Pure WO3 Research Articles

Biosynthesis of Zr-doped WO3 Nanoparticles: Evaluation of Antibacterial, Antioxidant, and Enzymatic Activities

Herein, biocompatible pure tungsten oxide (WO3) and zirconium-doped tungsten oxide (Zr-doped WO3) nanoparticles (NPs) were prepared via a green approach from moringa plants with different doping concentrations (3, 5, and 7%). The as-synthesized materials were morphologically and optically characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and ultraviolet-visible (UV-Vis) spectroscopy. The FTIR spectra clearly showed that two distinguishing bands at 603 and 674 cm-1 of WO3 were shifted to a higher wavenumber upon doping with zirconium. EDX analysis confirmed the successful synthesis of pure WO3 and Zr-doped WO3 by the green approach. The UV-Vis study exhibited that the bandgap of pure WO3 is blue-shifted upon Zr doping due to the Burstein-Moss effect. The XRD pattern revealed that the crystalline nature of WO3 is increased by increasing the Zr content. Further, the as-synthesized materials were evaluated for enzymatic, antibacterial, and antioxidant activities. The enzymatic results showed that 7% of Zr-doped WO3 NPs have a higher activity for the α-amylase enzyme. Additionally, 7% Zr-doped WO3 also showed better antioxidant activity, up to 85% for free radical scavenging. The antibacterial performance of 7% Zr-doped WO3 is higher as compared to other corresponding samples for different strains of bacteria. These results demonstrated that this facile and novel synthetic route will open a new door for designing an efficient nanomaterial for biomedical applications.

Efficient Electrochromic Electrode Materials Based on WO3/Ni(OH)2 with Dual Ion Implantation Modulability and Energy Level Matching

AbstractElectrochromic materials have received a lot of attention due to dramatic growth of the smart window market and the demand in various emerging fields. In this study, WO3/Ni(OH)2 composite high efficient electrochromic electrode materials are prepared by hydrothermal‐annealing and electrodeposition methods. It is observed by experimental characterization that the deposition of Ni(OH)2 on WO3 rods effectively increased the Li+ diffusion rate of WO3 films (2.069 × 10−10 cm2 s−1), which is ≈1.5 times higher than that of pure WO3 (1.413 × 10−10 cm2 s−1). Meanwhile, WO3 and Ni(OH)2 have relatively matched energy level structures, showing high overall optical modulation performance. In addition, density functional theory (DFT) calculations combined with electrochemical studies reveal that the injection of double ions can improve the reaction efficiency of the electrodes and promote the redox reaction, which makes the electrochemical reaction more efficient. This paper provides a practical method for designing multi‐component electrochromic devices with excellent performance.

Advances on Tungsten Trioxide Based Additive Materials: Strategies to Fabricate Photocatalytic Membranes for Wastewater Treatment

Due to their ability to combine the physical separation of membrane filtration with organic degradation in one unit, photocatalytic membranes have demonstrated enormous potential for application in energy-efficient water purification and wastewater treatment. Titanium dioxide (TiO2) is the substance most frequently utilized to create photocatalytic membranes. However, TiO2's use is constrained by its substantial band gap (3.2 eV). On the other hand, tungsten trioxide (WO3) has a fairly small band gap (2.7-2.8 eV) which makes it able to absorb visible light, making the photocatalytic process more efficient. This article examines recent developments in WO3 photocatalytic membranes for wastewater treatment and water purification with a focus on the photocatalytic mechanism, photocatalytic membrane fabrication and development. The mechanism of WO3 semiconductor in pollutant removal is explained in detail. Blending, coating and grafting methods, which are three methods commonly used when fabricating photocatalytic membranes, are discussed. Likewise with the development of WO3 photocatalytic membranes using pure WO3, heterojunction or doping with metal.

