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

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1250 ◽  
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.

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

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 902 ◽  
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.

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

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.

scholarly journals Enhanced Hydrogen Detection in ppb-Level by Electrospun SnO2-Loaded ZnO Nanofibers

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 726 ◽  
Author(s):  
Jae-Hyoung Lee ◽  
Jin-Young Kim ◽  
Jae-Hun Kim ◽  
Sang Kim
Keyword(s):  
Gas Sensor ◽  
High Performance ◽  
Hydrogen Gas ◽  
Hydrogen Sensors ◽  
Excellent Performance ◽  
Electrospinning Technique ◽  
Hydrogen Sensing ◽  
Working Temperature ◽  
Highly Sensitive ◽  
Zno Nanofibers

High-performance hydrogen sensors are important in many industries to effectively address safety concerns related to the production, delivering, storage and use of H2 gas. Herein, we present a highly sensitive hydrogen gas sensor based on SnO2-loaded ZnO nanofibers (NFs). The xSnO2-loaded (x = 0.05, 0.1 and 0.15) ZnO NFs were fabricated using an electrospinning technique followed by calcination at high temperature. Microscopic analyses demonstrated the formation of NFs with expected morphology and chemical composition. Hydrogen sensing studies were performed at various temperatures and the optimal working temperature was selected as 300 °C. The optimal gas sensor (0.1 SnO2 loaded ZnO NFs) not only showed a high response to 50 ppb hydrogen gas, but also showed an excellent selectivity to hydrogen gas. The excellent performance of the gas sensor to hydrogen gas was mainly related to the formation of SnO2-ZnO heterojunctions and the metallization effect of ZnO.

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

Materials ◽  
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.

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

Nanomaterials ◽  
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.

scholarly journals A Separated Receptor/Transducer Scheme as Strategy to Enhance the Gas Sensing Performance Using Hematite–Carbon Nanotube Composite

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3915 ◽  
Author(s):  
Nguyen Minh Hieu ◽  
Cao Van Phuoc ◽  
Truong Thi Hien ◽  
Nguyen Duc Chinh ◽  
Nguyen Duc Quang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Composite Structures ◽  
High Performance ◽  
Gas Sensing ◽  
Arc Discharge ◽  
Adsorption Sites ◽  
Thin Carbon ◽  
Sensor Structure ◽  
Ammonia Detection ◽  
Sensing Performance

Nanocomposite structures, where the Fe, Fe2O3, or Ni2O3 nanoparticles with thin carbon layers are distributed among a single-wall carbon nanotube (SWCNT) network, are architectured using the co-arc discharge method. A synergistic effect between the nanoparticles and SWCNT is achieved with the composite structures, leading to the enhanced sensing response in ammonia detection. Thorough studies about the correlation between the electric properties and sensing performance confirm the independent operation of the receptor and transducer in the sensor structure by nanoparticles and SWCNT, respectively. Nanoparticles with a large specific surface area provide adsorption sites for the NH3 gas molecules, whereas hole carriers are supplied by the SWCNT to complete the chemisorption process. A new chemo-resistive sensor concept and its operating mechanism is proposed in our work. Furthermore, the separated receptor and transducer sensor scheme allows us more freedom in the design of sensor materials and structures, thereby enabling the design of high-performance gas sensors.

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

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.

scholarly journals High Efficiency Crumpled Carbon Nanotube Heaters for Low Drift Hydrogen Sensing

Sensors ◽  
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.

scholarly journals Polymer-Templated Durable and Hydrophobic Nanostructures for Hydrogen Gas Sensing Applications

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4470
Author(s):  
Mohammad Kamal Hossain ◽  
Qasem Ahmed Drmosh
Keyword(s):  
Contact Angle ◽  
Surface Area ◽  
Gas Adsorption ◽  
Sessile Drop ◽  
Gas Sensing ◽  
Hydrogen Gas ◽  
Adsorption Sites ◽  
Wetting Contact Angle ◽  
Sensing Applications ◽  
Surface Nanostructures

A simple and hands-on one-step process has been implemented to fabricate polymer-templated hydrophobic nanostructures as hydrogen gas sensing platforms. Topographic measurements have confirmed irregular hills and dips of various dimensions that are responsible for creating air bubble pockets that satisfy the Cassie–Baxter state of hydrophobicity. High-resolution field-emission scanning electron microscopy (FESEM) has revealed double-layer structures consisting of fine microscopic flower-like structures of nanoscale petals on the top of base nanostructures. Wetting contact angle (WCA) measurements further revealed the contact angle to be ~142.0° ± 10.0°. Such hydrophobic nanostructures were expected to provide a platform for gas-sensing materials of a higher surface area. From this direction, a very thin layer of palladium, ca. 100 nm of thickness, was sputtered. Thereafter, further topographic and WCA measurements were carried out. FESEM micrographs revealed that microscopic flower-like structures of nanoscale petals remained intact. A sessile drop test reconfirmed a WCA of as high as ~130.0° ± 10.0°. Due to the inherent features of hydrophobic nanostructures, a wider surface area was expected that can be useful for higher target gas adsorption sites. In this context, a customized sensing facility was set up, and H2 gas sensing performance was carried out. The surface nanostructures were found to be very stable and durable over the course of a year and beyond. A polymer-based hydrophobic gas-sensing platform as investigated in this study will play a dual role in hydrophobicity as well as superior gas-sensing characteristics.

scholarly journals Hydrogen gas sensing using aluminum doped ZnO metasurfaces

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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