Gas Sensing Characteristics of a WO3 Thin Film Prepared by a Sol-Gel Method

Yano, Mitsuaki; Iwata, Tomoya; Murakami, Satoshi; Kamei, Ryouma; Inoue, Taichi; Koike, Kazuto

doi:10.3390/proceedings2130723

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…Although, understanding gas sensing is critical, many researchers are widely accepted empirical models to obtain gas sensing results through a trial-and-error method. Still, the various deposition methods have been used to construct WO 3 thin films with different morphologies such as thermal evaporation (Li et al, 2017), laser beam ablation (Nishijima et al, 2020), molecular beam epitaxy (Li et al, 2015), electron beam evaporation (Madhuri and Babu, 2016), R.F sputtering (Bose et al, 2018), D.C. sputtering (Horprathuma et al, 2013), Sol-gel technique (Yano et al, 2018), Electrodeposition (Mineo et al, 2020), chemical bath (Wang et al, 2020) and spray pyrolysis (Cho et al, 2013). Each method has a set of parameters to control the morphology of WO 3 thin films.…”

Section: Introductionmentioning

confidence: 99%

Nanostructured WO₃ based gas sensors: a short review

Sriram

Parne

Vaddadi

et al. 2021

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Purpose This paper aims to focus on the basic principle of WO3 gas sensors to achieve high gas-sensing performance with good stability and repeatability. Metal oxide-based gas sensors are widely used for monitoring toxic gas leakages in the environment, industries and households. For better livelihood and a healthy environment, it is extremely helpful to have sensors with higher accuracy and improved sensing features. Design/methodology/approach In the present review, the authors focus on recent synthesis methods of WO3-based gas sensors to enhance sensing features towards toxic gases. Findings This work has proved that the synthesis method led to provide different morphologies of nanostructured WO3-based material in turn to improve gas sensing performance along with its sensing mechanism. Originality/value In this work, the authors reviewed challenges and possibilities associated with the nanostructured WO3-based gas sensors to trace toxic gases such as ammonia, H2S and NO2 for future research.

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Section: Introductionmentioning

confidence: 99%

Nanostructured WO₃ based gas sensors: a short review

Sriram

Parne

Vaddadi

et al. 2021

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“…In previous reports, AMT aqueous solutions (with added organic/ inorganic acids or surfactants) were hydrothermally treated to generate WO 3 nanopowders, which were processed into pastes for WO 3 electrode fabrication [38][39][40]. Conversely, ultrasonic spray pyrolysis of AMT aqueous solutions [41], and dip-/spin-coating of aqueous sols comprising AMT and polymer additives [42][43][44][45] were employed to deposit WO 3 thin films on various substrates, including glass, fluorine-doped tin oxide (FTO), and polished alumina substrates. Herein, by establishing a modified sol-gel process in which chemically stable AMT was used as the precursor, the above-mentioned challenge related to enhancing the reproducibility of WO 3 photoanodes is circumvented.…”

Section: Introductionmentioning

confidence: 99%

Sol-gel synthesis of highly reproducible WO3 photoanodes for solar water oxidation

