WO3 Nanostructures Research Articles

Development of a 1D-WO3 and CuO nanocomposite modified electrode for enhanced detection of 2,4-dichlorophenol

A common chlorinated phenol known as 2,4-dichlorophenol (2,4-DCP) was investigated electrochemically using cyclic voltammetry (CV) and square wave voltammetry (SWV). The electrochemical investigation was carried out at 1D nanostructured tungsten dioxide (WO3) and copper (II) oxide (CuO) nanocomposite-modified carbon paste electrode (CPE). The electrode's sensitivity was improved by the WO3/CuO nanocomposite, enabling investigators to more precisely measure the 2,4-DCP's electrochemical characteristics. The hydrothermal method was utilized to synthesize the WO3 NPs. The XRD, AFM, SEM, and EDS techniques were used to characterize the nanocomposite and WO3 NPs. Numerous parameters have been studied, including pH, concentration variation, scan rate variation, and accumulation time. Samples of soil, fruits, and vegetables were examined using the fabricated WO3/CuO/CPE. In the concentration range of 7.0 × 10−8 M to 2.6 × 10−7 M, a linear relationship was established along with the lower limit of detection of 0.17 × 10−8 M and the limit of quantification of 0.57 × 10−7 M. The 0.2 M phosphate buffer (PB) of pH 10.4 increased the peak current, which contributed to the WO3/CuO/CPE sensor's sensing performance and was highly sensitive with respect to 2,4-DCP detection. Anodic peak current was observed for the WO3/CuO/CPE is at -7.45 µA whereas for unmodified CPE is at -1.31 µA. According to the findings, the nanostructured WO3 and CuO nanocomposite showed exceptional sensitivity in identifying the electrochemical characteristics and reactions of 2,4-DCP.

Growth of WO3 nanostructure deposited on TiO2 nanotube arrays for electrochemical enzyme-free glucose sensor

In this study, a novel WO3-TiO2 hybrid nanostructure-based electrochemical non-enzymatic glucose biosensor has been developed. The anodization method was utilized to successfully produce TiO2 nanotubes on Ti6Al4V alloy functioning as substrates and WO3 nanomaterial decorate on the surface of TiO2 nanotubes (TNTs) deposited through electrochemical technique. The incorporation of WO3 on TNTs has resulted in a high electroactive surface and more degradation resistance in comparison to pure TNTs, resulting in enhanced electron transfer rate and electrode stability. High-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction were used to investigate the crystalline structure and morphology of the WO3-TiO2 nanostructure. The electrochemical properties of the hybrid electrodes were investigated employing amperometry, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The hybrid electrode had a promising sensitivity (1228.12 μA/mM/cm2), low detection limit (0.19 mM), wide linear range (1.0–6.5 mM), and short response time (2-s). The sensors also demonstrated superior levels of reproducibility, repeatability, and stability.

Facile preparation of a highly efficient coin cell supercapacitor based on WO3 nanorods

Developing sustainable energy storage devices is challenging for the progress of energy storage applications. Here, nanotechnology represents a strategic route to reduce the amount of used critical materials, while continuing to take advantage of their properties, thanks to the high surface to volume ratio which characterizes nanostructures. WO3 nanostructures represent a promising active material for energy storage applications, thanks to their wide capability of small positive ions (H+ and Li+) intercalation and their high stability in acidic conditions. The coupling between WO3 nanorods and carbon black powder is studied to realize a highly efficient coin cell supercapacitor. The morphology of WO3 nanorods and carbon black is investigated by using a scanning electron microscope, and the energy storage performances were evaluated by performing cycling voltammetry and galvanostatic charge and discharge analysis, thus obtaining promising specific capacitance results (79 and 70 F/g at 5 mV/s and 0.5 A/g respectively). Moreover, the stability of the obtained coin cell was investigated, thus getting good capacity retention over 250 charge-discharge cycles. Energy and power densities were also calculated, obtaining the highest energy density of 39 Wh/kg at a power density of 500 W/kg. The WO3‑carbon black coin cells are used to power a red LED, so demonstrating the viability for practical applications.

Synthesis of light green sheets like WO3 nanostructures for room temperature humidity sensing applications

Synthesis of light green sheets like WO3 nanostructures for room temperature humidity sensing applications

Raman Study of Novel Nanostructured WO3 Thin Films Grown by Spray Deposition.

