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

Nirmal Kumar; Stanislav Haviar; Petr Zeman

doi:10.3390/nano11123456

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

Nanomaterials ◽

10.3390/nano11123456 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3456

Author(s):

Nirmal Kumar ◽

Stanislav Haviar ◽

Petr Zeman

Keyword(s):

Gas Sensing ◽

Cupric Oxide ◽

Hydrogen Gas ◽

Base Layer ◽

Layer System ◽

Seamless Integration ◽

Hydrogen Sensing ◽

Reactive Sputter Deposition ◽

Copper Tungstate ◽

Higher Sensitivity

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.

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Nanostructured Materials Based on Thin Films and Nanoclusters for Hydrogen Gas Sensing

Proceedings ◽

10.3390/proceedings2020056038 ◽

2021 ◽

Vol 56 (1) ◽

pp. 38

Author(s):

Stanislav Haviar ◽

Nirmal Kumar ◽

Šárka Batková ◽

Jiří Čapek

Keyword(s):

Thin Films ◽

Gas Sensors ◽

Tungsten Trioxide ◽

Gas Sensing ◽

Cupric Oxide ◽

Hydrogen Gas ◽

Oxide Semiconductors ◽

Copper Tungstate ◽

Solid Film ◽

Nanostructured Metal

In this paper, we present two approaches to synthesize nanostructured metal oxide semiconductors in a form of multi-layer thin films later assembled as a conductometric gas-sensors. The first approach produces a combination of thin solid film of tungsten trioxide (WO3) with nanoclusters of cupric oxide (CuO) prepared by a magnetron-based gas aggregation cluster source (GAS). The second method is a two-step reactive magnetron sputtering forming a nanostructured copper tungstate (CuWO4) on-top of a WO3 film. Both methods lead to synthesis of nanosized hetero-junctions. These greatly improve the sensorial response to hydrogen in comparison with a WO3 thin film alone.

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Tuning Stoichiometry and Structure of Pd-WO3−x Thin Films for Hydrogen Gas Sensing by High-Power Impulse Magnetron Sputtering

Materials ◽

10.3390/ma13225101 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5101

Author(s):

Nirmal Kumar ◽

Stanislav Haviar ◽

Jiří Rezek ◽

Pavel Baroch ◽

Petr Zeman

Keyword(s):

Magnetron Sputtering ◽

High Power ◽

Gas Sensing ◽

Pulse Length ◽

Pd Nanoparticles ◽

Hydrogen Gas ◽

Sensory Response ◽

Hydrogen Sensing ◽

Sensing Applications ◽

Deposition Parameters

By tuning the deposition parameters of reactive high-power impulse magnetron sputtering, specifically the pulse length, we were able to prepare WO3−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. WO2.76) 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.

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Superior Hydrogen Sensing Property of Porous NiO/SnO2 Nanofibers Synthesized via Carbonization

Nanomaterials ◽

10.3390/nano9091250 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1250 ◽

Cited By ~ 5

Author(s):

Hongcheng Liu ◽

Feipeng Wang ◽

Kelin Hu ◽

Bin Zhang ◽

Li He ◽

...

Keyword(s):

High Performance ◽

Surface Reaction ◽

Gas Sensing ◽

Hydrogen Gas ◽

Pure Sno2 ◽

Hydrogen Sensing ◽

Adsorption Sites ◽

Electrospinning Method ◽

Sensor Devices ◽

Different Grain Size

In this paper, the porous NiO/SnO2 nanofibers were synthesized via the electrospinning method along with the carbonization process. The characterization results show that the pristine SnO2-based nanofibers can form porous structure with different grain size by carbonization. The hydrogen gas-sensing investigations indicate that the NiO/SnO2 sensor exhibits more prominent sensing properties than those of pure SnO2 sensor devices. Such enhanced performance is mainly attributed to the porous nanostructure, which can provide large active adsorption sites for surface reaction. Moreover, the existence of p-n heterojunctions between NiO and SnO2 also plays a key role in enhancing gas-sensing performances. Finally, the H2 sensing mechanism based on the NiO/SnO2 nanocomposite was proposed for developing high-performance gas sensor devices.

