × 10−3 g/mg·m at the optimum condition, while the adsorption isotherm is well described by the Langmuir model with the Langmuir adsorption constant of 0.37 l/mg. These results show that the one-pot hydrothermal method is a facile and efficient method for in situ preparing the Gr-based nanocomposite absorbent.

Tungsten oxide nanostructures for all-vanadium redox flow battery: Enhancing the V(II)/(VIII) reaction and inhibiting H2 evolution

Vanadium redox flow batteries (VRFBs) offer remarkable performance capabilities for renewable energy power plants. However, the kinetics of the VRFBs' redox reactions are slow and the efficiency is low due to parasitic reactions such as the hydrogen evolution reaction (HER). In this work, to overcome these limitations, the effect of modifying the carbon cloth electrode with tungsten oxide nanowires, nanoflakes, and nanospheres prepared was elucidated for the negative half-cell reaction V(II)/V(III). The physical and chemical properties of those nanostructures were characterized using FESEM, XPS, XRD, FTIR, and contact angle measurements. The effect of the catalyst loading and structure, pH and composition of the synthesis solution, and the presence of binder on catalytic activity was evaluated using CV and EIS. The results showed that the effective loading of all three structures is ~2 mg/cm2, with all of the structures showing a significant enhancement of the V(II)/(VIII) reaction kinetics in comparison to the untreated carbon cloth and greater stability than the thermally treated carbon cloth. The tungsten oxide nanostructures prepared at pH 2 showed the best catalytic activity, with the suppression of hydrogen evolution reaction (HER) being inversely proportional to the number of defects. Tungsten oxide nanoflakes prepared at pH 2 using water as a solvent exhibited the optimum balance between promoting the V(II)/(VIII) reaction kinetics and suppressing the HER. The performance evaluation in a two-electrodes setup of all‑vanadium RFB revealed that the WNFs structure have the highest charge/discharge capacity and energy efficiency at a relatively high current density of 60 mA/cm2 due to its improved kinetics.

Tungsten Oxide-Based Materials as Catalyst Support for Oxygen Evolution Reaction

The high cost of iridium (Ir) is a major concern for the large scale deployment of polymer electrolyte membrane water electrolysis (PEMWE). To mitigate its impact, the usage of Ir on the anode must be significantly reduced. Down-sizing the catalyst particle is a straight forward strategy but requires the use of appropriate support materials to disperse and anchor fine Ir nanoparticles. We have investigated the use of tungsten oxide-based materials as support for the oxygen evolution reaction (OER) Ir and ruthenium (Ru) catalyst. The synthesis of nanostructured substoichiometric tungsten oxide and the subsequent loading of ultrafine Ir/Ru-based nanoparticles is thoroughly studied. Due to the successful loading, the mass activity of the tungsten oxide-supported Ir/Ru-based catalyst shows significant improvements under rotating disk electrode (RDE) conditions compared with commercially available Ir/Ru-blacks. Furthermore, non-destructive depth profiling by synchrotron-based X-ray photoelectron spectroscopy (XPS) has revealed the strong catalyst-support interaction which suppressed the oxidation of the supported Ir/Ru-based catalysts, leading to much enhanced durability under accelerated durability testing conditions. To verify its performance under practical PEM electrolysis conditions, the tungsten oxide-supported OER catalyst is directly coated onto a polymer electrolyte membrane, i.e., forming a catalyst coated membrane (CCM), and tested under single cell testing conditions without pressure differential. The voltage dependent chemical state of the supported catalyst is also probed in-situ by synchrotron-based XPS where a potential dependent electron transfer between the catalyst and tungsten-oxide support is discovered. Our discovery is anticipated to aid the development of cost effective PEM electrolysis anodes.

Exploring the synergistic effect of temperature on hydrothermally synthesized tungsten oxide (WO3) nanostructures and its role in asymmetric liquid-state hybrid supercapacitors

The objective of this study was to produce non-uniform nanostructures (NSs) with different crystalline structures of the tungstate oxide (WO3) using the simple hydrothermal method for the supercapacitor application to overcome the critical energy crisis. In these aspects, the prepared WO3-NSs have been thoroughly examined using various physio-chemical methods likely Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Raman spectroscopy, Scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The supercapacitive characteristics of WO3-NSs Ni-foam (NF) based electrodes were studied using an aqueous 2 M KOH electrolyte. According to the findings, the W3-NF electrode exhibits a higher specific capacitance (Cs) of 750 F/g and capacity (Csp) of 94 mAh/g with moderate specific energy (Ed), power densities (Pd) of 22 Wh/kg, and 600 W/kg at 5 mA/cm2, as well as capacitive retention of 91% after 5000 cycles. Furthermore, an asymmetric liquid state hybrid device (ASH) was fabricated using WO3-NF and GO-NF as the positive and negative materials respectively. The ASH device delivers a maximum Ed of 32 Wh/kg and Pd of 1170 W/kg while maintaining capacitive retention of 90% over the 4000 cycles of charging and discharging. Therefore, the findings have sparked significant interest in exploring the synthesis, and performance evaluation of WO3-NSs for SCs applications.