The present communication reports on the effect of the sprayed solution volume variation (as a thickness variation element) on the detailed Raman spectroscopy for WO3 thin films with different thicknesses grown from precursor solutions with two different concentrations. Walls-like structured monoclinic WO3 thin films were obtained by the spray deposition method for further integration in gas sensors. A detailed analysis of the two series of samples shows that the increase in thickness strongly affects the films' morphology, while their crystalline structure is only slightly affected. The Raman analysis contributes to refining the structural feature clarifications. It was observed that, for 0.05 M precursor concentration series, thinner films (lower volume) show less intense peaks, indicating more defects and lower crystallinity, while thicker films (higher volume) exhibit sharper and more intense peaks, suggesting improved crystallinity and structural order. For higher precursor concentration 0.1 M series, films at higher precursor concentrations show overall more intense and sharper peaks across all thicknesses, indicating higher crystallinity and fewer defects. Differences in peak intensity and presence reflect variations in film morphology and structural properties due to increased precursor concentration. Further studies are ongoing.

Synergistic effect of Ni doping on the dielectric and electrochemical properties of WO3 nanostructures for supercapacitor applications

Synergistic effect of Ni doping on the dielectric and electrochemical properties of WO3 nanostructures for supercapacitor applications

Investigation of radiation effects on structural, morphological, and compositional properties of WO3 nanostructures for water splitting applications

Investigation of radiation effects on structural, morphological, and compositional properties of WO3 nanostructures for water splitting applications

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.

Photoelectrochemical disinfection efficiency of WO3-based photoanodes: Development of multifunctional photoelectrocatalytic materials

Access to safe water is a growing global concern, with millions lacking acceptable water sources. Photocatalysis offers eco-friendly water remediation, yet its combination with electrocatalysis for both water treatment and hydrogen production remain underexplored. This study investigates UVA LED photoelectrocatalysis using WO3-based photoanodes, alone or in heterojunction with BiVO4, to purify wastewater and co-produce hydrogen. Tests on polluted water streams containing 105 PFU mL−1 of MS2 bacteriophage virus and 106 CFU mL−1 of E. coli reveal that nanostructured WO3 achieves rapid MS2 disinfection within 5 min. (k= 0.80 min−1), with enhanced efficiency over flat counterparts. However, nanostructuring does not improve E. coli inactivation due to bacterium size constraints. These findings advance the design of tandem photoreactors for dual wastewater purification and energy generation.

Novel existence of Mn and Cu in WO3 nanostructures for promising photocatalytic activity against MB dye and Levofloxacin antibiotic

To enhance photocatalytic degradation of MB dye and Levofloxacin antibiotic, facile coprecipitation strategy was used to synthesize pure WO3 and novel Mn-Cu codoped WO3 nanostructures. The synthesized nanostructures were probed by XRD, SEM, EDX, FTIR, XPS, BET, TEM, PL and UV–vis spectra to analyze optical and morphological properties. Pure WO3, Mn2%-Cu1%-WO3, Mn2%-Cu3%-WO3, Mn2%-Cu5%-WO3 and Mn2%-Cu7%-WO3 were optimized novel materials that were used for water treatment against model impurities. Optical properties of pure WO3 were enhanced to successfully increase the photocatalytic degradation of principal water pollutants. Over a time span of 175 minutes, 86.7% of MB dye was degraded and 75.9% Levofloxacin was degraded by an average of 49 nm and 2.16 eV bandgap Mn2%-Cu5%-WO3 optimal sample. Due to smaller particle size, surface to volume ratio gave more active sites to the photocatalysts for pollutants degradations. Interestingly, just 15% degradation loss was observed after consecutive 6 cycles against the degradation of MB dye and 9.1% loss against Levofloxacin medicine after 6 photocatalytic runs. XPS spectra offered crucial insights into the elemental composition and chemical states of the Mn-Cu-WO3 nanostructures. According to these findings, Mn-Cu-WO3 can be used as a good candidate with long time stability against pollutants degradations.

