Synthesis of WO3 nanoflakes by hydrothermal route and its gas sensing application

• Published in: Sensors and actuators. A. Physical. Vol. 304; p. 111877
• Main Authors: Kolhe, Pankaj S., Mutadak, Pallavi, Maiti, Namita, Sonawane, Kishor M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-04-2020; Elsevier BV
• Subjects: Ammonia; Chemical properties; Diffraction; Electron microscopy; Gas sensors; Hydrogen sulfide; Hydrothermal method; Inorganic materials; Morphology; NH3gas sensing; Photoelectrons; Power consumption; Pre-seeding WO3; Raman spectroscopy; Scanning electron microscopy; Sensors; Spectrum analysis; Spray pyrolysis; Substrates; Thin films; Transmission electron microscopy; Tungsten oxides; WO3nanoflakes; X ray photoelectron spectroscopy; Pre-seeding WO3; Hydrothermal method; WO3nanoflakes; NH3gas sensing
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2020.111877

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•WO3 seed layer deposited by spray pyrolysis for growth of WO3 nanoflaked thin film using hydrothermal method.•Flakes morphology provides large surface area and active sites for improving gas sensing.•High selectivity towards NH3 gas detection.•Higher sensitivity with fast response and recovery time at comparatively lower temperature (150 °C) is obtained.
The controlled morphology and size of inorganic materials have attracted intense interest, as these parameters play an important role in determining sensing properties. Herein, WO3 thin film is hydrothermally grown on FTO substrate at 175 ℃ with the assistance of seed layer deposited by spray pyrolysis technique. The WO3 thin film was characterized by X-ray Diffraction (XRD), micro-Raman spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and UV–vis Spectroscopy for determination of physico-chemical properties. Moreover, X-ray Photoelectron Spectroscopy (XPS) analysis is carried out to understand chemical states and boding. Systematic gas sensing studies were performed for NH3, H2S and CO gases under static condition. The sensing study reveals, WO3 nanoflake exhibits a superior sensor response to NH3 gas. Moreover, it exhibits higher sensitivity to NH3. Gas sensing properties indicate WO3 nanoflakes holds promise to become a potential candidate for NH3 gas detection at the expense of lower power consumption.