WO3 Nanoparticles Research Articles

Phytomediated synthesis of WO3 nanoparticles using Solanum lycopersicum fruit extract for enhanced photocatalytic activity of 2,4-dichlorophenol

ABSTRACT In the present study, bio-citric acid/tungsten oxide (WO3) (BCAWO) nanoparticles (NPs) were prepared by using Solanum lycopersicum fruit extract as a reducing as well as a capping agent. The photocatalysts were characterized by UV–vis diffuse reflection spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy, and photoluminescence spectroscopy techniques. Diffraction peaks in the XRD spectrum were identified as the crystal planes of crystalline tungsten oxide. The BCAWO had an average size of 23.14 nm. For W–O bonds, the Fourier transform infrared spectrum displays the vibrational peak at 671.23 cm−1. A prominent absorption band was observed at 268 nm, indicating the 1.2 eV bandgap. Under xenon (Xe) lamp irradiation, the synthesized BCAWO nanoparticles showed notable photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP), with a degradation rate of 96%. With BCAWO concentrations of 2.5 g/L, pH of 4, reaction period of 180 min, and 2,4 DCP concentration of 10 mg/L, the degradation of 2,4-DCP had the highest efficacy, 96%. The degradation of phenols in wastewater may be facilitated by using the green WO3 nanoparticles as a photocatalyst, according to the results.

MXene/WO3 Sensor Array with Improved SNN Algorithm for Accurate Identification of Toxic Gases.

Gas sensing is pivotal in critical areas such as industrial production and food safety. This study explores the gas classification capabilities of MXene-based gas sensors. Pure V2CTx MXene and an MXene/WO3 nanocomposite were synthesized, and MXene-based gas sensors were integrated into a 2 × 2 rudimentary electronic nose array. The tests on gas sensitivity revealed that the inclusion of WO3 nanoparticles (NPs) boosted the sensor's response to 10 ppm of NO2 from 2.82 to 3.45 at room temperature. Moreover, the sensor showcased a rapid response/recovery duration of 74.5/149.0 s, excellent environmental stability, and long-term reliable sensing performance. Furthermore, we have improved the method of accurately identifying four toxic gases detected by an MXene-based sensor array using a spiking neural network (SNN) based on the memristive system. Also, the performance of this identification method revealed that the method achieved 95.83% accuracy in the identification of the four gases. Notably, the improved SNN demonstrated approximately 5% higher accuracy than the other gas recognition algorithm. These results highlight the potential of SNN as a powerful tool to accurately and reliably identify toxic gases based on the gas sensor array.

Investigation of UV-blocking and photon-down conversion characteristics of PMMA@ CH3NH3PbBr3:WO3 polymer nanocomposites

Herein, methyl ammonium lead bromide: Tungsten trioxide (CH3NH3PbBr3:WO3) nano heterojunction and polymethyl methacrylate (PMMA) polymer composite films of different weight percentage (wt%) proportions of CH3NH3PbBr3:WO3 nanoparticles (0, 0.5, 1.0, 1.5 and 2.0 wt%) were prepared. The structure, morphology and thermal features of CH3NH3PbBr3:WO3 heterojunctions and PMMA@CH3NH3PbBr3:WO3 nanocomposites were investigated using X-ray diffraction (XRD), Fourier Transform-Infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM) and Differential scanning calorimetry (DSC) techniques. The characterization data revealed decrease in crystallinity (up to 7.97%) and glass transition temperature (Tg) with increase in the concentration of CH3NH3PbBr3:WO3 nanoparticles in PMMA nanocomposites. The UV-visible absorbance and transmittance data of PMMA nanocomposites recorded using UV-visible spectroscopy was used to mathematically deduct the optical characteristics such as absorption coefficient, optical band gap, refractive index, extinction coefficient, finesse coefficient, optical conductivity and Urbach energy. The deducted data revealed improved UV-shielding, refractive index and optical conductivity values while the optical band gap and Urbach energy was found to decrease with concentration of dopant. The experimental data of different PMMA@CH3NH3PbBr3:WO3 composite films showed excellent UV- blocking properties in the wider wavelength range of 259-322nm(4.80eV-3.850eV). The PMMA nanocomposites with 2.0 wt% CH3NH3PbBr3:WO3 filler composition exhibited highest UV-shielding behavior with maximum UV-absorption in the wavelength range of 260 to 300nm. The pristine PMMA films showed a PL emission peak at 410nm while the PMMA nanocomposites exhibited strong emissions in the wavelength range of 485-520nm. The observed hydrophobicity, redshift and longer lifetime decay of 34.3 ns for PMMA nanocomposites is attributed to the incorporated CH3NH3PbBr3:WO3 heterojunction nanoparticles. The chromaticity profile suggested that the emission color changed from blue to green as the filler dose of CH3NH3PbBr3:WO3 varied from 0 to 2.0 wt%. Additionally, the findings from the study reveal that incorporation of CH3NH3PbBr3:WO3 into the PMMA matrix enhances UV-absorption, optical conductivity, hydrophobicity, thermal stability, electrical conductivity and photon-down conversion properties of PMMA which make the material suitable for photonic, photovoltaic, optoelectronic and light emitting diode applications.