Light-powered soft actuator doped with different shaped tungsten oxide (W18O49) nanostructures: The role of shape

Light-powered soft actuator doped with different shaped tungsten oxide (W18O49) nanostructures: The role of shape

Regulating NIR reflecting property of hydrothermally synthesized tungsten oxide nanostructures via calcination

Present work primarily aims to study the near infrared (NIR) reflecting property of tungsten oxide nanostructures synthesized using hydrothermal method. As-synthesized hydrated tungsten oxide (WO3. H2O) sample was subjected to calcination at temperatures 300, 600, 700, 800 and 900 °C respectively for 1 h and corresponding NIR reflecting performance of the obtained anhydrous tungsten oxide (WO3) nanostructures was analyzed using spectrophotometer. Thermal, structural, morphological, compositional and photoluminescence properties of the nanostructures were also characterized. Moreover, color variation of all samples was identified using CIE L*a*b* color analysis. The sample calcined at 600 °C showed a remarkable NIR reflectance of 91% with color coordinates L* = 70.21, a* = − 4.28, b* = 22.47, h* = 100.78°, and C* = 22.87. Particle size and oxygen vacancies were found to play a significant role in NIR reflectance ability of tungsten oxide. The present work provides new insight into developing NIR reflecting tungsten oxide powders to be used as environmentally friendly cool materials for buildings and automobiles with energy saving performance.

A disposable sensor based on one-pot synthesized tungsten oxide nanostructure-modified screen printed electrodes for selective detection of dopamine and uric acid.

Here, screen-printed carbon electrodes (SPCEs) were modified with ultrafine and mainly mono-disperse sea urchin-like tungsten oxide (SUWO3) nanostructures synthesized by a simple one-pot hydrothermal method for non-enzymatic detection of dopamine (DA) and uric acid (UA) in synthetic urine. Sea urchin-like nanostructures were clearly observed in scanning electron microscope images and WO3 composition was confirmed with XRD, Raman,FTIR and UV-Vis spectrophotometer. Modification of SPCEs with SUWO3 nanostructures via the drop-casting method clearly reduced the Rct value of the electrodes, lowered the ∆Ep and enhanced the DA oxidation current due to high electrocatalytic activity. As a result, SUWO3/SPCEs enabled highly sensitive non-enzymatic detection of DA (LOD: 51.4nM and sensitivity: 127µAmM-1cm-2) and UA (LOD: 253nM and sensitivity: 55.9µAmM-1cm-2) at low concentration. Lastly, SUWO3/SPCEs were tested with synthetic urine, in which acceptable recoveries for both molecules (94.02-105.8%) were obtained. Given the high selectivity, the sensor has the potential to be used for highly sensitive simultaneous detection of DA and UA in real biological samples.

Cu-doped W18O49 nanowire reticular films for electrochromic supercapacitors

The method of improving the electrochromic properties of tungsten oxide by doping has attracted great interest. In this study, we successfully fabricated nanostructured tungsten oxide with different copper doping concentrations by a solvothermal method using copper chloride dihydrate and tungsten hexachloride as precursors. We found that the area-specific capacitance of the films gradually increased with the increase in doping concentration. The products were characterized by x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, cyclic voltammetry, and chronoamperometry. The results show that the films we fabricated are reticular structures composed of nanowires. The doping of copper can improve the electron conductivity and shorten the ion transmission distance, thus improving energy storage properties. When the doping concentration is 7% and the annealing temperature is 200 °C, the film had the largest surface capacitance of 17.89 mF/cm2 and the capacitance retention reached 58.23%.

