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11 pages, 8115 KiB

Open AccessArticle

Early Detection of Hydrogen Leakage Using Fiber Optic Hydrogen Sensor Based on WO₃-PdPt-Pt Nanocomposite Films

by Jixiang Dai, Zhangning Chen, Rundong Yang, Zhouyang Wu, Zhengan Tang, Wenbin Hu, Cheng Cheng, Xuewen Wang and Minghong Yang

Nanomaterials 2025, 15(11), 836; https://doi.org/10.3390/nano15110836 - 30 May 2025

Viewed by 467

Abstract

Quickly detecting hydrogen leakage is crucial to provide early warning for taking emergency measures to avoid personnel casualties and explosion accidents in hydrogen energy fields. Here, a compact optical fiber hydrogen sensing system with high sensitivity and quick response rate is proposed in [...] Read more.

Quickly detecting hydrogen leakage is crucial to provide early warning for taking emergency measures to avoid personnel casualties and explosion accidents in hydrogen energy fields. Here, a compact optical fiber hydrogen sensing system with high sensitivity and quick response rate is proposed in this work. A laser diode (LD) and two photodetectors (PD) are employed as light source and optical signal transformation devices, respectively. This sensing system employs single-mode optical fiber deposited with WO₃-PdPt-Pt nanocomposite film system as sensing element. Under irrigating power of 6 mW, the sensing probe exhibits an ultra-fast response to hydrogen concentrations of 4000 ppm and 10,000 ppm, with response times of 0.44 s and 0.34 s, respectively. In addition, detection limit of 3 ppm can be achieved by using this sensing system. The sensor also shows good repeatability during hydrogen exposure of 3~10,000 ppm, demonstrating its great potential application for hydrogen leakage in hydrogen energy facilities. Full article

(This article belongs to the Special Issue Nanomaterials and 2D Materials Based on Semiconductors and Metals: Second Edition)

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16 pages, 5683 KiB

Open AccessArticle

Three-Layer PdO/CuWO₄/CuO System for Hydrogen Gas Sensing with Reduced Humidity Interference

by Nirmal Kumar, Stanislav Haviar and Petr Zeman

Nanomaterials 2021, 11(12), 3456; https://doi.org/10.3390/nano11123456 - 20 Dec 2021

Cited by 10 | Viewed by 3326

Abstract

The growing hydrogen industry is stimulating an ongoing search for new materials not only for hydrogen production or storage but also for hydrogen sensing. These materials have to be sensitive to hydrogen, but additionally, their synthesis should be compatible with the microcircuit industry [...] Read more.

The growing hydrogen industry is stimulating an ongoing search for new materials not only for hydrogen production or storage but also for hydrogen sensing. These materials have to be sensitive to hydrogen, but additionally, their synthesis should be compatible with the microcircuit industry to enable seamless integration into various devices. In addition, the interference of air humidity remains an issue for hydrogen sensing materials. We approach these challenges using conventional reactive sputter deposition. Using three consequential processes, we synthesized multilayer structures. A basic two-layer system composed of a base layer of cupric oxide (CuO) overlayered with a nanostructured copper tungstate (CuWO₄) exhibits higher sensitivity than individual materials. This is explained by the formation of microscopic heterojunctions. The addition of a third layer of palladium oxide (PdO) in forms of thin film and particles resulted in a reduction in humidity interference. As a result, a sensing three-layer system working at 150 °C with an equalized response in dry/humid air was developed. Full article

(This article belongs to the Special Issue Nanostructured Materials for Gas Sensor Applications)

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1 pages, 174 KiB

Open AccessAbstract

Tungsten Oxide Based Hydrogen Gas Sensor Prepared by Advanced Magnetron Sputtering

by Nirmal Kumar, Stanislav Haviar, Jiří Rezek, Jiří Čapek and Pavel Baroch

Eng. Proc. 2021, 6(1), 5; https://doi.org/10.3390/I3S2021Dresden-10154 - 18 May 2021

Viewed by 1020

Abstract

In this study, we demonstrate the advantages of two advanced sputtering techniques for the preparation of a thin-film conductometric gas sensor. We combined tungsten oxide (WO₃) thin films with other materials to achieve enhanced sensorial behavior towards hydrogen. Thin films of [...] Read more.