Advancing gamma radiation shielding with Bitumen-WO₃ composite materials

This research focuses on a manner in which bitumen-WO₃ (petroleum-derived bitumen mixed with tungsten trioxide nanoparticles) materials can be a good shielding candidate against gamma radiation. The objective we set in mixing WO₃ nanoparticles with bitumen was to take advantage of both the bitumen's natural qualities and the WO₃'s excellent shielding capabilities. The prepared composites were tested against various gamma-ray energies emitted from multiple gamma-ray sources to examine their shielding capabilities. The X-ray diffraction (XRD) analysis of the composites' structural properties verified the effective integration of the WO₃ with the bitumen structure. Scanning electron microscopy (SEM) showed that microstructural changes, such as an increase in material density and an improvement in particle dispersion, are caused by a rise in WO3 concentration, which is an essential step toward efficient shielding. Then, the Mean Free Path (MFP), Half-value Layer (HVL), and Linear Attenuation Coefficients (μl) were computed, showing that the composite's capacity to reduce gamma radiation is much enhanced by raising the WO₃ content, especially at lower gamma-ray energies. For instance, at 20 keV, the LAC of 50 wt% WO₃-bitumen composite increased to 9.18 cm⁻1 compared to pure bitumen's 0.40 cm⁻1, while the HVL decreased from 1.73 cm to 0.08 cm, and the MFP dropped from 2.3 cm to 0.1 cm” The results demonstrate the potential of bitumen-WO₃ composites as a sustainable and efficient material for radiation shielding, particularly highlighting their applicability in various sectors, including the development of building wall paints against gamma radiation.

Structural, optical, photocatalytic and thermal behaviour of (Nb, Ta) co-doped WO3 nanoparticles and its application in photocatalytic degradation of MG and RhB dyes

In this communication, eco-friendly, cost effective and facile hydrothermal route was adopted to synthesize pure WO3, Nb-doped WO3 and (Nb, Ta) co-doped WO3 nanoparticles. Phase, lattice constants, crystallite size and crystallinity have been evaluated through X-ray diffraction. The insertion of Nb and Ta ions into WO3 nanoparticles was confirmed by XPS, FTIR and EDS studies. HRTEM and SAED micrographs exhibited highly nanocrystalline nature of samples. UV–visible studies was carried out to analyse nature of band gap, band gap energy, extinction coefficient, refractive index, Urbach energy and optical conductivity of prepared samples. Optical band gap was narrowed from 2.94 to 2.49 eV and Urbach energy was extended from 0.08 to 0.35 eV through co-doping of (Nb, Ta) ions into WO3 NPs. Reduction in PL intensity revealed that electron-hole pair recombination rate was decreased with co-doping of (Nb, Ta) ions. The photo-degradation efficiency of (Nb 5 %, Ta 5 %) co-doped WO3 nanophotocatalysts was 93.12 % against MG and 90.11 % against RhB dyes. The rate constant was found to be increased from 0.0107 to 0.0203 min−1 for MG and 0.0086 to 0.0174 min−1 for RhB. Thermal results exhibited the weight loss in three phase degradation processes, and thermal stability. The results showed that (Nb 5 %, Ta 5 %) co-doped WO3 NPs is a potential candidate for practical applications in environmental remediation (organic dyes degradation).

