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The present work regards a unique yet study of 3D structured surface evolution of nano-balls and walls-like features with thickness variation, for tungsten oxide (WO3) thin films made by spray deposition. Since in most optoelectronic applications the surface morphology and structure play a crucial role and WO3 is one of the most studied and used metal oxide semiconductors in a significant variety of optoelectronic applications, a detailed study of recently observed and reported unique 3D complex architecture of WO3 coatings fabricated by spray pyrolysis (starting from different precursors) is of great importance for further development of thin film coatings and devices. In this scope, two different series of WO3 of 11 samples with different thicknesses each, starting from two tungsten peroxide precursor concentrations (0.05 M and 0.1 M) were fabricated by spray pyrolysis and thoroughly characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction and Raman spectroscopy. Results suggest that, for the mentioned concentrations, the main structural differences affect mostly the surface morphology and slightly the surface texturing. These observations prove the reliability of fabrication of coatings with such surface morphology by spray pyrolysis method and open new perspectives for better sensors, electrochromic or photochromic devices, and more. [ABSTRACT FROM AUTHOR]

In this research, tungsten oxide nanocrystals with polymerized spherical, rod, and sheet structures were synthesized using a solvothermal method with WCl₆ as the tungsten source in three different solvent environments: ethanol, an ethanol/water mixture, and pure water. The size and morphology of the tungsten oxide nanocrystals were tuned in a cost-effective manner. Polymerized spherical tungsten oxide synthesized in ethanol consisted of nanorods with diameters of 6–10 nm; rod-shaped tungsten oxide with diameters of 150–260 nm was obtained in the ethanol/water mixture; and sheet-like tungsten oxide synthesized in pure water had dimensions of 50–100 nm × 40–200 nm. Gas sensitivity tests revealed that the synthesized materials were highly selective for acetone, with the polymerized spherical tungsten oxide showing a sensitivity as high as 25.4 at 100 ppm acetone concentration. This difference in gas-sensing properties is attributed to variations in the microstructure and crystal properties of tungsten oxide nanocrystals formed under different solvent conditions. This research provides a new perspective for the design and optimization of gas sensor materials, demonstrating that modulating the solvent type can optimize gas-sensitive performance, which is of significant research importance. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) electrocatalyst was improved the problem of insufficient activity and slow reaction kinetics by sulfur doping. Sulfur-doped tungsten oxide (S-WO3) electrocatalysts with different doping concentrations were successfully synthesized by the secondary calcination method. The effects of doping concentration on its morphology, structure and electrochemical properties have been systematically studied. The results show that sulfur doping into tungsten oxide can modulate the electronic structure while introducing oxygen defects. It significantly improves the electrocatalytic activity of tungsten oxide. The S-WO3-1 catalyst using a sulfur powder amount of 0. 11 g had the best sulfur doping concentration. The catalyst requires only 161 mV overpotential to achieve a current density of 10 mA cm-2 and can sustain hydrogen evolution for up to 30 000 s which shows excellent catalytic activity and cyclic stability. This study provides a new way to develop efficient hydrogen evolution electrocatalysts. [ABSTRACT FROM AUTHOR]

The effect of treating SBA-15 with a piranha solution at room temperature was studied for purposes of stabilizing a WO3 film deposited by Atomic Layer Deposition (ALD). For unmodified SBA-15, the film was found to migrate out of the SBA-15 pore structure between 573 and 773 K; however, WO3 remained within the pores in piranha-treated samples at 773 K, as demonstrated by X-Ray Diffraction and Transmission Electron Microscopy. Although N2 adsorption isotherms showed that the pore structure of SBA-15 was unaffected by the piranha treatment, the silanol content increased, as shown by water adsorption isotherms and Diffuse Reflectance Infrared Spectra of the silanol region. Temperature-programmed desorption results for 2-propanol also suggested that the silanols were more reactive in the piranha-treated samples. The results demonstrate the importance of surface modification of SBA-15 for the preparation of supported-oxide catalysts. [ABSTRACT FROM AUTHOR]

