Palladium-Functionalized Nanostructured Platforms for Enhanced Hydrogen Sensing
TL;DR: In this article, the authors explore several means of fabricating nanostructured films and evaluating their sensing characteristics, such as Palladium-sputtered nanoprocessors.
Abstract: This paper reports on miniaturized hydrogen sensing platforms, exploring several means of fabricating nanostructured films and evaluating their sensing characteristics. Palladium-sputtered nanoporo...
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01 Aug 2021
TL;DR: In this paper, a novel hybrid composite film fabricated with the amalgamation of metal, semiconductor and polymers for hydrogen sensing application at room temperature is reported, which is performed using the hydrothermal synthesis technique.
Abstract: In this work, we report unique hybrid composite film fabricated with the amalgamation of metal, semiconductor and polymers for hydrogen sensing application at room temperature. Fabrication of a novel nanocomposite film based on tin oxide (SnO2) nanosheets with polyaniline (PANI) doped with palladium (Pd) is performed using the hydrothermal synthesis technique. Functional aspects of the fabricated films are investigated with XRD, Raman spectra, FESEM, and FTIR spectral analysis. Interactions of the H2 gas molecules with SnO2, SnO2-Pd, PANI, PANI-SnO2, PANI-SnO2-Pd nanocomposite are also theoretically studied. Using first-principles density functional theory, the effects of gas adsorption on the electronic and transport properties of the sensor are examined. The computations show that the sensitivity of the SnO2 to the H2 gas molecules is considerably improved after hybridisation with Pd and, the sensitivity of the PANI to the H2gas molecules is considerably improved after hybridisation with SnO2.Gas sensing characteristics of fabricated films of SnO2, PANI and composite of SnO2/PANI/Pd are also experimentally investigated at room temperature with varying concentration level ranging from 50 to 400 ppm. The highest sensitivity among all the films at room temperature has been observed as ~540% for the SnO2/Pd film at 0.4% of the target gas and performance factor (the ratio of response percentage to total cycle time) is evaluated highest in Pd doped PANI-SnO2 film. Our results reveal the promising future of SnO2, PANI and Pd associated hybrid films in the development of ultra-high sensitive gas sensors.
32 citations
01 Jan 2021
TL;DR: In this article, hydrogen sensing characteristics of reduced graphene oxide (rGO) based functional nanomaterials are investigated with first principle calculations and experimental analysis, and the influence of gas adsorption on the electronic features of the functional nanostructures are analyzed using first principles density functional theory.
Abstract: In this work, hydrogen sensing characteristics of reduced graphene oxide (rGO) based functional nanomaterials are investigated with first principle calculations and experimental analysis. rGO doped with zinc oxide nanomaterial (i.e. rGO-ZnO), rGO-ZnO with silver nanoparticles (rGO-ZnO-Ag), rGO-ZnO with zirconium oxide (rGO-ZnO-ZrO2), rGO-ZnO doped with silver and palladium (rGO-ZnO-Ag-Pd) are investigated for their sensing capabilities. The influence of gas adsorption on the electronic features of the functional nanostructures are analyzed using the first principles density functional theory. The results of the computation reveal a considerable improvement of graphene oxide sensitivity in the hydrogen gas molecules following hybridization by ZnO, ZnO–Ag, ZnO–Ag–Pd and ZrO2. Fabrication and characterization of aforementioned functional materials and their hydrogen sensing performances are performed and essential sensing characteristics viz., sensitivity, response time, recovery time, reproducibility are also investigated. Out of the fabricated films, rGO-ZnO-Ag-Pd film is found to have the highest sensitivity towards hydrogen. It showed the sensitivity of ∼60% and highest performance factor (evaluated as the ratio of sensitivity to cycle time) among all films, including response time as 10 s and recovery time as 14 s. While performing sensing investigation, the distinct p-type behavior was observed for all the fabricated film. Obtained outcomes relate the promising future of rGO doped ZnO–Ag, ZnO–Ag–Pd and ZrO2 hybrid nano sensor in the advancement of sensitive gas sensors.
28 citations
TL;DR: In this article, the authors reported an excellent gas sensing performance of the unique nanocomposite films prepared with the help of different materials such as semiconductor metaloxide, polymer and metal for carbon monoxide gas sensing at ambient temperature.
Abstract: In the present work, we report an excellent gas sensing performance of the unique nanocomposite films prepared with the help of different materials such as semiconductor metal-oxide, polymer and metal for carbon monoxide gas sensing at ambient temperature. The fabrication of SnO2/PANI/Pd nanocomposite film was performed using the hydrothermal route. The fabricated films were characterized with various analytical techniques such as X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), and Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) etc. Furthermore, DFT results are used to examine the transport and electronic properties of all prepared films. The computing results show that after hybridizing with Pd and SnO2, the response of the fabricated SnO2 and polyaniline (PANI) films to CO gas molecules is considerably improved. At room temperature, sensing characterization of the fabricated sensing films was carried out by using target gas concentrations with varying ppm level of 50–300. At ambient temperature, the SnO2/PANI/Pd film has the maximum sensitivity ~ 400.8% out of all the fabricated films at 0.3% of the target gas. Our findings show that SnO2, SnO2/Pd, PANI, and SnO2/PANI/Pd composite sensing films have a bright future in the gas sensing application with incredibly-higher sensitivity towards CO gas.