High-Performance Electrochromic Devices Composed of Niobium Tungsten Oxide Films

Electrochromic technology plays a pivotal role in various industries, offering significant benefits in energy efficiency and sustainability. By efficiently modulating sunlight, it reduces dependence on traditional climate control systems, thus decreasing overall energy consumption. Among electrochromic materials, tungsten oxide (WO3) is highly favored for its outstanding stability and superior optical modulation amplitude. However, the escalating demands of commercial applications necessitate enhancements in electrochromic performance, achievable through doping or composite designs. This study investigates the electrochromic characteristics of novel niobium tungsten oxide (Nb18W16O93) thin films, employing a gel electrolyte and examining their structural, optical, and electrochemical attributes. Compared to pure WO3, the Nb18W16O93-based electrochromic device exhibited a significant optical modulation of 55.1% in the visible spectrum and 31.3% in the near-infrared region. The gel-based device not only provides safety benefits over liquid electrolytes by mitigating leakage risks but also features rapid switching response times, with a coloration duration of 3.9 s and a bleaching interval of 3.6 s. Moreover, the device showcases exceptional long-term stability, retaining a ΔT of nearly 72% after 10,000 cycles.

Facile one-step synthesis of a WO3/ZnWO4 heterojunction modified using ZnFe LDH enhances the PEC water splitting efficiency.

Photoelectrochemical water splitting represents a promising approach for directly converting solar energy into green hydrogen, offering a potential solution to the challenges of energy shortages and environmental pollution. In this work, a WO3/ZnWO4 binary heterojunction was synthesised by a simple and effective one-step drop casting method to enhance the charge separation efficiency; ZnFe LDH was deposited on the surface of the heterojunction with the aim of accelerating water oxidation and synergising with the heterojunction to enhance the photoelectrochemical performance of the photoanode. The photocurrent density of the WO3/ZnWO4/ZnFe LDH electrode can reach 2.1 mA cm-2 at 1.23 V (vs. RHE). This value is approximately 4 times greater than that observed for pure WO3 (0.53 mA cm-2). The IPCE and ABPE were able to improve by 3.1 times and 6 times, respectively.

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).

Silver doping effect on the electrochromic performance of the WO3 thin films produced by thermal evaporation in vacuum

Ag doped WO3 thin films are successfully fabricated by thermal evaporation method in vacuum as precursor, and then annealed at 450 °C in nitrogen gases atmosphere. Cyclic voltammetry, repeating chronoamperometry, chronocolumetry and optical transmittance are recorded in 1 M LiClO4/propylene carbonate electrolyte. The color of the WO3 thin films changes from transparent to the blue under the applied potential of -1.8 and +1.9 V. XRD studies show that all the films have a polycrystalline structure of WO3. The molecular formation is also confirmed by Raman and X-Ray photoelectron spectroscopy (XPS). The EDS elemental mappings clearly confirm the homogeneous distribution of Ag, W and O elements into the WO3 network. From the optical studies, indirect band gap energy of the WO3 decreases as Ag doping level increases. The best coloration and bleaching times (2.33 and 1.25 s) are obtained for the Ag(2 %):WO3 thin films, compared to the pure WO3 (3.79 and 1.96 s). The produced WO3 films exhibit high reversibility (39.6/69.1 %), high coloration efficiency values (26.3/141.2 cm2/C), and good cycling stability. From the EIS measurements, the charge-transfer resistance is Ag(2 %):WO3 < the pure WO3 < Ag(5 %):WO3 < Ag(8 %):WO3, which means that Ag(2 %):WO3 has the biggest electrochemically active surface area. Electronic energy levels of the pure WO3 and the Ag:WO3 thin films are also given. From the Mott-Schottky studies, it is determined that the donor concentration of the materials is of the order of 1014–1015 cm−3. In the literature, there are very limited studies related to electrochromic thin films by thermal evaporation in vacuum. In this sense, the reported results in this study are promising for the electrochromic applications.

Cu(111)-supported W3Ox clusters: Stoichiometry and symmetry effects on CO2 activation and dissociation

Density functional calculations with dispersion corrections (DFT-D) have been performed to study the adsorption and dissociation of CO2 on W3Ox/Cu(111) inverse catalyst (x = 9 or 6). The W3O9 aggregate adsorbs in several different geometries through the formation of O-Cu bonds, in all the cases taking electronic charge from the metal surface. The reduced W3O6 particle anchors very strongly to Cu by means of W-Cu bonds; in this case, the charge transfer is opposite than for W3O9/Cu yielding the oxide particle positively charged. CO2 is activated on W3O6/Cu(111) at the oxide/metal interface; its dissociation was found to be exothermic and kinetically more favorable than on the pure counterparts, Cu(111) and WO3(001) surfaces. In contrast, CO2 is activated on W3O9/Cu(111) only in the form that is by far the least stable (the one possessing Cs symmetry). Our results suggest that stoichiometry and symmetry of Cu-supported W3Ox clusters play a crucial role in CO2 activation and dissociation. In particular, the mixed W3O6/Cu(111) system appears as a catalyst of great potential for reactions involving CO2 dissociation.

