A morphological control of tungsten oxide nanowires by thermal evaporation method for sub-ppm NO2 gas sensor application

Hieu, Nguyen Van; Vuong, Hoang Van; Duy, Nguyễn Văn; Hòa, Nguyễn Đức

doi:10.1016/j.snb.2012.05.069

Cited by 60 publications

(19 citation statements)

References 41 publications

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“…GO acts as a catalytic promoter favoring surface reactions between ammonia gas and the adsorbed oxygen species on the sensor surface. Our results exhibited higher response toward ammonia gas sensing (see Table 1) in a relatively shorter time when compared with some various structural WO 3 catalysts, GO.WO 3 composites and when WO 3 forms heterojunction with other oxides (Wang et al, 2006; Hieu et al, 2011, 2012; Toan et al, 2017; Behera and Chandra, 2018; Prabhu et al, 2018).…”

Section: Resultsmentioning

confidence: 61%

Synthesis of Graphene Oxide Interspersed in Hexagonal WO3 Nanorods for High-Efficiency Visible-Light Driven Photocatalysis and NH3 Gas Sensing

et al. 2019

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WO3 nanorods and GO (at 1 wt% loading) doped WO3 were synthesized using a template free deposition-hydrothermal route and thoroughly characterized by various techniques including XRD, FTIR, Raman, TEM-SAED, PL, UV-Vis, XPS, and N2 adsorption. The nano-materials performance was investigated toward photocatalytic degradation of methylene blue dye (20 ppm) under visible light illumination (160 W, λ> 420) and gas sensing ability for ammonia gas (10–100 ppm) at 200°C. HRTEM investigation of the 1%GO.WO3 composite revealed WO3 nanorods of a major d-spacing value of 0.16 nm indexed to the crystal plane (221). That relevant plane was absent in pure WO3 establishing the intercalation with GO. The MB degradation activity was considerably enhanced over the 1%GO.WO3 catalyst with a rate constant of 0.0154 min−1 exceeding that of WO3 by 15 times. The reaction mechanism was justified dependent on electrons, holes and •OH reactive species as determined via scavenger examination tests and characterization techniques. The drop in both band gap (2.49 eV) and PL intensity was the main reason responsible for enhancing the photo-degradation activity of the 1%GO.WO3 catalyst. The later catalyst initiated the two electron O2 reduction forming H2O2, that contributed in the photoactivity improvement via forming •OH moieties. The hexagonal structure of 1%GO.WO3 showed a better gas sensing performance for ammonia gas at 100 ppm (Ra-Rg/Rg = 17.6) exceeding that of pure WO3 nanorods (1.27). The superiority of the gas-sensing property of the 1%GO.WO3 catalyst was mainly ascribed to the high dispersity of GO onto WO3 surfaces by which different carbon species served as mediators to hinder the recombination rate of photo-generated electron-hole pairs and therefore facilitated the electron transition. The dominancy of the lattice plane (221) in 1%GO.WO3 formed between GO and WO3 improved the electron transport in the gas-sensing process.

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Section: Resultsmentioning

confidence: 61%

Synthesis of Graphene Oxide Interspersed in Hexagonal WO3 Nanorods for High-Efficiency Visible-Light Driven Photocatalysis and NH3 Gas Sensing

et al. 2019

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“…[15c] Coupled with atomic force microscopy (AFM; SI: Figure S3), it was determined that the thickness of C 3 N 4 ‐NS was about 5.65 nm, corresponding to less than 17 layers, considering the theoretical thickness of a single layer of C 3 N 4 (∼0.34 nm) . The Raman spectrum for the 3DB WO 3 ‐NA/C 3 N 4 ‐NS heterojunction (SI: Figure S4) shows characteristic bands at 127, 262, 318, 707, and 801 cm −1 , corresponding to the bending and stretching vibration modes of monoclinic WO 3 . Two additional bands at 1363 and 1609 cm −1 are observed; they are assigned to the D and G bands of graphitic C 3 N 4 , respectively .…”

Section: Methodsmentioning

confidence: 99%

Branched WO₃ Nanosheet Array with Layered C₃N₄ Heterojunctions and CoO_x Nanoparticles as a Flexible Photoanode for Efficient Photoelectrochemical Water Oxidation

et al. 2014

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A hybrid WO3 /C3 N4 /CoOx system exhibits excellent photoelectrochemical activity for water oxidation. The system comprises a novel three-dimensionally branched WO3 nanosheet array coated with a layer of C3 N4 heterojunctions that are further decorated with CoOx nanoparticles. The photoelectrochemical activity arises from the effective light harvesting due to the 3D structure and "window effect," the excellent charge separation and transport in the heterojunction, and the fast interfacial charge collection and surface reactions due to the large surface area.