Mass-Producible Transparent Flexible Passive-Cooling Film.

Passive cooling is regarded as the desired method for interior temperature regulation due to its advantage of energy consumption reduction. An ideal passive-cooling window is expected to exhibit a high emissivity in the mid-infrared (MIR, 8-13 μm) spectral range for cooling and a low transmittance in the near-infrared (NIR, 780-2100 nm) spectral range for reducing heat flow, while presenting a high transmittance in the visible (VIS, 400-780 nm) spectral range for daylighting. However, material structures that meet these requirements often come with high demands for precision in manufacturing and elevated processing costs, which have limited their potential for large-scale mass production. Here, we propose a mass-producible transparent flexible passive-cooling film that is relatively easy to process and low-cost and meets all of the requirements mentioned above. The film is made of poly(methyl methacrylate) mixed with Cs0.33WO3 nanoparticles, and it shows a high absorptance (80%) in NIR for blocking solar radiation penetration and a high emissivity (93%) in MIR for radiative cooling as well as a reasonable transmittance (40%) in VIS for visibility. Under solar intensity of ∼900 W/m2, a maximum temperature reduction of 8.4 and 7.8 °C has been achieved for a window coated by the film compared to the uncoated window in the condition of the absorbing chamber and car, respectively. Such a mass-producible transparent flexible passive-cooling film holds promising applications in large windows, such as those used in automobiles and buildings, where there is a high demand for both daylighting and cooling.

Composites Based on Electrodeposited WO3 and TiO2 Nanoparticles for Photoelectrochemical Water Splitting.

Photoelectrochemically active WO3 films were fabricated by electrodeposition from an acidic (pH 2), hydrogen-peroxide-containing electrolyte at -0.5 V vs. SCE. WO3-TiO2 composites were then synthesized under the same conditions, but with 0.2 g/L of anatase TiO2 nanoparticles (⌀ 36 nm), mechanically suspended in the solution by stirring. After synthesis, the films were annealed at 400 °C. Structural characterization by XRD showed that the WO3 films exhibit the crystalline structure of a non-stoichiometric hydrate, whereas, in WO3-TiO2, the WO3 phase was monoclinic. The oxidation of tungsten, as revealed by XPS, was W6+ for both materials. Ti was found to exist mainly as Ti4+ in the composite, with a weak Ti3+ signal. The efficiency of the WO3 films and composites as an oxygen evolution reaction (OER) photo-electrocatalyst was examined. The composite would generate approximately three times larger steady-state photocurrents at 1.2 V vs. SCE in a neutral 0.5 M Na2SO4 electrolyte compared to WO3 alone. The surface recombination of photogenerated electron-hole pairs was characterized by intensity-modulated photocurrent spectroscopy (IMPS). Photogenerated charge transfer efficiencies were calculated from the spectra, and at 1.2 V vs. SCE, were 86.6% for WO3 and 62% for WO3-TiO2. Therefore, the composite films suffered from relatively more surface recombination but generated larger photocurrents, which resulted in overall improved photoactivity.

Tungsten based nanostructured hybrid electrocatalysts in neutral medium for hydrogen evolution reaction

Generating a clean and sustainable hydrogen using the naturally available electrocatalysts to split water is among the primary energy resources adopted by the global industries. Transition metal dichalcogenides such as tungsten disulfide (WS2) provide abundant active sites to foster hydrogen evolution reaction (HER). A simple hydrothermal process was employed to synthesize WO3·H2O (hydrated tungsten trioxide) and WO3 nanoparticles. The inclusion of WS2 into the oxide has enhanced the ionic movement, which has improved the catalytic performance of the composite. The hydrophilic nature of WO3 has facilitated the conversion of water molecules into adsorbed hydrogen, which was then spilled over the HER active sites of WS2 to produce hydrogen. Thus, the WO3·H2O/WS2 catalyst achieved a current density of 10 mA cm−2 at an overpotential of 383 mV with Tafel slope of 77 mV dec−1 under neutral conditions and a hydrogen evolution rate of 0.33 mmol h−1 cm−2 at −0.5 V versus RHE.