Eco-friendly Synthesis of WO3 Nanostructures for Near-Infrared Laser Improved Photothermal Therapy of Breast Cancer

Eco-friendly Synthesis of WO3 Nanostructures for Near-Infrared Laser Improved Photothermal Therapy of Breast Cancer

Synthesis and Characterization of WO3 Nanostructures by the Solvothermal Method for Electrochromic Applications

Synthesis and Characterization of WO3 Nanostructures by the Solvothermal Method for Electrochromic Applications

Simultaneous degradation of methyl orange and indigo carmine dyes from an aqueous solution using nanostructured WO3 and CuO supported on Zeolite 4A

In this study, a novel composite catalyst system, Zeolite 4A/WO3/CuO with a Z-scheme design, was synthesized for photocatalysis, sonocatalysis, and sono-photocatalysis methyl orange (MO) and indigo carmine (IC) dyes simultaneously. The properties of the Zeolite 4A/WO3/CuO composite were thoroughly investigated using various techniques, and the results confirmed the synthesis of the desired catalyst system. In the sono-photocatalytic process, using the Zeolite 4A/WO3/CuO composite, the maximum efficiency for MO (99.12 %) and IC (97.24 %) was achieved at pH of 2 and 3, with a catalyst dosage of 0.15 g/L, a dye concentration of 10 mg/L, a contact time of 25 min, and H2O2 dosage of 30 µL/100 mL. The dye elimination efficiency using the sono-photocatalytic process was reduced in the presence of Cl- and PO43- in the distilled water. The efficiency also declined in the medium of river and well water resources. Moreover, the Zeolite 4A/WO3/CuO catalyst maintained over 90 % of its performance even after five reuse cycles. Based on the kinetic study, the sono-photocatalytic process exhibited higher activation for the removal of MO (k: 0.1946 min−1 and t1/2: 3.561) and IC (k: 0.1433 min−1 and t1/2: 4.836) than other processes. The synergy values for the MO and IC degradation using the Zeolite 4A/WO3/CuO composite were determined to be 2.167 and 2.303, respectively. The impact of various scavengers demonstrated that in the degradation processes of the target dyes using the sono-photocatalytic process, different active species like OH•, e-, h+, and O2–• are involved. The purification of dye-laden water using the sono-photocatalytic process was not toxic for plant germination, microorganisms, and fish, highlighting the successful biocompatibility of the process for dye removal.

WO3 nanostructures produced from tungsten welding electrode scraps: Temperature influence on optical and morphological characteristics

Methods to produce WO3 nanostructures have become important due to the possibility of using this material in a wide range of technological applications. In this context, a hydrated WO3.2H2O structure was produced by the electrochemical dissolution of welding electrode scraps in an alkali aqueous solution, followed by acid precipitation. The thermal treatment of this precursor structure at 550, 700, 850, and 1000 °C was able to produce γ phase WO3 materials with a monoclinic crystalline structure at all the temperatures used, as demonstrated by XRD and RAMAN characterization. However, different treatment temperatures can yield materials with diverse morphologies and optoelectronic properties. For example, the material produced at 1000 °C presented an elongated nanorod shape, with dimensions, from the base, ranging between 50 and 500 nm, a length of about 4 μm, and the lowest Eg value. The spectroscopic characterization also demonstrated that above 700 °C, the thermal treatment could eliminate the crystallization water and create oxygen vacancies, mainly at 850 and 1000 °C; explaining the decrease in the Eg values with increased temperature. As proof of concept, photocatalytic degradation of the Reactive Black 5 dye demonstrated that the material produced at 1000 °C was able to discolor ca. 50% of the initial color. Broad DFT analyses were performed, carefully describing the surface properties and the influence of morphology on the material properties. Therefore, we demonstrated that a simple, fast and low-cost two-step process was successfully developed aiming at a noble reuse of residues of this important material.

Anodizing Tungsten Foil with Ionic Liquids for Enhanced Photoelectrochemical Applications.