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“…Since E. Comini, et al 6 demonstrated highly sensitive ethanol sensor using SnO 2 nanobelts, 1D nanomaterial based sensors have been widely developed to detect various kinds of gases such as CO, H 2 , H 2 S, NO 2 , O 3 , etc 7 8 9 10 11 . Moreover, they have shown high sensitivity for the detection of sub-ppm or ppb level concentrations, depending on the types of gases 11 12 13 14 15 . In order to realize highly integrated sensors with 1D nanomaterials, they have to be assembled and integrated on functional electronic chips in a controlled manner.…”

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confidence: 99%

Fabrication of heterogeneous nanomaterial array by programmable heating and chemical supply within microfluidic platform towards multiplexed gas sensing application

Yang

Kang

Kim

et al. 2015

Sci Rep

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A facile top-down/bottom-up hybrid nanofabrication process based on programmable temperature control and parallel chemical supply within microfluidic platform has been developed for the all liquid-phase synthesis of heterogeneous nanomaterial arrays. The synthesized materials and locations can be controlled by local heating with integrated microheaters and guided liquid chemical flow within microfluidic platform. As proofs-of-concept, we have demonstrated the synthesis of two types of nanomaterial arrays: (i) parallel array of TiO2 nanotubes, CuO nanospikes and ZnO nanowires, and (ii) parallel array of ZnO nanowire/CuO nanospike hybrid nanostructures, CuO nanospikes and ZnO nanowires. The laminar flow with negligible ionic diffusion between different precursor solutions as well as localized heating was verified by numerical calculation and experimental result of nanomaterial array synthesis. The devices made of heterogeneous nanomaterial array were utilized as a multiplexed sensor for toxic gases such as NO2 and CO. This method would be very useful for the facile fabrication of functional nanodevices based on highly integrated arrays of heterogeneous nanomaterials.

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A morphological control of tungsten oxide nanowires by thermal evaporation method for sub-ppm NO2 gas sensor application

Cited by 60 publications

References 41 publications

Synthesis of Graphene Oxide Interspersed in Hexagonal WO3 Nanorods for High-Efficiency Visible-Light Driven Photocatalysis and NH3 Gas Sensing

Synthesis of Graphene Oxide Interspersed in Hexagonal WO3 Nanorods for High-Efficiency Visible-Light Driven Photocatalysis and NH3 Gas Sensing

Branched WO₃ Nanosheet Array with Layered C₃N₄ Heterojunctions and CoO_x Nanoparticles as a Flexible Photoanode for Efficient Photoelectrochemical Water Oxidation

Fabrication of heterogeneous nanomaterial array by programmable heating and chemical supply within microfluidic platform towards multiplexed gas sensing application

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A morphological control of tungsten oxide nanowires by thermal evaporation method for sub-ppm NO2 gas sensor application

Cited by 60 publications

References 41 publications

Synthesis of Graphene Oxide Interspersed in Hexagonal WO3 Nanorods for High-Efficiency Visible-Light Driven Photocatalysis and NH3 Gas Sensing

Synthesis of Graphene Oxide Interspersed in Hexagonal WO3 Nanorods for High-Efficiency Visible-Light Driven Photocatalysis and NH3 Gas Sensing

Branched WO3 Nanosheet Array with Layered C3N4 Heterojunctions and CoOx Nanoparticles as a Flexible Photoanode for Efficient Photoelectrochemical Water Oxidation

Fabrication of heterogeneous nanomaterial array by programmable heating and chemical supply within microfluidic platform towards multiplexed gas sensing application

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Branched WO₃ Nanosheet Array with Layered C₃N₄ Heterojunctions and CoO_x Nanoparticles as a Flexible Photoanode for Efficient Photoelectrochemical Water Oxidation