Polymer-stabilized cholesteric liquid crystals with multi-state reversibility for applications in advanced smart adjustable anti-counterfeiting and energy-saving displays

The creation of an anti-counterfeiting material with reflection color, fluorescence, infrared imaging, and electrical property information will increase the level of anti-counterfeiting. However, the creation of such a material has proved to be extremely challenging. In this study, twin anti-counterfeiting labels with intelligently tunable patterns were obtained through a strategy of PMMA loaded chiral molecules via diffusing on the micrometer scale. In order to enhance anti-counterfeiting ability, the multi-mode intelligently modulated advanced anti-counterfeiting material was obtained through the strategy of introducing photo-isomerizing dithienylethene and infrared-shielding Cs0.33WO3 nanoparticles. This material can be reversibly converted into fluorescent, reflected colors, infrared, and electrical characteristic signals. The encrypted information is displayed with red fluorescence under UV light irradiation. Furthermore, the encrypted information can be reversibly displayed and erased under repeated stimulation by voltage and pressure, heating and cooling, UV, visible and near infrared (NIR) light. The aim of our work is to create a simple method to prepare complex patterns of structural and fluorescent color anti-counterfeiting films with the improved anti-counterfeiting capability. Based on this, the strategy of co-doping fluorescent molecules and photochromic molecules in liquid crystals combined with etching technology has realized a multiple anti-counterfeiting mode with a higher level of security. The advanced multiple anti-counterfeiting mode can output encrypted information of multiple states which will greatly improve the level of anti-counterfeiting. In terms of display, we obtained billboards with complex patterns, price intelligently tunable and full-color display by diffusion S5011 in liquid crystals, thus extending their application in the field of electronic shelf labels.

Facile synthesis of ultrafine WO3 nanoparticles for highly sensitive acetoin biomarker gas detection

Facile synthesis of metal oxide semiconductors (MOSs) nanoparticles with ultrafine size is quite promising to improve gas sensing performance due to the large effect of the particle size on the electron depletion layer (EDL), however, which is currently difficult to realize. In this work, we synthesized ultrafine WO3 nanoparticles of 20 ∼ 30 nm via room-temperature hydrolysis with following annealing and investigated the gas sensing performance of the WO3 nanoparticles towards acetoin biomarker released by Listeria monocytogenes (LMs). The WO3 gas sensor displays high response (Ra/Rg = 32.0@5 ppm), excellent selectivity and low detection limit at 140 °C. The ultrafine size of WO3 comparable to its Debye length can lead to a larger variation of EDL thus a higher sensor response. Our work has provided a facile, low cost and large-scale synthetic route to constructing high-performance acetoin biomarker gas sensors and might contribute to the development for LMs detection.

Oxalic acid capped tungsten oxide nanozyme mimicking peroxidase activity, its synthesis characterization, and kinetic data validation via spectrophotometric studies

The need for parody enzymes has attracted the interest of researchers globally. Nanomaterials have provided promising results as mimic catalysts termed nanozymes (NZMs). This article briefs the peroxidase mimicking behavior of Oxalic acid-capped WO3 nanoparticles (Ox-WO3 NPs), which were hydrothermally synthesized. The peroxidase parodying behavior of the synthesized NZMs was studied for H2O2 as substrate and PPDD-NEDA and TMB as a chromogenic reagent in Phosphate buffer at pH 6.5. The coupled product of PPDD-NEDA showed λmax=480 nm, and the method was linear between 0.2413 and 1.93 mM. The oxidized product of TMB λmax=650 nm was linear in the range of 0.1938–1.9386 mM. Km values corresponding to TMB, and PPDD-NEDA were 0.5308 and 0.3957 mM. Kinetic constants with respect to PPDD-NEDA i.e., Vmax, Kcat, Keff, and Kpow were found to be 0.1913 mM/min, 3.3639 min−1, 8.4999 mM−1 min−1, and 0.4833 min−1. The precision study for intra-day (1.27–2.49 %) and inter-day (1.09–1.52 %) has been calculated. LOD and LOQ of the reaction was found to be 56.34 and 170.73 µM respectively. Characterization of synthesized NPs were carried out with respect to morphology, crystallinity, size, zeta potential and others. The XRD of the sample revealed the crystallite size to be 42.6 nm (Williamson-Hall equation) and 35 nm (Scherrer equation), Crystal structure was identified to be a mixture of monoclinic and orthorhombic as compared with the JCPDS file and the crystallinity of the sample was found to be 79.75 %. The SEM images provided the morphology to be spherical in nature with more aggregation due to lower zeta potential value as recorded by the DLS. The elemental composition by EDS recorded the formation of WO3 NPs. The broad peak of FT-IR spectra between 2900 and 3900 cm−1 confirms the capping of oxalic acid to WO3 NPs.

