Anodized nanoporous WO<sub>3</sub>Schottky contact structures for hydrogen and ethanol sensing

Kadir, Rosmalini Ab; Zhang, Wei; Wang, Yichao; Ou, Jian Zhen; Włodarski, W.; O’Mullane, Anthony P.; Bryant, Gary; Taylor, Matthew; Kalantar‐zadeh, Kourosh

doi:10.1039/c4ta06286h

Cited by 71 publications

(26 citation statements)

References 68 publications

(84 reference statements)

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“…As shown in Figure 6b, the corresponding band gaps of g-C 3 N 4 and WO 3 are estimated to be 2.62 and 3.17 eV. The band gap of WO 3 in this work is larger than that from previous reports, 10,12,29−31 which may be caused by the ultrathin diameter of nanorods. After the introduction of oxygen vacancies, the band gap of WO 3– x nanorods remains as 3.17 eV.…”

Section: Resultsmentioning

confidence: 46%

Enhanced Photocatalytic CO₂ Reduction in Defect-Engineered Z-Scheme WO_3–x/g-C₃N₄ Heterostructures

et al. 2019

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Oxygen vacancy-modified WO3–x nanorods composited with g-C3N4 have been synthesized via the chemisorption method. The crystalline structure, morphology, composition, band structure, and charge separation mechanism for WO3–x/g-C3N4 heterostructures are studied in detail. The g-C3N4 nanosheets are attached on the surface of WO3–x nanorods. The Z-scheme separation is confirmed by the analysis of generated hydroxyl radicals. The electrons in the lowest unoccupied molecular orbital of g-C3N4 and the holes in the valence band of WO3 can participate in the photocatalytic reaction to reduce CO2 into CO. New energy levels of oxygen vacancies are formed in the band gap of WO3, further extending the visible-light response, separating the charge carriers in Z-scheme and prolonging the lifetime of electrons. Therefore, the WO3–x/g-C3N4 heterostructures exhibit much higher photocatalytic activity than the pristine g-C3N4.

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Section: Resultsmentioning

confidence: 46%

Enhanced Photocatalytic CO₂ Reduction in Defect-Engineered Z-Scheme WO_3–x/g-C₃N₄ Heterostructures

et al. 2019

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“…Hence, a lot of research has been devoted toward their study in the last two decades, in order to explore their response, selectivity, stabiliy, new fabrication techniques, and sensing mechanism etc. A number of metal oxide systems have been studied for the same and the general mechanism developed has been successfully able to explain for most of the oxide systems . Thus, there have been efforts to understand the underlying physics of metal oxide semiconductors through their interaction with various gases using specific surface techniques.…”

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confidence: 99%

Analysis of Unusual and Instantaneous Overshoot of Response Transients in Gas Sensors

Suresh

Urs

Vasudevan

et al. 2019

Physica Rapid Research Ltrs

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Hydrogen is known to diffuse through particular planes of ZnO crystals. However, in spite of being an established gas sensor material, such diffusion related effects have not been reported in gas sensor properties of ZnO in the literature to the best of our knowledge. Here, we report a prominent overshoot observed in the response transients of single crystalline large ZnO microrods sensor upon exposure to hydrogen gas. This overshoot intensity and time has been found to vary systematically with the temperature as well as gas concentration. In spite of larger size of rods (diameter ≈1–3 µm), it shows a very high response of nearly 950% for 1000 ppm hydrogen at 300 °C. The observed overshoot is very prominent at temperatures below 300 °C. This unusual behavior has been attributed to the bulk diffusion of atomic hydrogen into the subsurface of ZnO microrods. The coefficient of diffusivity, estimated from the time of overshoot, is found to be typically 10−15 m2 s−1, at 250 °C, and its thermal activation energy has been found to be 0.22 eV. The lack of grain boundaries within the microrods and surface gradient driven diffused hydrogen species have been proposed as the origin of unusual overshoot profiles.

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“…chemical wet etch, anodization, hydrothermal and solvothermal technique) and dry chemistry methods (e.g. spray pyrolysis, thermal evaporation and plasma assisted technique) [20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Efficient plasma-assisted approach in nanostructure fabrication of tungsten

Fan

Sun

et al. 2016

Materials & Design

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Anodized nanoporous WO₃Schottky contact structures for hydrogen and ethanol sensing

Abstract: Reversibility of the gas sensor made of a 500 nm thick WO3 nanoporous film upon exposure to hydrogen gas at 200 °C.

Cited by 71 publications

References 68 publications

Enhanced Photocatalytic CO₂ Reduction in Defect-Engineered Z-Scheme WO_3–x/g-C₃N₄ Heterostructures

Enhanced Photocatalytic CO₂ Reduction in Defect-Engineered Z-Scheme WO_3–x/g-C₃N₄ Heterostructures

Analysis of Unusual and Instantaneous Overshoot of Response Transients in Gas Sensors

Efficient plasma-assisted approach in nanostructure fabrication of tungsten

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Anodized nanoporous WO3Schottky contact structures for hydrogen and ethanol sensing

Abstract: Reversibility of the gas sensor made of a 500 nm thick WO3 nanoporous film upon exposure to hydrogen gas at 200 °C.

Cited by 71 publications

References 68 publications

Enhanced Photocatalytic CO2 Reduction in Defect-Engineered Z-Scheme WO3–x/g-C3N4 Heterostructures

Enhanced Photocatalytic CO2 Reduction in Defect-Engineered Z-Scheme WO3–x/g-C3N4 Heterostructures

Analysis of Unusual and Instantaneous Overshoot of Response Transients in Gas Sensors

Efficient plasma-assisted approach in nanostructure fabrication of tungsten

Contact Info

Product

Resources

About

Anodized nanoporous WO₃Schottky contact structures for hydrogen and ethanol sensing

Enhanced Photocatalytic CO₂ Reduction in Defect-Engineered Z-Scheme WO_3–x/g-C₃N₄ Heterostructures

Enhanced Photocatalytic CO₂ Reduction in Defect-Engineered Z-Scheme WO_3–x/g-C₃N₄ Heterostructures