In this study, we demonstrate the advantages of two advanced sputtering techniques for the preparation of a thin-film conductometric gas sensor. We combined tungsten oxide (WO₃) thin films with other materials to achieve enhanced sensorial behavior towards hydrogen. Thin films of WO₃ were prepared using the DC and HiPIMS technique, which allowed us to tune the phase composition and crystallinity of the oxide by changing the deposition parameters. The second material was then added on-top of these films. We used the copper tungstate CuWO₄ in the form of nano-islands deposited by reactive rf sputtering and Pd particles formed during conventional dc sputtering. The specimens were tested for their response to a time-varied hydrogen concentration in synthetic air at various temperatures. The sensitivity and response time were evaluated. The performance of the individual films is presented as well as the details of the synthesis. Advanced magnetron techniques (such as HiPIMS) allowed us to tune the property of the film to improve its sensorial behavior. The method is compatible with the silicon electronics industry and consists of a few steps that do not require any wet technique, and the films can be used in an as-deposited state. Therefore, sensorial nanostructured materials prepared using magnetron sputtering are very suitable for use in miniaturized electronic devices. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

9 pages, 2415 KiB

Open AccessArticle

Fiber Optical Hydrogen Sensor Based on WO₃-Pd₂Pt-Pt Nanocomposite Films

by Jixiang Dai, Yi Li, Hongbo Ruan, Zhuang Ye, Nianyao Chai, Xuewen Wang, Shuchang Qiu, Wei Bai and Minghong Yang

Nanomaterials 2021, 11(1), 128; https://doi.org/10.3390/nano11010128 - 8 Jan 2021

Cited by 29 | Viewed by 3558

Abstract

In this paper, WO₃-Pd₂Pt-Pt nanocomposite films were deposited on a single mode fiber as the hydrogen sensing material, which changes its reflectivity under different hydrogen concentration. The reflectivity variation was probed and converted to an electric signal by a [...] Read more.

In this paper, WO₃-Pd₂Pt-Pt nanocomposite films were deposited on a single mode fiber as the hydrogen sensing material, which changes its reflectivity under different hydrogen concentration. The reflectivity variation was probed and converted to an electric signal by a pair of balanced InGaAs photoelectric detectors. In addition, the performance of the WO₃-Pd₂Pt-Pt composite film was investigated under different optical powers, and the irrigating power was optimized at 5 mW. With the irrigation of this optical power, the hydrogen sensitive film exhibits quick response toward 100 ppm hydrogen in air atmosphere at a room temperature of 25 °C. The experimental results demonstrate a high resolution at 5 parts per million (ppm) within a wide range from 100 to 5000 ppm in air. This simple and compact sensing system can detect hydrogen concentrations far below the explosion limit and provide early alert for hydrogen leakage, showing great potential in hydrogen-related applications. Full article

(This article belongs to the Special Issue Nanomaterials and Nanotechnology in Experimental Photonics)

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12 pages, 3374 KiB

Open AccessArticle

Tuning Stoichiometry and Structure of Pd-WO_3−x Thin Films for Hydrogen Gas Sensing by High-Power Impulse Magnetron Sputtering

by Nirmal Kumar, Stanislav Haviar, Jiří Rezek, Pavel Baroch and Petr Zeman

Materials 2020, 13(22), 5101; https://doi.org/10.3390/ma13225101 - 12 Nov 2020

Cited by 5 | Viewed by 2265

Abstract

By tuning the deposition parameters of reactive high-power impulse magnetron sputtering, specifically the pulse length, we were able to prepare WO_3−x films with various stoichiometry and structure. Subsequently, the films were annealed in air at moderate temperature (350 °C). We demonstrate [...] Read more.