High sensitivity and selectivity of h-BN/WO3 n-n heterojunction to triethylamine at low-temperature

Due to the unique properties of heterojunction interfaces, heterojunction materials have broad application prospects in gas sensors. In this work, a facile and economical two-step synthesis method was employed to fabricate h-BN/WO3 heterojunctions, exhibiting excellent performance in triethylamine (TEA) detection. The results indicate that compared to pure WO3 sensors, h-BN/WO3 sensors exhibit superior TEA sensing capabilities, with an excellent response of 281.45 to 20 ppm TEA at 100 °C, which is 3.4 times higher. Moreover, h-BN/WO3 sensors demonstrate favorable response times, low detection limits, and good stability. These significant enhancements are attributed to the increase in oxygen vacancies and the establishment of heterojunctions between h-BN and WO3. Heterojunctions can regulate the concentration and transport rate of charge carriers, as well as the interface potential barrier, thereby affecting the gas sensing processes. This work may promote the further development of sensing materials and the practical application of WO3 sensors in TEA detection.

Sintering Driven Void Formation in PS@WO3 Core-Shell Composites: A Photodegradation Enhancement Strategy

Background: Polystyrene nanospheres are used as a substrate for the hydrothermal coating of tungsten trioxide (WO3) to form a core-shell composite of PS@WO3. The core-shell structure is used for the next sintering step. This produces porous WO3. The focus of this study is on the role of porous WO3 in enhancing photocatalytic performance. Methods: The hydrothermal method was employed for coating, and the surface morphology, as well as the structural properties of WO3-coated PS spheres, were systematically investigated using SEM and XRD analyses. Additionally, the sintering process was introduced to enhance the material by inducing rupture in the PS sphere core, creating voids that significantly increased the material's surface area. Results: The evaluation of the effect of sintering temperature on photodegradation efficiency highlighted the crucial role of sintering temperature. Un-sintered and 300°C sintered WO3, both having a hexagonal crystalline structure, exhibited superior degradation efficiencies compared to samples sintered at higher temperatures (400°C and 500°C). In particular, the 300°C sintered WO3 outperformed its un-sintered counterpart despite identical crystalline structures. The performance of the PS@WO3 composite was assessed to determine the enhanced role of porous WO3. The porous WO3 obtained, in particular by the sintering of the core-shell PS@WO3 composites at 300°C, showed a remarkable improvement in the degradation efficiency. These composite demonstrated over 95% efficiency within 10 minutes and achieved near complete (100%) degradation for a further 10 minutes, surpassing the performance of pure WO3. It is important to clarify that while the final product was predominantly WO3 after the sintering process, the inclusion of PS served a critical purpose in creating voids during sintering. The PS@WO3 composite structure used as a resource for the preparation of porous WO3, even with a potentially reduced PS composition, has been found to play a significant role in influencing the surface area of the material, and consequently the photocatalytic performance. Conclusion: The study has highlighted the importance of crystalline structure and sintering conditions in optimizing the efficiency of photocatalytic materials. The porous WO3 obtained, in particular by the sintering of the core-shell PS@WO3 composites at 300°C, showed promising potential for applications under UV and visible LED light irradiation. These results provide valuable insights for the development of advanced photocatalytic materials with improved performance, highlighting WO3 as the key contributor to the observed improvements.

Extended Interfacial Charge Transference in CoFe2O4/WO3 Nanocomposites for the Photocatalytic Degradation of Tetracycline Antibiotics.