Influence on the effect of Gd rare earth doped WO3 nanoparticles for enhanced photocatalytic and antibacterial activities: A nanoplate like morphology

Optimizing the photocatalytic antibacterial properties of nanomaterials by defect engineering is becoming a significant tool. The synthesis and characterization of Gd- doped tungsten oxide (Gd:WO3) nanoparticles for potential applications in wastewater treatment and antibacterial activity. Synthesis of the Gd:WO3 nanoparticles were prepared using the co-precipitation method, known for its simplicity and cost-effectiveness in producing nanomaterials. Samples were characterization by XRD confirmed the monoclinic crystal system of all samples and the incorporation of Gd ions into the WO3 lattice. SEM and TEM revealed a nanoplate-shaped morphology of the synthesized nanostructures. EDS confirmed the composition of Gd:WO3. FT-IR verified the presence of functional groups. XPS investigated the effect of Gd doping on the valence states of Gd:WO3, revealing the location of Gd ions within the WO3 lattice. UV-Vis showed increased absorption in the visible region and a decrease in the band gap with increasing Gd concentration up to 5 wt%, indicating potential photocatalytic properties. The nanoparticles demonstrated significant photocatalytic activity, achieving a 98 % degradation of methylene blue (MB) dye under visible light exposure. Among them, the Gd (5 wt%) nanoparticles exhibited the highest photocatalytic performance within 120 min. Additionally, these Gd (5 wt%) nanoparticles showed the greatest antibacterial effectiveness against Staphylococcus aureus, with an inhibition zone of 20 mm. Moreover, the study demonstrates the potential of Gd-doped tungsten oxide nanoparticles as efficient and environmentally friendly materials for wastewater treatment and antibacterial applications.

Advanced polymeric matrix utilizing nanostructured bismuth and tungsten oxides for gamma rays shielding

In this study, the shielding properties of novel polymer composites, developed by integrating glycidyl methacrylate with nanoparticles of bismuth oxide (Bi2O3) and tungsten oxide (WO3), were explored. The ability of the composites to attenuate gamma radiation was evaluated by measuring the emissions from Ba-133, Co-60, Cs-137, and Na-22. X-ray diffraction (XRD) spectra were obtained for both the pure polymer glycidyl methacrylate and the samples containing nanostructures of Bi2O3, Bi2O3/WO3, and WO3, and scanning electron microscopy (SEM) was used to analyze the samples. The incorporation of Bi2O3 and WO3 nanoparticles into the polymer glycidyl methacrylate matrix significantly enhanced the composites' ability to attenuate gamma radiation, as demonstrated by the increased linear and mass attenuation coefficients. The results showed good agreement between the experiment and the XCOM database. The composites exhibited significant efficiency in attenuating lower-energy gamma rays, which is particularly advantageous in the medical and nuclear industries.

Structural, optical and morphological properties of Eu rare earth doped WO3 nanoparticles enhanced photocatalytic for waste water treatment and antibacterial activities