This research examines the influence of adding a commercial ionic liquid to the electrolyte during the electrochemical anodization of tungsten for the fabrication of WO3 nanostructures for photoelectrochemical applications. An aqueous electrolyte composed of 1.5 M methanesulfonic acid and 5% v/v [BMIM][BF4] or [EMIM][BF4] was used. A nanostructure synthesized in an ionic-liquid-free electrolyte was taken as a reference. Morphological and structural studies of the nanostructures were performed via field emission scanning electron microscopy and X-ray diffraction analyses. Electrochemical characterization was carried out using electrochemical impedance spectroscopy and a Mott-Schottky analysis. From the results, it is highlighted that, by adding either of the two ionic liquids to the electrolyte, well-defined WO3 nanoplates with improved morphological, structural, and electrochemical properties are obtained compared to samples synthesized without ionic liquid. In order to evaluate their photoelectrocatalytic performance, the samples were used as photocatalysts to generate hydrogen by splitting water molecules and in the photoelectrochemical degradation of methyl red dye. In both applications, the nanostructures synthesized with the addition of either of the ionic liquids showed a better performance. These findings confirm the suitability of ionic liquids, such as [BMIM][BF4] and [EMIM][BF4], for the synthesis of highly efficient photoelectrocatalysts via electrochemical anodization.

Hydrothermally synthetized WO3 coated stainless steel mesh for oil–water separation purposes

To separate oil–water mixtures especially in oil field operations, new energy-efficient methods are urgently required. Conventional separation techniques using demulsifiers for separation of oil–water mixtures or even use of membranes usually suffered from high cost and energy consumption, composition dependency of demulsifiers and fouling or inability of a single membrane to separate all types of oil–water mixtures. This research aimed to synthesize tungsten oxide-coated stainless steel mesh using the hydrothermal method, with a focus on evaluating its effectiveness in oil–water separation. The coating procedure was carried out using hydrothermal techniques, with an emphasis on investigating the impact of precursor concentration, pH levels, reaction temperature and duration, on the separation efficiency of the optimal coating solution. The hydrothermally coated stainless steel mesh was created within a polytetrafluoroethylene reaction vessel, submerged in a 150 ml aqueous solution containing 0.0094 mol of sodium tungstate di-hydrate at pH 3.0, achieved through the addition of hydrochloric acid. Additionally, 1 g of oxalic acid, acting as a chelating agent, was introduced. Subsequently, the mesh underwent a 4 h reaction at 220 °C and was subsequently annealed for 30 min in a 350 °C furnace. Remarkably, the resultant mesh exhibited an exceptional water separation flux of 9870 ± 15 L/hr/m2 when exposed to 1:1 v/v oil–water mixtures. This performance significantly outperformed previous filters designed for similar oil–water separation tasks. The mesh efficiently facilitated the passage of water through the oil–water mixture, achieving an efficiency rate exceeding 98 ± 1%. To gauge its wetting behavior, the hydrophilic/underwater oleophobic filter underwent static contact angle measurements. The filter's wetting mechanism was primarily attributed to its hierarchical surface structure, which enhanced surface hydrophilicity and roughness. Analytical techniques such as XRD, FTIR, and FE-SEM were employed to scrutinize the fabricated filter's composition. These analyses confirmed the successful creation of a nanostructured WO3 coating on both sides of the stainless steel mesh. Moreover, the utilization of commercially available chemicals and straightforward fabrication techniques underscores the promising potential of this approach for large-scale applications.

Enhancement of the catalytic performance of Co-ZIF/WO3 heterostructures for selective catalytic reduction of NOx

AbstractNitrogen oxides (NOx) are one of the growing air pollutants in industrial countries, and their emissions are regulated by stringent legislation. Therefore, the design of the catalyst comprised of metal oxides and ZIFs a potential solution for improving selective catalytic reduction (SCR) of NOx. Here, an efficient strategy was described to fabricate Co-ZIF/WO3 heterostructures for SCR of NOx. First, WO3 nanostructures were fabricated by the solvothermal method, and subsequently epitaxial growth of ZIF-67 on the metal oxide surface to create a new type of semiconductor Co-ZIF/WO3 heterostructures. The obtained heterostructures were systemically characterized by wide-angle XRD, FESEM, UV DRS, FT-IR, AFM, and TEM spectroscopies. The Co-ZIF/WO3 heterostructures shift the temperature corresponding to the maximum conversion around 50 °C towards lower temperatures. The maximum conversion is substantially enhanced from 55% at 400 °C to 78% at 350 °C. The enhanced activity is attributed to better interaction and synergic effect of WO3 incorporated into ZIF-67 and also the electron transfer facility between the WO3 and Co species in Co-ZIF/WO3 heterostructures. Moreover, Co-ZIF/WO3 results in a distinct effect on the production of carbon monoxide (CO) in the product gas stream. The current study highlights some of the challenges in the development of semiconductor-based heterostructures for a decrease in air pollution.