The large-scale utilization of antibiotics has opened a separate chapter of pollution with the generation of reactive drug-resistant bacteria. To deal with this, in this work, different mass ratios of CoFe2O4/WO3 nanocomposites were prepared following an in situ growth method using the precursors of WO3 and CoFe2O4. The structure, morphology, and optical properties of the nanocomposite photocatalysts were scrutinized by X-ray diffraction (XRD), UV-visible diffuse reflectance spectra (UV-Vis DRS), photoluminescence spectrum (PL), etc. The experimental data signified that the loading of CoFe2O4 obviously changed the optical properties of WO3. The photocatalytic performance of CoFe2O4/WO3 composites was investigated by considering tetracycline as a potential pollutant. The outcome of the analyzed data exposed that the CoFe2O4/WO3 composite with a mass ratio of 5% had the best degradation performance for tetracycline eradication under the solar light, and a degradation efficiency of 77% was achieved in 20 min. The monitored degradation efficiency of the optimized photocatalyst was 45% higher compared with the degradation efficiency of 32% for pure WO3. Capturing experiments and tests revealed that hydroxyl radical (·OH) and hole (h+) were the primary eradicators of the target pollutant. This study demonstrates that a proper mass of CoFe2O4 can significantly push WO3 for enhanced eradication of waterborne pollutants.

One-Step Self-Assembled WO3/rGO Microspheres Photoanode Assembled Efficient Photocatalytic Fuel Cells for Simultaneous Organic Pollutant Degradation and Electricity Generation.

Photocatalytic fuel cells (PFCs) present a promising and environmentally friendly approach to simultaneously treat organic pollutants in wastewater and electricity generation. The development of photoanodes with high light absorption and carrier mobility is essential for enhancing the performance of PFCs but remains challenging. Herein, a one-step self-assembly strategy was adopted to develop flower-like WO3/rGO microspheres for PFC devices. Attributed to the abundant surface-active sites, enhanced light harvesting, and efficient separation of photogenerated charge carriers, the WO3/rGO photoanode demonstrated superior rhodamine B (RhB) degradation rate (90% in 2 h), maximum power density (4.74 μW/cm2), and maximum photocurrent density (0.096 mA/cm2), 1.4, 2.4, and 4.0 times higher than the corresponding pure WO3 photoanode, respectively. Density functional theory (DFT) calculations reveal that the built-in electric field formed between the interface of WO3 and rGO promotes the transfer of photogenerated electrons from WO3 to rGO, thus exerting a significant impact on improving the migration and separation of photoinduced charge carriers. Moreover, by combining experimental and theoretical results, a complete PFC operation mechanism for the PFC system was proposed. This study focuses on the strategy of constructing rGO-doped photocatalysts to enhance the interfacial charge transfer mechanism, providing a promising approach for the development of high-performance photoanodes in PFC systems.

Insight into photocatalytic chlortetracycline degradation by WO3/AgI S-scheme heterojunction: DFT calculation, degradation pathway and electron transfer mechanism

The construction of S-scheme heterojunction with excellent redox ability holds promising prospects for photocatalytic environment remediation. However, the rationally design of the heterojunction interface to achieve efficient charge transfer still faces challenges. In this study, we fabricated a tight-contacted S-scheme heterojunction by in situ anchoring AgI nanoparticles onto WO3 nanoplates. The significant difference in Fermi energy levels between WO3 and AgI results in the formation of a space charge region around the interface and bending of the energy band, facilitating directional migration and spatial separation of charge carriers. This contributes to enhanced generation of superoxide radicals (•O2−) and holes (h+) active species, leading to a significant increase in chlortetracycline (CTC) degradation rate. The apparent rate constant for CTC removal using the WO3/AgI (WA-2) is approximately 15 times higher than that observed for pure WO3. Furthermore, WA-2 exhibits universal degradation effects on tetracycline (TC) and oxytetracycline (OTC). Molecular dynamics (MD) simulation reveals the synergistic adsorption effect of WO3 and AgI on CTC and reactive oxygen species molecules. Based on Fukui function calculation of CTC molecules and degradation intermediates, liquid chromatography-mass spectrometry (LC-MS) analysis, photocatalytic degradation pathway over WO3/AgI was determined to be sequential demethylation followed by dechlorination and decarbonylation. These findings provide valuable insights into high-performance S-scheme heterojunctions interface design and elucidation of pollutant degradation mechanism.