In this paper, summarise the characterization and synthesis of the pure and Eu:WO3 nanoparticles and their applications in photocatalytic and antibacterial activity. The monoclinic phase confirmed by the XRD analysis of the prepared specimens. SEM and HR-TEM scrutiny revealed nanoplate morphology scrutiny. EDS and XPS scrutiny confirmed the composition of elements of Eu, O, and W. FTIR analysis likely used for additional confirmation of functional groups. UV–Vis Analysis determined the band gap energy (Eg) of the nanoparticles, which decreased with raising the concentration of Eu doping. Optical properties of the band gap energy decreased with raising the concentration of Eu doping. Photocatalytic activity of the nanoparticles exhibited high photocatalytic activity, with a 95.3 % methylene blue (MB) dye split when exposed to visible light. The Eu:WO3 (7 wt%) nanoparticles showed the best photocatalytic property within 120 min. The Eu:WO3 (7 wt%) nanoparticles showed the maximum antibacterial efficiency against Staphylococcus aureus, with a zone of embarrassment of 19 mm. Overall, the study demonstrates the successful synthesis of Eu-doped WO3 nanoparticles and their potential applications in photo catalysis and antibacterial activity, with promising results particularly at higher Eu doping concentrations.

Localized nitride strategy to construct interfacial and electronic modulated WO3/WN nanoparticles for superior lithium-ion storage

The interfacial effect is important for the tungsten trioxide (WO3)-based anode to achieve superior lithium-ion storage performance. Herein, the interfacial effect was constructed by in-situ surface direct nitridation reaction at 600 ℃ for 30 min of the as-synthesis WO3 nanoparticles (WO3/WN). X-ray photoelectron spectroscopy (XPS) analysis confirms evident chemical interaction between WO3 and WN via the interfacial covalent bond (WON). This WO3/WN anode shows a distinct interfacial effect for an efficient interatomic electron migration. Electrochemical kinetic analysis shows enhanced pseudocapacitance contribution. The galvanostatic intermittent titration technique (GITT) result demonstrates improved charge transfer kinetics. Ex-situ X-ray diffraction (XRD) analysis reveals the reversible oxidation and reduction reaction of the WO3/WN anode. The density functional theory (DFT) result shows that the evident interfacial bonding effect can enhance the electrochemical reaction kinetics of the WO3/WN anode. The discharge capacity can reach up to 546.9 mA h g−1 at 0.1 A g−1 after 200 cycles. After 2000 cycles, the capacity retention is approximately 85.97 % at 1.0 A g−1. In addition, the WO3/WN full cell (LiFePO4/C//WO3/WN) demonstrates excellent rate capability and capacity retention ratio. This in-situ surface nitridation strategy is an effective solution for designing an oxide-based anode with good electrochemical performance and beyond.

The role of sub-regional electrostatic spinning nanofiber loaded with WO3 nanoparticle in modulating electro-optic performance and stepwise display of polymer dispersed liquid crystal

ABSTRACT The advancement of multi-functional displays with outstanding electro-optical properties is particularly essential at present. However, conventional integral all-area driven transparent displays are gradually failing to meet current demands. Herein, sub-regional electrostatic spinning of nanofibers as a novel fabrication method was introduced into polymer-dispersed liquid crystal (PDLC) to achieve stepwise display in concert with loaded WO3 nanoparticles, addressing the aforementioned drawback. The use of nanofibers played a crucial role in ensuring fine dispersion of nanoparticles, resulting in a reduction of the saturation voltage of the PDLC film from 28.9 V to 19.7 V and an increase in contrast ratio from 105.7 to 194.3. Meanwhile, experimental findings and theoretical considerations have revealed that variations in microscopic pore size can significantly influence the electro-optical behaviour of PDLC film. Next, the stepwise PDLC film was prepared by electrostatically spinning nanofibers onto half of the LC cell region, leading to different voltage-transmittance responses between the two regions. Consequently, under appropriate driving voltages, the PDLC film can realise three different optical states: total scatter, half-transparency, and total transparency. In addition, the PDLC film exhibited excellent anti-thermal ageing performance, allowing it to excel in various advanced display applications.