Mesoporous PdO–loaded WO3 nanocrystals: A promising photocatalyst for highly efficient photoreduction of nitrobenzene to aniline under visible light

BackgroundNitrobenzene (NTB) conversion to aniline (AN) is a key technology for large-scale industrial chemical production and wastewater treatment. Accordingly, photocatalytic reduction of nitrobenzene has emerged as a green technology to produce aniline. MethodsThis study offers a simple nontoxic surfactant-assisted fabrication of mesoporous tungsten oxide (WO3) nanostructures accompanied by the incorporation of tiny contents (0.5‒2.0 wt%) of palladium oxide (PdO) nanoparticles through impregnation and calcination. Significant findingsPhysicochemical investigations of fabricated heterostructures revealed the formation of mesoporous surfaces and showed the implication of PdO loading on textural and optoelectronic characteristics of WO3. Only 2.0 wt% PdO on the WO3 surface caused a notable decline in the energy bandgap from 2.77 to 1.07 eV, confirming visible light-harvesting improvement. The prepared PdO–loaded WO3 was examined for NTB photoreduction to AN. The optimum content of 1.5 wt% PdO/WO3 (2.0 g L–1) exhibited a complete phototransformation of NTB to AN after only 40 min with excellent reusability and recyclability. The PdO loading significantly facilitated photoinduced charge carriers’ separation and mobility through the construction of Step (S)-scheme heterojunction. This work opens the door for developing semiconductor-based photocatalysis as a green process for effectively converting contaminated water into useful value-added chemicals.

Enhanced photoelectrochemical water oxidation by Fe(II) modified nanostructured WO3 photoanode

Herein, we demonstrate a facile surface treatment of a nanostructured tungsten oxide (WO3) film by Fe2+ ions as a novel post-fabrication technique for enhanced photo-electrochemical water oxidation under sunlight. The structural, optical, morphological and elemental characterizations of the n-type WO3 nanoplates based electrodes have been done using X-ray diffraction, UV–visible diffuse reflectance spectroscopy, fluorescence spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis and X-ray photoelectron spectroscopy, respectively. The modified WO3 photoanodes have been subsequently examined for photo-electrochemical response by linear sweep voltammetry, photo-amperometry, electrochemical impedance spectroscopy (Nyquist plot) and Mott-Schottky analysis under AM 1.5 G solar simulated light. The optimized WO3 film with Fe:W ratio of ∼1:25, (Fe2+:Fe3+ ratio of ∼3:2) at the surface exhibited up to 3 times higher and more stable photocurrent under back illumination than that for untreated WO3 indicating the success of the surface treatment. Investigations revealed that the improved performance is a consequence of an improved charge transfer process at the interface resulting in lowering of unwanted recombination.

In Situ Synthesis of Co-WO3 Anodic Layers for Enhanced Photoelectrochemical Water Splitting

Photoelectrochemical water splitting under solar radiation is one of the most studied areas of science. However, there are still many problems connected with this topic such as the low efficiency of systems or their usability only in the region of ultraviolet radiation. Anodic metal oxides are used as working electrodes in PEC cells due to their unique geometry, relatively high surface area, simple preparation, and their unique properties. Nanostructured tungsten oxide is characterized by strong photocorrosion stability in aqueous solutions and stable physicochemical properties. The main advantage of this material is its bang gap energy (2.6 eV), which is much lower than that of the commonly used titanium dioxide (3.2 eV). In consequence, absorption in the visible light region is significantly increased (up to 12% of the solar spectrum). The main objective of this project is to develop and optimize the single-step fabrication method of cobalt-doped nanostructured anodic tungsten oxide with enhanced photoelectrochemical properties under solar radiation. Particular attention will be paid to finding the correlation between the concentration of Co2+ ions in the electrolyte and their amount embedded in the anodic layer. A complex characterization (SEM/EDS, XRD, XPS, UV-Vis DRS) of nanostructured Co-WO3 layers will be performed to establish correlations between material morphology, composition, structure, and its optical, semiconducting, spectro-, photo- and electrochemical properties.AcknowledgementsThis research was partially funded within the budget of the "Excellence Initiative - Research University" program at the Jagiellonian University in Krakow.

Deposition of Nanostructured Tungsten Oxide Layers by a New Method: Periodic Modulation of the Deposition Angle.

Periodic modulation of the deposition angle (PMDA) is a new method to deposit nanostructured and continuous layers with controllable periodic density fluctuation. The method is used for the magnetron sputtering of a WO3 layer for an electrochromic device (ECD). An experimental study indicates that the electrochromic coloration-bleaching rate nearly doubles and the electrochromic efficiency grows by about 25% in comparison with the traditional method. The ECD efficiency rises with the increasing degree of nanostructure ordering, surface roughness, and homogeneity of the WO3 layer. The method is promising for coating deposition techniques needed to produce versatile devices with specific requirements for ion transport in surface layers, coatings, and interfaces, such as fuel cells, batteries, and supercapacitors.