High-performance electrochromic devices composed of niobium tungsten oxide films

Electrochromic technology plays a pivotal role in various industries, offering significant benefits in energy efficiency and sustainability. By efficiently modulating sunlight, it reduces dependence on traditional climate control systems, thus decreasing overall energy consumption. Among electrochromic materials, tungsten oxide (WO3) is highly favored for its outstanding stability and superior optical modulation amplitude. However, the escalating demands of commercial applications necessitate enhancements in electrochromic performance, achievable through doping or composite designs. This study investigates the electrochromic characteristics of novel niobium tungsten oxide (Nb18W16O93) thin films, employing a gel electrolyte and examining their structural, optical, and electrochemical attributes. Compared to pure WO3, the Nb18W16O93-based electrochromic device exhibited a significant optical modulation of 55.1% in the visible spectrum and 31.3% in the near-infrared region. The gel-based device not only provides safety benefits over liquid electrolytes by mitigating leakage risks but also features rapid switching response times, with a coloration duration of 3.9 s and a bleaching interval of 3.6 s. Moreover, the device showcases exceptional long-term stability, retaining a ΔT of nearly 72% after 10,000 cycles.

In Situ Synthesis of Hierarchical Co(CO3)0.5(OH)·0.11H2O@ZIF-67/WO3 With High Humidity Immunity and Response to H2S Sensing.

H2S gas sensors with facile preparation, low detection limits, and high selectivity are crucial for environmental and human health monitoring. However, it is difficult to maintain a high response of H2S gas sensors under high humidity in practical applications. To face this dilemma, a layer-by-layer growth method is applied to in situ prepare a nanostructured Co(CO3)0.5(OH)·0.11H2O/WO3 coated by a hydrophobic hierarchical ZIF-67 as the H2S sensor. This novel composite exhibits excellent humidity immunity without sacrificing the excellent sensitivity and selectivity of H2S. At a low operating temperature of 90°C, a remarkable response value of 1052.3 to 100ppm H2S has been achieved, which is 779 and 9.36 times higher than that of pure WO3 and Co(CO3)0.5(OH)·0.11H2O/WO3, respectively. More importantly, an 82.2% relative response value remains at a high humidity of 75%RH. The sensing mechanisms are investigated using gas chromatography-mass spectrometry (GC-MS), which revealed that the reaction products are H2O and SO2. The high humidity immunity and fast response of the Co(CO3)0.5(OH)·0.11H2O@ZIF-67/WO3 demonstrate the layer-by-layer in situ synthesis method holds the potential application for the development of high-performance WO3-based H2S sensors.

Engineering S-scheme heterojunction MgO/WO3-integrated Graphene photocatalyst for robust detoxification of tetracycline: Mechanistic insight and actual matrix remediation

The widespread usage of pharmaceutical compounds for treating humans and animals has led to substantial environmental harm to living organisms globally. Herein, the engineering of step-scheme (S-scheme) heterojunction composite incorporating a co-adsorbent agent is garnering attention as a promising approach for environmental remediation, owing to its improved redox potential and expanded active surface area. This study is the first to employ a graphene-integrated MgO/WO3 S-scheme heterostructure (denoted as MWG) as a ternary photocatalyst for the disintegration of tetracycline (TCY) under UV light exposure. The results confirmed that the MWG nanocatalyst exhibited a significantly improved photocatalytic activity in the degradation of TCY when contrasted with pure MgO, WO3, and graphene (GRP) nanomaterials. Kinetic investigation elucidated that the detoxification of TCY under optimized circumstances was best described by a pseudo first-order kinetic model with regression coefficients higher than 0.97. The scavenging tests revealed that HO● species are the primary agents involved in the TCY degradation during the photocatalytic process. Trapping experiments, photoelectrochemical techniques, and band structure analysis were conducted to propose the plausible detoxification mechanism via the MWG/UV process. A notable enhancement in the biodegradability of actual wastewater was attained following treatment with the MWG/UV process, resulting in 79.6% and 64.8% COD and TOC elimination, respectively, over a 200 min of reaction time. To sum up, the employment of a graphene-integrated MgO/WO3 S-scheme heterojunction composite under UV light illumination can be considered a novel and effective approach for the remediation of real pharmaceutical effluents in real-world scenarios, attributable to its robust redox capacity, significant stability, economic viability, and heightened efficacy in degradation/mineralization processes.