NH2-MIL-125(Ti-Zr) synergized with WO3 to construct S-Scheme heterojunction photocatalysts for highly efficient degradation of organic dyes and tetracycline in water

The rapid treatment of organic dyes and tetracycline (TC) in industrial wastewater requires highly efficient semiconductor photocatalysts. In this study, the S-Scheme NH2-MIL-125 (Ti-Zr)/ WO3 composite material was successfully synthesized using a two-step hydrothermal method. A comprehensive analysis using X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HRTEM), and Field Emission Scanning Electron Microscopy (FESEM) images revealed that WO3 nanoparticles are intimately anchored on the NH2-MIL-125 (Ti-Zr) nanodisks, forming a closely packed heterostructure. The bandgap values of WO3 and NH2-MIL-125 (Ti-Zr) were determined to be 2.58 eV and 2.67 eV, respectively. Through Response Surface Methodology (RSM), the optimal photocatalytic conditions for the degradation of simulated pollutants in real aqueous environments by the synthesized photocatalysts were explored. Under the full-spectrum irradiation of a 300 W xenon lamp, the TZW-2 composite photocatalyst exhibited a degradation rate of RhB, MB, and TC solutions as high as 95.7 %, 96.7 %, and 93 % within 90 min, respectively. The excellent photocatalytic performance of the composite photocatalyst originates from the establishment of S-scheme heterojunctions between NH2-MIL-125 (Ti-Zr) and WO3, which was confirmed by various characterization techniques such as XPS valence spectra, photoelectrochemistry, and free radical trapping experiments. The excellent stability of the prepared composite photocatalyst was further validated through three cycling test experiments. This work presents new ideas for constructing novel S-Scheme photocatalysts by combining bimetallic cluster MOFs and metal oxides for wastewater treatment.

The impact of laser pulses on the optical and structural characteristics of WO3 nanoparticles fabricated via laser ablation in liquid (PLAL)

The impact of laser pulses on the optical and structural characteristics of WO3 nanoparticles fabricated via laser ablation in liquid (PLAL)

Reversibly photochromic wood constructed by electric field-assisted self-assembled chitosan and tungsten trioxide coatings

ABSTRACT The photochromic properties are highly desirable for advanced wood applications, but they have not been extensively studied. To incorporate photochromic capabilities into wood materials, composite coatings were developed on the wood surface using an electric field-assisted layer-by-layer (LBL) self-assembly technique. The composite coatings consist of cationic chitosan and anionic tungsten trioxide (WO3) nanoparticles. By applying a direct current voltage during the deposition process, a well-organized distribution of WO3 nanoparticles was achieved, resulting in a uniform coverage of the wood substrate. This assembly process facilitated the creation of structured photochromic coatings with minimal nanoparticle fillers, a straightforward and rapid procedure, and potential for large-scale production. Lab colorimetric results demonstrated that the wooden substrate changed color from its natural state to blue when exposed to UV light. UV-vis spectroscopy further confirmed the efficient absorption of WO3 and photochromic properties of the modified wood.

Enhanced hydrogen gas sensing performance with Ag-doped WO3 thin film

The paper reports the fabrication of a device, based on the thin film of Ag-doped WO3 nanoparticles, to enhance the hydrogen gas sensing performance. The synthesis of thin films of pristine and Ag-doped WO3 nanoparticles were carried out using the single-step hydrothermal method, followed by the spin coating deposition process. The characterization of the samples was carried out with XRD, FESEM, TEM, FTIR and UV–vis spectroscopy. The consistent pattern observed from the microstructure analysis of data from XRD, UV–vis spectrometer and FTIR validates effective incorporation of Ag into the WO₃ structure. The XRD patterns confirmed the formation of the monoclinic phase of WO3 nanoparticles. The crystallite size and the value of band gap decreased on increasing the Ag doping percentage in WO3. This reduction with Ag-doping could be attributed to the proper substitution of the W with Ag due to their similar sizes. The gas sensing performances of the fabricated sensing devices were analyzed by exposing different concentrations of hydrogen gas ranging from 12.5 ppm to 75 ppm. The device based on the thin film of Ag-doped WO3 performed much better than the device based on the thin film of pristine WO3 nanoparticles. The device with 4% Ag-doped WO3 showed the best sensor response of 98 % for 75 ppm H2 gas concentration with response and recovery time of 76 and 100 s, respectively at 100 °C. The improved response of the device with Ag doping compared to the pristine device could be attributed to the better charge transfer, more defect creation, and the ability of Ag to work as a catalyst to make reaction kinetics faster. The selectivity of the device was tested using the oxidizing and reducing gasses of NO2, H2, and NH3 at 100 °C for 75 ppm gas concentration. The recorded response of the device for NO2, H2, NH3 were 38%, 98%, and 43%, respectively.