By tuning the deposition parameters of reactive high-power impulse magnetron sputtering, specifically the pulse length, we were able to prepare WO_3−x films with various stoichiometry and structure. Subsequently, the films were annealed in air at moderate temperature (350 °C). We demonstrate that the stoichiometry of the as-deposited films influences considerably the type of crystalline phase formed in the annealed films. The appropriate sub-stoichiometry of the films (approx. WO_2.76) enabled crystallization of the monoclinic phase during the annealing. This phase is favorable for hydrogen sensing applications. To characterize the sensory behavior of the films, the tungsten oxide films were decorated by Pd nanoparticles before annealing and were assembled as a conductometric gas sensor. The sensory response of the films that crystallized in the monoclinic structure was proven to be superior to that of the films containing other phases. Full article

(This article belongs to the Special Issue Innovative Plasma-Based Deposition Techniques for the Production of Functional Materials)

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10 pages, 4191 KiB

Open AccessArticle

Surface Acoustic Wave Hydrogen Sensors Based on Nanostructured Pd/WO₃ Bilayers

by Dana Miu, Ruxandra Birjega and Cristian Viespe

Sensors 2018, 18(11), 3636; https://doi.org/10.3390/s18113636 - 26 Oct 2018

Cited by 25 | Viewed by 4148

Abstract

The effect of nanostructure of PLD (Pulsed Laser Deposition)-deposited Pd/WO₃ sensing films on room temperature (RT) hydrogen sensing properties of SAW (Surface Acoustic Wave) sensors was studied. WO₃ thin films with different morphologies and crystalline structures were obtained for different substrate [...] Read more.

The effect of nanostructure of PLD (Pulsed Laser Deposition)-deposited Pd/WO₃ sensing films on room temperature (RT) hydrogen sensing properties of SAW (Surface Acoustic Wave) sensors was studied. WO₃ thin films with different morphologies and crystalline structures were obtained for different substrate temperatures and oxygen deposition pressures. Nanoporous films are obtained at high deposition pressures regardless of the substrate temperature. At lower pressures, high temperatures lead to WO₃ c-axis nanocolumnar growth, which promotes the diffusion of hydrogen but only once H₂ has been dissociated in the nanoporous Pd layer. XRD (X-ray Diffraction) analysis indicates texturing of the WO₃ layer not only in the case of columnar growth but for other deposition conditions as well. However, it is only the predominantly c-axis growth that influences film sensing properties. Bilayers consisting of nanoporous Pd layers deposited on top of such WO₃ layers lead to good sensing results at RT. RT sensitivities of 0.12–0.13 Hz/ppm to hydrogen are attained for nanoporous bilayer Pd/WO₃ films and of 0.1 Hz/ppm for bilayer films with a nanocolumnar WO₃ structure. SAW sensors based on such layers compare favorably with WO₃-based hydrogen detectors, which use other sensing methods, and with SAW sensors with dense Pd/WO₃ bilayers. Full article

(This article belongs to the Collection Gas Sensors)

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14 pages, 3541 KiB

Open AccessArticle

Effect of the Functionalization of Porous Silicon/WO₃ Nanorods with Pd Nanoparticles and Their Enhanced NO₂-Sensing Performance at Room Temperature

by Xiaoyong Qiang, Ming Hu, Boshuo Zhao, Yue Qin, Ran Yang, Liwei Zhou and Yuxiang Qin

Materials 2018, 11(5), 764; https://doi.org/10.3390/ma11050764 - 10 May 2018

Cited by 18 | Viewed by 4326

Abstract

The decoration of noble metal nanoparticles (NPs) on the surface of metal oxide semiconductors to enhance material characteristics and gas-sensing performance has recently attracted increasing attention from researchers worldwide. Here, we have synthesized porous silicon (PS)/WO₃ nanorods (NRs) functionalized with Pd NPs [...] Read more.