et al. 2020

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Although monoclinic WO 3 is widely studied as a prototypical photoanode material for solar water splitting, limited success, hitherto, in fabricating WO 3 photoanodes that simultaneously demonstrate high efficiency and reproducibility has been realized. The difficulty in controlling both the efficiency and reproducibility is derived from the ever-changing structures/compositions and chemical environments of the precursors, such as peroxytungstic acid and freshly prepared tungstic acid, which render the fabrication processes of the WO 3 photoanodes particularly uncontrollable. Herein, a highly reproducible sol-gel process was developed to establish efficient and translucent WO 3 photoanodes using a chemically stable ammonium metatungstate precursor. Under standard simulated sunlight of air mass 1.5 G, 100 mW cm −2 , the WO 3 photoanode delivered photocurrent densities of ca. 2.05 and 2.25 mA cm −2 at 1.23 V versus the reversible hydrogen electrode (RHE), when tested in 1 mol L −1 H 2 SO 4 and CH 3 SO 3 H, respectively. Hence, the WO 3 photoanodes fabricated herein are one of the WO 3 photoanodes with the highest performance ever reported. The reproducibility of the fabrication scheme was evaluated by testing 50 randomly selected WO 3 samples in 1 mol L −1 H 2 SO 4 , which yielded an average photocurrent density of 1.8 mA cm −2 at 1.23 V RHE with a small standard deviation. Additionally, the effectiveness of the ammonium metatungstate precursor solution was maintained for at least 3 weeks, when compared with the associated upper-limit values of peroxytungstic and tungstic acid-based precursors after 3 d. This study presents a key step to the future development of WO 3 photoanodes for efficient solar water splitting.

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“…Many synthesis routes exist for the fabrication of WO 3 -based gas-sensing elements. Among these, commonly reported pathways include hydrothermal, 21,22 sol-gel, 23,24 sonochemical, 25 physical 12,26 or chemical vapour deposition 27 and electrospinning. 28,29 Typically, the selection of the right synthesis route depends on the desired surface morphology and composition.…”

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confidence: 99%

Optimisation of H‐doped WO₃ synthesis at ambient conditions for potential acetone gas sensing

Tamelarasan,

Lo,

Muthoosamy

et al. 2023

Asia-Pacific J Chem Eng

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Tungsten trioxide (WO3) is a highly desired semiconductor metal oxide (SMO) to detect acetone gas which is present at high levels in the breath of diabetic patients. Current research in the biosensor field is focused on the synthesis of sensing material at room temperature to ease fabrication and reduce energy requirements for operations. In this context, hydrogen doping aids in increasing the baseline conductivity of WO3. Therefore, the current research aimed to synthesise H‐doped WO3 at ambient conditions via an ultrasonication‐assisted hydrogenation route. Besides, the independent effects of other factors on hydrogenation were studied. These include synthesis temperature (room temperature to 80°C) and zinc precursor loading (0.8 to 2.0). By varying the concentrations of WO3 for the synthesis, it was determined that the highest degree of hydrogenation was achieved at 10 mg/ml. This was indicated by a visible colour change to dark blue and the highest conductivity. The findings revealed that hydrogenation is less effective at higher temperatures. The most optimum zinc loading was found to be 1.6 where the maximum attainable conductivity was 116.1 mS/cm. This H‐doped WO3 sample was subsequently subjected to diluted acetone sensing performance. The sample showed a significant reduction in resistance towards diluted acetone of 1000 ppm compared to undoped WO3. Thus, findings from this work offer a potential room temperature‐based synthesis method for acetone detection at low concentration.

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Gas Sensing Characteristics of a WO3 Thin Film Prepared by a Sol-Gel Method

Cited by 5 publications

References 7 publications

Nanostructured WO₃ based gas sensors: a short review

Nanostructured WO₃ based gas sensors: a short review

Sol-gel synthesis of highly reproducible WO3 photoanodes for solar water oxidation

Optimisation of H‐doped WO₃ synthesis at ambient conditions for potential acetone gas sensing

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Gas Sensing Characteristics of a WO3 Thin Film Prepared by a Sol-Gel Method

Cited by 5 publications

References 7 publications

Nanostructured WO3 based gas sensors: a short review

Nanostructured WO3 based gas sensors: a short review

Sol-gel synthesis of highly reproducible WO3 photoanodes for solar water oxidation

Optimisation of H‐doped WO3 synthesis at ambient conditions for potential acetone gas sensing

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Product

Resources

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Nanostructured WO₃ based gas sensors: a short review

Nanostructured WO₃ based gas sensors: a short review

Optimisation of H‐doped WO₃ synthesis at ambient conditions for potential acetone gas sensing