Molybdenum induced defective WO3 multifunctional nanostructure as an electrochromic energy storage device: Novel assembled photovoltaic-electrochromic Mo–WO3 film

In this work, a self-powered electrochromic device incorporating molybdenum-doped tungsten oxide (WO3) is developed for enhanced performances, offering a potential solution for energy efficient technologies. Defective nanostructure of WO3, enabled with molybdenum doping, is achieved through an electrochemical co-deposition method. A film of Mo–WO3 is investigated for multifunctional purposes, acting as both an electrochromic (EC) and energy storage device (ESD). As an EC film, it exhibits an optimal optical contrast of 84.5 %, minimum coloration time of 0.4 s, high coloration efficiency of 90.4 cm2/C, and excellent optical stability. In ESD applications, Mo–WO3 displays charge-transfer resistance of 7.6 Ω, a commendable capacitance of 39.1 mF/cm2, and excellent capacitance retention of 80.4 %. The integration of Mo ions into the WO3 nanostructure results in the formation of oxygen defect sites, which enhances the mobility of Li+ ions over the amorphous and deagglomerated morphology of Mo–WO3. Furthermore, the EC activity of Mo–WO3 film does not require an external power source as the film is powered by an integrated quantum dot-sensitized solar cell (QDSSCs). The open circuit voltage of 0.62 V, resulting from the QDSSCs power source, successfully facilitates the switching operation of the Mo–WO3 EC film.

Optical sensing and computing memory devices using nanostructured WO3

This paper presents microfabrication, characterization, optical sensing and memory testing using nanostructured tungsten trioxide (WO3). Different experiments were performed to realize the integrated sensing and computing memory (ISCM) functionality on the same device. These ISCM devices were fabricated using standard wafer-scale microfabrication processes on 2-inch silicon (Si) substrate. First, the devices were tested to detect the broad wavelength spectrum ranging ultraviolet (UV) to near infrared (NIR). These photosensing devices were shown repeatable, reproducible and reliable results with fast switching speed (rise time (0.05 s)/fall time (0.08 s)) at 880 nm. Further, the memory functionality was realized using the electrical and optical stimuli at room temperature. The optically stimulated device has shown higher sensitivity for 880 nm and mimics the human brain's functional characteristics. The developed ISCM devices have shown enhanced performance parameters like paired pulse facilitation (PPF) index 171.2 %, retention time 300 s, resistance switching ratio 1.5 × 102 over electrical stimulation. The tested devices are able to demonstrate ISCM features and the developed process pathway for mass production.

Nanostructured porous WO3 for photoelectrochemical splitting of seawater

Seawater, due to its salinity, can serve as an electrolyte in photoelectrochemical (PEC) systems, which have the potential to enable solar-driven production of hydrogen and oxidizing species. In this study several micrometer thick and highly porous nanostructured WO3 films were formed and their performance in photoanodic oxidation of chloride and sulfate ions, the most abundant anionic species in seawater, was investigated. Layers were characterized using scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, and BET surface area measurements. The study demonstrates that efficient PEC performance is achieved through optimal light absorption by sufficiently thick WO3 layers (3–5 μm), a highly porous structure that facilitates electrolyte permeation and ionic transport and provides a large electrochemically active interfacial area, and a nanosheet morphology where the sheet thickness is shorter than the hole diffusion length in WO3. The Faradaic efficiency of ClO- + ClO2- generation in neutral chloride-based electrolytes was found to be close to 100 %, but decreased significantly with photoelectrolysis time, presumably, due to the formation of higher chlorine oxo compounds. In addition, photocurrent stability and dissolution of WO3 photoanodes in acidic sulfate and neutral chloride media was compared. Though dissolution of WO3 in 0.5 M NaCl was found to be up to 3 times higher, photocurrent decay was more significant in 0.5 M H2SO4. The phenomenon was attributed to effective hole scavenging by surface-adsorbed Cl- ions, which prevents passivation of the photoelectrode surface due to formation of W(VI) peroxospecies.