WO3 with nanocrystal-in-glass (nanocrystal-embedded amorphous matrix) characteristics is recognized as a highly promising electrochromic material. The demand for flexible and large-area electrochromic technologies is pushing the advancement of low-temperature and large-scale processes for WO3 thin films. This study presents a functional ink designed for the low-temperature preparation of WO3 thin films using blade-coating technology, enabling scalable and cost-effective production. The optimized WO3:Ti-PEDOT hybrid electrochromic thin film demonstrates a high light modulation rate of 86.05% (@ 633 nm), a coloration efficiency of 54.1 cm2 C–1, an outstanding cycle stability exceeding 1000 cycles, and an ionic diffusion coefficient of 3.69 × 10–8 cm2 s–1. One reason for the remarkably improved electrochromic performance is the synergistic effect of the nanostructured WO3 glass-nanocrystal composites induced by Ti doping and the enhanced electrochemical reaction kinetics facilitated by the use of poly-(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer, as a binder. This work demonstrates a feasible and cost-effective method for producing WO3-based films for electrochromic smart windows, serving as an alternative to the existing vacuum-based WO3 thin film production methods. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) based metal oxide semiconductor material has been conventionally used for sensing inorganic gases at elevated temperatures. However, in this study, the gas sensing performance of tungsten oxide‐based sensors is evaluated at room temperature. In this study, WO3 quantum dots (QDs) are synthesized via the electrochemical method, followed by a microwave treatment to dehydrate them. The newly developed process is relatively less expensive and offers the flexibility to alter the structure in terms of phase, size, shape, and vacancy concentration. It is observed that electrochemical process parameters play an important role in phase evolution and control the oxygen vacancy concentration in the powder, which are essential for enhancing its gas sensing characteristics. Results showed an enhanced gas‐sensing ability of WO3 QDs at room temperature toward inorganic gases, such as CO, NO2, NH3, and H2 when subjected to microwave treatment. The enhanced gas‐sensing performance of microwave‐treated WO3 QDs is attributed to its smaller size and high oxygen vacancy concentration. The minimum limit of detection values for CO, NO2, NH3, and H2 at room temperature using microwave‐treated hydrated tungsten oxide QDs were 4.60, 1.5, 0.35, and 10.25 ppm, respectively. [ABSTRACT FROM AUTHOR]

Catalyzing hydrogen evolution reaction (HER) is a key process in high-efficiency proton exchange membrane water electrolysis (PEMWE) devices. To replace the use of Pt-based HER catalyst, tungsten carbide (W2C) is one of the most promising non-noble-metal-based catalysts with low cost, replicable catalytic performance, and durability. However, the preparation access to scalable production of W2C catalysts is inevitable. Herein, we introduced a facile protocol to achieve the tungsten carbide species by plasma treatment under a CH4 atmosphere from the WO3 precursor. Moreover, the heterogeneous structure of the tungsten carbide/tungsten oxide nanosheets further enhances the catalytic activity for HER with the enlarged specific surface area and the synergism on the interfaces. The prepared tungsten carbide/tungsten oxide heterostructure nanosheets (WO3-x-850-P) exhibit exceptional HER catalytic activity and stable longevity in acid electrolytes. This work provides a facile and effective method to construct high-performance and non-precious-metal-based electrocatalysts for industrial-scale water electrolysis. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) has gained importance in the gas sensing field, particularly for NO2 gas monitoring. The NO2 is a toxic gas that has a severe impact on the human health and the environment. In the present study, WO3 nanosheets were synthesized hydrothermally at a relatively low temperature, i.e. 100°C and characterized via FTIR, XRD, FESEM, BET and UV–VIS spectroscopy techniques. The WO3 nanosheet-based gas sensor was fabricated for NO2 gas monitoring. The NO2 sensing analysis showed that the WO3 nanosheet-based gas sensor exhibited a maximum response value of 38% for 50 ppm NO2 at 150°C operating temperature with response and recovery time of 85 s and 315 s, respectively. The detection limit of the sensor was observed up to 1 ppm of NO2. These findings highlight the potential of WO3 nanosheets for monitoring NO2 gas for the development of efficient gas sensors for sustainable environmental protection. [ABSTRACT FROM AUTHOR]

Currently, semiconductor gas sensors are of interest for various applications, including industry, medicine and environmental monitoring. One of the most important tasks in the sensor technology is to reduce the operating temperature of devices. In this paper, it is proposed to use WOx/WS2 nanostructures obtained by a hydrothermal method to solve this problem. The morphology, structure, and composition of the developed nanostructures were studied using scanning electron microscopy, reflected electron diffraction and X-ray photoelectron spectroscopy. It is shown that the nanostructures are formed by 1D and 2D nanoobjects with an average length of 200 nm and are nanocomposites consisting of tungsten oxide WOx and tungsten disulfide WS2. The study of sensory properties when exposed to isopropanol, ethanol and acetone vapors at room temperature was carried out. A reversible change in resistance is demonstrated when these gases appear in the atmosphere. Additionally, exposure to ultraviolet radiation during the measurement process leads to an increase in the response value and speed of the sensor layers in the case of interaction with isopropanol and ethanol vapors.