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Significant Enhancement of Hydrogen-Sensing Properties of ZnO Nanofibers through NiO Loading

Nanomaterials ◽

10.3390/nano8110902 ◽

2018 ◽

Vol 8 (11) ◽

pp. 902 ◽

Cited By ~ 18

Author(s):

Jae-Hyoung Lee ◽

Jin-Young Kim ◽

Ali Mirzaei ◽

Hyoun Kim ◽

Sang Kim

Keyword(s):

Metal Oxide ◽

Gas Sensors ◽

High Performance ◽

Gas Sensing ◽

Hydrogen Gas ◽

Electrospinning Technique ◽

Calcination Process ◽

Hydrogen Sensing ◽

Zno Nanofibers ◽

P Type

Metal oxide p-n heterojunction nanofibers (NFs) are among the most promising approaches to enhancing the efficiency of gas sensors. In this paper, we report the preparation of a series of p-NiO-loaded n-ZnO NFs, namely (1−x)ZnO-xNiO (x = 0.03, 0.05, 0.7, 0.1, and 0.15 wt%), for hydrogen gas sensing experiments. Samples were prepared through the electrospinning technique followed by a calcination process. The sensing experiments showed that the sample with 0.05 wt% NiO loading resulted in the highest sensing performance at an optimal sensing temperature of 200 °C. The sensing mechanism is discussed in detail and contributions of the p-n heterojunctions, metallization of ZnO and catalytic effect of NiO on the sensing enhancements of an optimized gas sensor are analyzed. This study demonstrates the possibility of fabricating high-performance H2 sensors through the optimization of p-type metal oxide loading on the surfaces of n-type metal oxides.

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Preparation and Characterization of Pt/WO3 Nano-Film and Its Hydrogen-Sensing Properties

2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems ◽

10.1115/micronano2008-70010 ◽

2008 ◽

Author(s):

Changjun Hou ◽

Jiale Dong ◽

Yan Xu ◽

Danqun Huo ◽

Yike Tang ◽

...

Keyword(s):

Tungsten Trioxide ◽

Gas Sensing ◽

Sol Gel ◽

Hydrogen Gas ◽

Molecular Structures ◽

Oxide Semiconductor ◽

Pt Catalyst ◽

Hydrogen Sensing ◽

Afm Analysis ◽

Type Semiconductor

Tungsten trioxide is an n-type semiconductor, which has been extensively used for the development of metal oxide semiconductor gas sensors. The hydrogen gas sensing performance of platinum (Pt) catalyst activated WO3 thin films were investigated here. All of the Pt/WO3 films membranes are sensitive to hydrogen gas and the sample by sol-gel and DC reactive magnetron sputtering methods. X-ray diffraction results indicate that the tungsten trioxide is cubic crystal, and the AFM analysis shows molecular structures of the samples are tetrahedron. It means the four consecutive quadrilateral forms we observed in the 9nmx9nm molecular structure are scattergram of tungsten-ions and oxide-ions on 106 sides in WO2.9 structure cell, and the lost one oxide-ion resulted in the transition of WO3 to WO2.9. With anneal temperature rising, the membranous poriness decreasing. The higher crystal degree is, the lower gasochromic efficiency is. The change of combining environment and content of O−2 ions in colorized / decolorized state WOx films was observed in XPS analysis of Pt/WO3 film, the peak shape had changed greatly. As a result, the explanation to this phenomenon is available here according to XPS chemical shift of electric potential model theory.

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High Efficiency Crumpled Carbon Nanotube Heaters for Low Drift Hydrogen Sensing

Sensors ◽

10.3390/s19183878 ◽

2019 ◽

Vol 19 (18) ◽

pp. 3878

Author(s):

Jeonhyeong Park ◽

Il Ryu Jang ◽

Kyungtaek Lee ◽

Hoe Joon Kim

Keyword(s):