The decoration of noble metal nanoparticles (NPs) on the surface of metal oxide semiconductors to enhance material characteristics and gas-sensing performance has recently attracted increasing attention from researchers worldwide. Here, we have synthesized porous silicon (PS)/WO₃ nanorods (NRs) functionalized with Pd NPs to enhance NO₂ gas-sensing performance. PS was first prepared using electrochemical methods and worked as a substrate. WO₃ NRs were synthesized by thermally oxidizing W film on the PS substrate. Pd NPs were decorated on the surface of WO₃ NRs via in-situ reduction of the Pd complex solution by using Pluronic P123 as the reducing agent. The gas-sensing characteristics were tested at different gas concentrations and different temperatures ranging from room temperature to 200 °C. Results revealed that, compared with bare PS/WO₃ NRs and Si/WO₃ NRs functionalized with Pd NPs, the Pd-decorated PS/WO₃ NRs exhibited higher and quicker responses to NO₂, with a detection concentration as low as 0.25 ppm and a maximum response at room temperature. The gas-sensing mechanism was also investigated and is discussed in detail. The high surface area to volume ratio of PS and the reaction-absorption mechanism can be explained the enhanced sensing performance. Full article

(This article belongs to the Special Issue Metal Oxide Nanostructure for Solid-State Electronics and Sensors)

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10 pages, 2164 KiB

Open AccessArticle

A New Hydrogen Sensor Based on SNS Fiber Interferometer with Pd/WO₃ Coating

by Jinxin Shao, Wenge Xie, Xi Song and Yanan Zhang

Sensors 2017, 17(9), 2144; https://doi.org/10.3390/s17092144 - 18 Sep 2017

Cited by 18 | Viewed by 6259

Abstract

This paper presents a new hydrogen sensor based on a single mode–no core–single mode (SNS) fiber interferometer structure. The surface of the no core fiber (NCF) was coated by Pd/WO₃ film to detect the variation of hydrogen concentration. If the hydrogen concentration [...] Read more.

This paper presents a new hydrogen sensor based on a single mode–no core–single mode (SNS) fiber interferometer structure. The surface of the no core fiber (NCF) was coated by Pd/WO₃ film to detect the variation of hydrogen concentration. If the hydrogen concentration changes, the refractive index of the Pd/WO₃ film as well as the boundary condition for light propagating in the NCF will all be changed, which will then cause a shift into the resonant wavelength of interferometer. Therefore, the hydrogen concentration can be deduced by measuring the shift of the resonant wavelength. Experimental results demonstrated that this proposed sensor had a high detection sensitivity of 1.26857 nm/%, with good linearity and high accuracy (maximum 0.0055% hydrogen volume error). Besides, it also possessed the advantages of simple structure, low cost, good stability, and repeatability. Full article

(This article belongs to the Special Issue Novel Approaches to Biosensing with Nanoparticles)

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5 pages, 1370 KiB

Open AccessProceeding Paper

Oxyhydrogen and Hydrogen Detection by Gasochromic Coloration of Highly Porous Tungsten Oxide with Fractal-Like Pd Nanoparticles

by Mehdi Ranjbar and Giorgio Sberveglieri

Proceedings 2017, 1(4), 487; https://doi.org/10.3390/proceedings1040487 - 28 Aug 2017

Cited by 2 | Viewed by 1994

Abstract

WO₃ thin films were deposited by pulsed laser deposition (PLD) on glass substrates at 100 mTorr oxygen pressure. Monodispersed palladium nanoparticles (50 nm) were synthesized by hydrogen reduction of PdCl₂ drop-casted on the surface of the films. For oxyhydrogen detection, first [...] Read more.

WO₃ thin films were deposited by pulsed laser deposition (PLD) on glass substrates at 100 mTorr oxygen pressure. Monodispersed palladium nanoparticles (50 nm) were synthesized by hydrogen reduction of PdCl₂ drop-casted on the surface of the films. For oxyhydrogen detection, first a saturated coloration by 10%H₂/Ar was prepared. Then different oxygen flow with certain O₂:H₂ ratios were exposed to the colored samples. Depending on this ratio, the optical density of samples was observed to drop into certain new values until vanishes for a ratio about 20. A desirable fast coloration with linear dependency on hydrogen concentration was also observed. Full article

(This article belongs to the Proceedings of Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017)

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