Acid substitutions for WO3 nanostructures synthesis by the hydrothermal route and its effect on physio-chemical and electrochemical properties for supercapacitors

In this study, we have developed a feasible and eco-friendly electrode material for supercapacitor (SCs) application by effectively synthesizing different morphological structures of tungsten oxide nanostructures (WO3-NSs). The concentrated acids play a crucial role in the synthesis of WO3-NSs and are employed to evaluate the electrochemical activity. The stable phase formation and the crystal structures of WO3-NSs were confirmed by thermogravimetric and X-ray analysis. From the field emission scanning electron microscope (FE-SEM), the hexagonal-shaped nanosheets, one-dimensional nanorods (1D NRs), and heterogeneous non-uniform agglomerated nanosheets were observed for the WO3-NSs. The presence of functional groups and the stretching-bending vibrations of WO bonds were detected by Fourier transform infrared, and Raman spectroscopy respectively. The transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) offers a more in-depth morphological, structural, and elemental composition and electronic states investigation of the optimized WO3-NRs. Additionally, the electrochemical properties of the WO3-NSs have been examined in 1 M KOH electrolyte using Nickel Foam (NF) as a current collector. Furthermore, the M-WO3-NF electrode reveals higher specific capacity (Csp) and gravimetric capacitance (Cg) of 72 mAh/g and 600 F/g with high energy density (Ed) of 17 Wh/kg, and power density (Pd) of 321 W/kg as well as the superior Columbic efficiency (96.9 %) at 5 mA/cm2. The M-WO3 electrode exhibits 91 % capacitive retention over 5000 cycles. The M-WO3-NF is used as the cathode and activated carbon (AC) as the anode in the design of an aqueous hybrid supercapacitor (AHSC) device. Notably, the M-WO3-NF//AC-NF device offers a Pd of 1060 W/kg at an Ed of 9 Wh/kg and remarkable electrochemical stability of 80 % over 3000 charge-discharge cycles. These results highlight the excellent electrochemical functionality and advantages of the M-WO3-NRs as a promising cathode for practical energy-storage systems.

Tungsten oxide nanostructures peculiarity and photocatalytic activity for the efficient elimination of the organic pollutant.

The WO3 nanostructures were synthesized by a simple hydrothermal route in the presence of C14TAB and gemini-based twin-tail surfactant. The impact of using these special shape and size directing agents for the synthesis of nanostructures was observed in the form of different shapes and sizes. The WO3 web of chains type nanostructure was obtained using C14TAB in comparison to the cube-shaped nanoparticles through twin-tail surfactant. On contrary, the twin-tail surfactant provides sustainable and controlled growth of cube shape nanoparticles of size ~ 15nm nearly half of the size ~ 35nm obtained using conventional surfactant C14TAB, respectively. For the detailed structural features, the Williamson-Hall analysis method was implemented to find out the crystalline size and lattice strain of the prepared nanostructures. Owing to the strong quantum confinement effect, the WO3 cube-shaped nanoparticles with an optical band gap of 2.69eV of the prepared nanoparticles showed excellent photocatalytic efficacy toward organic pollutant (fast green FCF) compared to the web of chain nanostructures with an optical band gap of 2.66eV. The ability of the prepared systems to decompose the organic pollutant (fast green FCF) in water was tested under visible light irradiations. The percentage degradation was found to be 94% and 86% for WO3 cube-shaped nanoparticles and WO3 web of chains, respectively. The simplicity of the fabrication method and the high photocatalytic performance of the systems can be promising in environmental applications to treat water pollution.

Plasma-based one-step synthesis of tungsten oxide nanoparticles in short time

Nanostructured tungsten oxide as a semiconductor metal oxide has attracted considerable attention due to its promising and notable properties. Tungsten oxide nanoparticles can be used in a wide range of technology and applications such as catalysts, sensors, supercapacitors, etc. In this study, nanoparticles were prepared via a simple method using an atmospheric glow discharge. This modern approach had many advantages such as high efficiency and straightforward function. Synthesis performance was done in only one step and a short time which started at 2 min and had been continued for 8 min. The X-ray diffraction pattern revealed the formation {mathrm{WO}}_{3} at atmospheric pressure. The synthesized particle size was characterized using scanning electron microscopy. According to the experimental results, the synthesis was greatly influenced by the applied voltage, gas type, and plasma forming side over the water surface. Increases in electrical potential difference and thermal conductivity of the gas led to a greater rate of synthesis, while this rate was reduced by decreasing the atomic weight of the gas.