An excellent triethylamine sensor based on composite nanotube WO3/SnO2

Triethylamine (TEA) is a volatile organic compound, widely used in production and life. But as a strong irritating and flammable gas, it is a serious threat to people's life safety, so the development of high-performance TEA gas sensor is of great significance to human life and production. In this work, pure WO3 and WO3/SnO2 composite nanofibers were prepared by electrospinning method. The morphology and microstructure of the obtained samples were characterized by SEM, XRD, XPS, PL, etc. Then the gas sensitivity of the samples was studied. The results show that both pure WO3 nanofibers and composite nanofibers have good selectivity for TEA. But compared with pure WO3 nanofibers, WO3/SnO2 nanofibers have higher response, faster response/recovery time (14 s/22 s) and better stability. The optimal temperature is 260 °C, 20 °C lower than that of pure WO3 nanofibers, and the response to 100 ppm TEA at this temperature is about 26, which is nearly 1 times higher than that of pure WO3 nanofibers. The improvement of gas-sensitive performance is mainly attributed to the successful construction of heterojunctions to improve electron transport efficiency and the optimization of morphology and structure through the composite.

Interface charge transfer and photoelectrochemical properties of SnS2 nanosheets/WO3 heterojunction

Photoelectrochemical water splitting holds great promise as a technology for converting solar energy into hydrogen fuel. In this study, SnS2 nanosheets were vertically aligned and grown in situ on WO3 substrate using chemical vapor deposition (CVD) to create a SnS2/WO3 heterojunction photoanode. The resulting photoanode was then subjected to various characterizations, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) to examine its morphology and structure. The introduction of SnS2 significantly improved the absorption of visible light and carrier density. At 1.4 V (vs. RHE), the photocurrent density of the SnS2/WO3 heterojunction reached 1.86 mA cm−2, which was three times higher than that of pure WO3. KPFM analysis revealed that charge transfer occurred at the SnS2/WO3 heterojunction interface, under light illumination, electrons are transferred from the conduction band of SnS2 to the conduction band of WO3, forming a type-II heterojunction. This work provides an important reference for the development of efficient photoanodes for photoelectrochemical water splitting.

Au nanoparticles decorated ZnIn2S4/WO3 core-shell heterostructures as highly sensitive and selective ethylene glycol gas sensors

Ethylene glycol (EG) is extensively utilized as anti-freezer and deicer, which would bring potential health risk under unintentional exposures especially with hazardous inhalation of EG aerosols or vapors. In this study, ZnIn2S4 (ZIS)/WO3 core-shell nanofibrous heterostructure loaded with optimized Au nanoparticles (NPs) was prepared for superiorly sensitive and selective EG gas sensing. The ternary Au/ZIS/WO3 heterostructures exhibited an excellent response (Ra/Rg=98.92) to 50 ppm EG, demonstrating an enhancement of 3.5 times compared to the binary ZIS/WO3, and a substantial improvement of 59.5 and 24.1 times compared to pure WO3 and ZIS, respectively. The ternary Au/ZIS/WO3 heterostructures also possessed an extremely low detection limit of 6 ppb, as well as excellent selectivity, repeatability, and long-term stability. This exceptional gas sensing performance can be attributed to its distinctive ternary Au/ZIS/WO3 heterostructures with high specific surface areas. This unique structure not only facilitate the activation of abundant active oxygen species, but also promote the spillover effect of Au and enhance effective electronic distribution, thereby providing more EG adsorption sites, which was confirmed by density functional theory calculation. The synergistic effect arising from the metal-semiconductor interface and the core-shell heterostructure presents a novel avenue for advancing high-performance sensor technologies.

Research on the application of WO3 gas sensor based on noble metals modification in cable fire detection

In the monitoring of cable fire, it is of great significance to be able to conduct early fire warning, which requires that sensors have high sensitivity to the cable vapors at low temperatures. In this study, WO3 thick films modified with Au, Pd, and Pt single or bimetallic nanoparticles were fabricated via magnetron sputtering. Gas sensors utilizing these materials exhibited significant response to the low-temperature vapor emitted by YJV22 and YJY23 cables. Among them, Pd/WO3-20 demonstrated a response value of 20 to the vapor of 81[Formula: see text]C YJV22 cables, marking a remarkable 6.3-fold increase compared to pure WO3, and the response time was 13 s. Similarly, Pt/WO3-10 exhibited a response value of 11.11 to the vapor of 104[Formula: see text]C YJY23 cables, representing a 6.9-fold enhancement over pure WO3 with a response time of 12 s. The heating temperature of cables remains below their critical threshold, indicating that it is in the early stages of cable fires, the findings hold significant implications for early warning systems designed to detect cable fires promptly.