Carbon Nanotubes ◽

High Efficiency ◽

Gas Sensing ◽

Spray Coating ◽

High Sensitivity ◽

Input Voltage ◽

Hydrogen Gas ◽

Thermal Shrinkage ◽

Hydrogen Sensing ◽

Low Drift

This work presents the fabrication of crumpled carbon nanotubes (C-CNTs) thin film heaters and their application towards high sensitivity and low drift hydrogen gas sensing. Utilizing a spray coating of pristine multi-walled carbon nanotubes (MWCNTs) and thermal shrinkage of polystyrene (PS) substrate, we have fabricated C-CNTs with closely packed junctions. Joule heating of C-CNTs gives higher temperature at a given input voltage compared to as-deposited CNTs. In addition, temperature coefficient of resistance (TCR) is analyzed for accurate temperature control and measurement of the heater. The C-CNT heaters are capable of hydrogen gas sensing while demonstrating higher measurement sensitivities along with lower drift compared to as-deposited CNT devices. In addition, the self-heating of C-CNT heaters help rapid desorption of hydrogen, and thus allowing repetitive and stable sensor operation. Our findings reveal that both CNT morphologies and heating temperatures affect the hydrogen sensing performances.

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Hydrogen gas sensing using aluminum doped ZnO metasurfaces

Nanoscale Advances ◽

10.1039/d0na00289e ◽

2020 ◽

Vol 2 (8) ◽

pp. 3452-3459

Author(s):

Sharmistha Chatterjee ◽

Evgeniy Shkondin ◽

Osamu Takayama ◽

Adam Fisher ◽

Arwa Fraiwan ◽

...

Keyword(s):

Zinc Oxide ◽

Biomedical Applications ◽

Gas Sensing ◽

Hydrogen Gas ◽

Hydrogen Sensing ◽

Aluminum Doped Zinc Oxide ◽

Doped Zno

Hydrogen (H2) sensing is crucial in a wide variety of areas, such as industrial, environmental, energy and biomedical applications. In this work, aluminum-doped zinc oxide (AZO) nanotubes are reported for optical hydrogen sensing.

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Significant Enhancement of Hydrogen-Sensing Properties of ZnO Nanofibers through NiO Loading

10.20944/preprints201808.0354.v1 ◽

2018 ◽

Author(s):

Jae-Hyoung Lee ◽

Jin-Young Kim ◽

Ali Mirzaei ◽

Hyoun Woo Kim ◽

Sang Sub Kim

Keyword(s):

Metal Oxide ◽

Gas Sensors ◽

High Performance ◽

Gas Sensing ◽

Hydrogen Gas ◽

Electrospinning Technique ◽

Calcination Process ◽

Hydrogen Sensing ◽

Zno Nanofibers ◽

P Type

Metal oxide p-n heterojunction nanofibers (NFs) are among the most promising approaches to enhancing the efficiency of gas sensors. In this paper, we report the preparation of a series of p-NiO-loaded n-ZnO NFs, namely (1 − x) ZnO-xNiO (x = 0.03, 0.05, and 0.1 wt%), for hydrogen gas sensing experiments. Samples were prepared through the electrospinning technique followed by a calcination process. The sensing experiments showed that the sample with 0.05 wt% NiO loading resulted in the highest sensing performance at an optimal sensing temperature of 200 °C. The sensing mechanism is discussed in detail and contributions of the p-n heterojunctions, metallization of ZnO and catalytic effect of NiO on the sensing enhancements of an optimized gas sensor are analyzed. This study demonstrates the possibility of fabricating high-performance H2 sensors through the optimization of p-type metal oxide loading on the surfaces of n-type metal oxides.

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Transforming Pt-SnO2 Nanoparticles into Pt-SnO2 Composite Nanoceramics for Room-Temperature Hydrogen-Sensing Applications

Materials ◽

10.3390/ma14092123 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2123

Author(s):

Ming Liu ◽

Caochuang Wang ◽

Pengcheng Li ◽

Liang Cheng ◽

Yongming Hu ◽

...

Keyword(s):

Room Temperature ◽

Gas Sensing ◽

Sintering Temperature ◽

Sno2 Nanoparticles ◽

Hydrogen Sensing ◽

Sensing Applications ◽

Nanostructured Metal Oxides ◽

Low Dimensional ◽

Sensing Characteristics ◽

Nanostructured Metal

Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO2 nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO2 grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2 at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.

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