Platinum (Pt)‐based compounds are the benchmarked catalysts for hydrogen evolution reaction (HER) but exhibit slow kinetics in alkaline environments. The *OH accumulation on Pt surface can block active sites, affecting proton reduction and water re‐adsorption. Alloying Ruthenium (Ru) with Pt sites can significantly modulate the adsorption and desorption of water dissociation intermediates. Choosing suitable supports and utilizing metal‐support interaction (MSI) is crucial for active site optimization. PtRu alloy anchored on tungsten oxide (WO3) with rich oxygen vacancies (OV) is prepared through an ultrafast microwave‐assisted approach. Benefiting from the coupling effects between alloying and MSI, PtRu/WO3‐OV exhibits exceptionally high HER activity. In 1 m KOH, 1 m KOH + seawater, and 0.5 m H2SO4, it requires ultralow overpotentials of 9, 26, and 6 mV to achieve 10 mA cm−2, respectively. The designed catalyst surpasses commercial Pt/C in mass activity and demonstrates considerable potential for intermittent energy integration. Density functional theory reveals that alloying Ru with Pt sites significantly reduces the energy barrier of dissociating *OH, modulating blockage on the surface and then promoting the overall alkaline HER process. This study offers insights into the rapid synthesis of non‐carbon supported catalysts with Pt site modulation for alkaline hydrogen generation. [ABSTRACT FROM AUTHOR]

The crystal phase of pseudocapacitive materials significantly influences charge storage kinetics and capacitance; yet, the underlying mechanisms remain poorly understood. This study focuses on tungsten oxide (WO3), a material exhibiting multiple crystal phases with potential for energy storage. Despite extensive research on WO3, the impact of different crystal structures on charge storage properties remains largely unexplored. Here, the successful synthesis and electrochemical characterization of tetragonal WO3 are reported. This investigation demonstrates that tetragonal WO3 exhibits superior energy storage capabilities compared to other WO3 polymorphs. According to in situ Raman spectroscopy and ultraviolet photoelectron spectroscopy combined with in‐depth electrochemical analyses, this enhancement is attributed to a unique charge storage mechanism and an expanded potential window facilitated by an engineered electrode work function. This study highlights the critical role of the crystal phase in optimizing the performance of pseudocapacitive materials and provides valuable insights for the development of next‐generation energy storage devices. [ABSTRACT FROM AUTHOR]

An effective method capable of simultaneously providing antibacterial activity, blood glucose regulation, and angiogenesis promotion for healing bacteria‐infected diabetic wounds is not reported to date, but urgently required. In this study, a hydrogel composite (γ‐PGA/PDA/GOx/WOx (PPGW)), endowed with these desired attributes is fabricated by incorporating polydopamine (PDA), glucose oxidase (GOx), and tungsten oxide (WOx) nanowires into the poly(γ‐glutamic acid) (γ‐PGA) framework. The exceptional photothermal conversion properties of PDA facilitated notable antibacterial effects on bacteria‐infected diabetic wounds; GOx regulated high blood glucose by consuming glucose and generating hydrogen peroxide (H2O2); while WOx nanowires displayed remarkable photocatalytic abilities, converting H2O2 into oxygen (O2) when exposed to 808‐nm near‐infrared radiation. Density functional theory calculations and experiments are conducted to confirm the mechanism of WOx‐mediated photocatalytic degradation of H2O2 to produce O2. These transformations aided in alleviating the hypoxic conditions in wounds associated with diabetes, expediting angiogenesis, and fostering cell crawling and proliferation. Consequently, the multifunctional hydrogel dressing PPGW, featuring photothermal, antibacterial, and enzyme‐catalyzed activity reduces hyperglycemia at the wound site. Moreover, photocatalytic O2 production represents a promising strategy for addressing chronic bacteria‐infected diabetic wounds. [ABSTRACT FROM AUTHOR]

Machine learning potential energy functions can drive the atomistic dynamics of molecules, clusters, and condensed phases. They are amongst the first examples that showed how quantum mechanics together with machine learning can predict chemical reactions as well as material properties and even lead to new materials. In this work, we study the behaviour of tungsten trioxide (WO3) surfaces upon particle impact by employing potential energy surfaces represented by neural networks. Besides being omnipresent on tungsten surfaces exposed to air, WO3 plays an important role in nuclear fusion experiments due to the preferred use of tungsten for plasma-facing components. In this instance, the formation of WO3 is caused by the omnipresent traces of oxygen. WO3 becomes a plasma-facing material, but its properties, especially concerning degradation, have hardly been studied. We employ molecular dynamics simulations to investigate sputtering, reflection, and adsorption phenomena occurring on WO3 surfaces irradiated with Argon. The machine-learned potential energy function underlying the MD simulations is modelled using a neural network (NNP) trained from large sets of density functional theory calculations by means of the Behler–Parrinello method. The analysis focuses on sputtering yields for both oxygen and tungsten (W), for various incident energies and impact angles. An increase in Ar incident energy increases the sputtering yield of oxygen, with distinct features observed in different energy ranges. The sputtering yields of tungsten remain exceedingly low, even compared to pristine W surfaces. The ratios between the reflection, adsorption, and retention of the Ar atoms have been analyzed on their dependence of impact energy and incident end angles. We find that the energy spectrum of sputtered oxygen atoms follows a lognormal distribution and offers information about surface binding energies on the WO3 surface. [ABSTRACT FROM AUTHOR]

In the contemporary landscape of technological advancements, the burgeoning demand for portable electronics and flexible wearable devices has necessitated the development of energy storage systems with superior volumetric performance. Tungsten oxide (WO3), known for its high density and theoretical capacitance, is a promising electrode material for supercapacitors. However, low conductivity and poor cycling stability are still the key bottlenecks for its application. Herein, a novel composite comprising hollow porous WO3 spheres (HPWS) derived by template method was electrostatic self-assembled on the surface of the Ti3C2T x nanosheets. The resulting electrodes exhibited ultra-high volumetric capacitance of 1930 F cm−3 at 1 A g−1 and rate capability of 46% at 50 A g−1, attributed to enhanced ion accessibility from microporous structure and electron transport from conductive network of Ti3C2T x even at a high packing density of 3.86 g cm−3. Utilizing HPWS/Ti3C2T x as the negative electrode and porous carbon as the positive electrode, the assembled asymmetric supercapacitor achieved an energy density of 31 Wh kg−1 at a power density of 650 W kg−1 with over 107% capacitance retention after 5000 cycles. This work provides a promising approach for developing next-generation supercapacitors with ultra-high volumetric capacitance. [ABSTRACT FROM AUTHOR]

Hydrosols containing tungsten(VI) oxide nanoparticles have been studied by the electrooptical and electrophoretic methods. The influence of multivalent ions (tetravalent thorium and trivalent lanthanum cations) on the zeta-potential and polarizability of tungsten(VI) oxide particles has been determined. The dispersion dependences of the polarizability of tungsten(VI) oxide particles have been studied. A strong dependence of the electrokinetic potential and a weak dependence of the polarizability of the particles on the concentrations of thorium and lanthanum cations in the sols have been found. The polarizability of the particles is low and weakly depends on the frequency of the field polarizing the particles. This is atypical for colloidal particles, for which the thickness of the dense part of the electrical double layer is comparable with the size of molecules, while the polarization of the electrical double layer is determined by its diffuse part. The obtained results have led to a conclusion that, for tungsten(VI) oxide particles in the studied concentration range, the majority of multivalent counterions are located in the dense part of the electrical double layer due to their high adsorption potential. [ABSTRACT FROM AUTHOR]

Semiconducting metal oxide-based gas sensors are an appealing option for numerous applications, including as air quality monitoring and for the detection of hazardous gases in the environment. We report a fabrication of highly stable tungsten oxide (WO3) based humidity sensor using a simple hydrothermal method. The morphological analysis reveals the formation of sheets like nanostructures of average size ~ 1.35 μm and thickness ~ 160 nm and the structural analysis reveals the monoclinic crystal structure of WO3. The 3.53 eV bandgap of WO3 nanostructures, determined by optical analysis using the Tauc equation, significantly enhances charge transfer properties. The Fourier transform-infrared spectroscopy (FTIR) spectra of all bands associated with the formation of WO3. Energy Dispersive X-ray Spectroscopy(EDS) identified tungsten and oxygen components. In Raman analysis the bands at 711.08 cm− 1 and 801.41 cm− 1 correspond to the monoclinic phase of WO3 (W-O-W stretching mode). The sensor shows higher response, ~ 112.5, for the relative humidity of ~ 90% in addition to fast response and recovery time of 33 and 9 s, respectively. The enhanced humidity response from the fabricated sensor is due to the high surface area of the nanostructures which enables the adsorption of large amount of water molecules through the physisorption process. Overall, the designed WO3-based chemi-resistive sensors provides its strong humidity sensing capability at an ambient condition. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) thin films were deposited on glass substrates of Corning glass (CG) and fluorine-doped tin oxide (FTO) using an RF magnetron sputtering process. The effects of varying the annealing temperature on structural, surface morphology, optical properties, and electrochromic (EC) are examined using X-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), SEM, Raman spectroscopy, UV-Vis spectroscopy, and cyclic voltammetry. WO3 thin films annealed at 573 K and 673 K were shown by SEM analysis to have fewer cracks after being found to crack more at 773 K. According to the XRD investigation, the WO3 thin films annealed at 573 K, 673 K, and 773 K had a crystalline nature. At 773 K, when the coloring efficiency (CE) was determined to be 40.45 cm2/s, the diffusion coefficient was found to be the lowest (1.7 × 10−14 cm2/C). At 573 K, the coloring efficiency (CE) was measured to be 52.38 cm2/C, and at 673 K, it was 39.33 cm2/C. It has been discovered that post-annealing significantly affects color efficiency, which is important in electrochromic (EC) applications. [ABSTRACT FROM AUTHOR]