21 citations
TL;DR: In this paper, the adsorption characteristics of H2 molecules on the surface of Pd-doped and Pddecorated graphene have been investigated using density functional theory (DFT) calculations to explore the sensing capabilities.
Abstract: The adsorption characteristics of H2 molecules on the surface of Pd-doped and Pd-decorated graphene (G) have been investigated using density functional theory (DFT) calculations to explore the sensing capabilities of Pd-doped/decorated graphene. In this analysis, electrostatic potential, atomic charge distribution, 2D and 3D electron density contouring, and electron localization function projection, were investigated. Studies have demonstrated the sensing potential of both Pd-doped and Pd-decorated graphene to H2 molecules and have found that the gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), i.e., the HOMO-LUMO gap (HLG), decreases to 0.488 eV and 0.477eV for Pd-doped and Pd-decorated graphene, respectively. When H2 is adsorbed on these structures, electrical conductivity increases for both conditions. Furthermore, chemical activity and electrical conductivity are higher for Pd-decorated G than Pd-doped G, whereas the charge transfer of Pd-doped graphene is far better than that of Pd-decorated graphene. Also, studies have shown that the adsorption energy of Pd-doped graphene (−4.3 eV) is lower than that of Pd-decorated graphene (−0.44 eV); a finding attributable to the fact that the recovery time for Pd-decorated graphene is lower compared to Pd-doped graphene. Therefore, the present analysis confirms that Pd-decorated graphene has a better H2 gas sensing platform than Pd-doped graphene and, as such, may assist the development of nanosensors in the future.
18 citations
TL;DR: In this paper, a detailed discussion has been carried out to understand critical steps involved in the fabrication of the silicon-based MEMS resonator and some challenges starting from the materials' selection to the final phase of obtaining a compact MEMS resonance device for its fabrication have been explored critically.
16 citations
References
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TL;DR: In this paper, ZnO nanowires gas sensors were fabricated with microelectromechanical system technology and ethanol-sensing characteristics were investigated, and the sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 300°C.
Abstract: Based on the achievement of synthesis of ZnO nanowires in mass production, ZnO nanowires gas sensors were fabricated with microelectromechanical system technology and ethanol-sensing characteristics were investigated. The sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 300 °C. Our results demonstrate the potential application of ZnO nanowires for fabricating highly sensitive gas sensors.
1,938 citations
"Palladium-Functionalized Nanostruct..." refers background in this paper
...By contrast, major limitations in metal oxides-based sensing platforms are their high working temperatures and low specificity of detection, particularly among similar target species [16-20]....
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TL;DR: Hydrogen sensors and hydrogen-activated switches were fabricated from arrays of mesoscopic palladium wires fabricated by electrodeposition onto graphite surfaces and transferred onto a cyanoacrylate film.
Abstract: Hydrogen sensors and hydrogen-activated switches were fabricated from arrays of mesoscopic palladium wires. These palladium "mesowire" arrays were prepared by electrodeposition onto graphite surfaces and were transferred onto a cyanoacrylate film. Exposure to hydrogen gas caused a rapid (less than 75 milliseconds) reversible decrease in the resistance of the array that correlated with the hydrogen concentration over a range from 2 to 10%. The sensor response appears to involve the closing of nanoscopic gaps or "break junctions" in wires caused by the dilation of palladium grains undergoing hydrogen absorption. Wire arrays in which all wires possessed nanoscopic gaps reverted to open circuits in the absence of hydrogen gas.
1,315 citations
"Palladium-Functionalized Nanostruct..." refers background in this paper
...Resistance increase is proportional to the atomic fraction of absorbed hydrogen atoms to Pd atoms [26-28]....
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TL;DR: In this paper, a polyethyleneimine coating is applied to nanotubes for detecting NO2 at less than 1 ppb (parts-per-billion) concentrations while being insensitive to NH3.
Abstract: Arrays of electrical devices with each comprising multiple single-walled carbon nanotubes (SWNT) bridging metal electrodes are obtained by chemical vapor deposition (CVD) of nanotubes across prefabricated electrode arrays. The ensemble of nanotubes in such a device collectively exhibits large electrical conductance changes under electrostatic gating, owing to the high percentage of semiconducting nanotubes. This leads to the fabrication of large arrays of low-noise electrical nanotube sensors with 100% yield for detecting gas molecules. Polymer functionalization is used to impart high sensitivity and selectivity to the sensors. Polyethyleneimine coating affords n-type nanotube devices capable of detecting NO2 at less than 1 ppb (parts-per-billion) concentrations while being insensitive to NH3. Coating Nafion (a polymeric perfluorinated sulfonic acid ionomer) on nanotubes blocks NO2 and allows for selective sensing of NH3. Multiplex functionalization of a nanotube sensor array is carried out by microspotti...
1,063 citations
1,010 citations
"Palladium-Functionalized Nanostruct..." refers background in this paper
...) have so far been explored for obtaining highly sensitive, reconditionable, efficient, miniaturized gas sensing elements [1-8]....
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TL;DR: In this paper, a critical parameter analysis of different metal oxides that are known to be sensitive to various gaseous species are thoroughly examined, such as phase of the oxide, sensing gas species, operating temperature range, and physical form of the material for the development of integrated gas sensors.
Abstract: In the recent past a great deal of research efforts were directed toward the development of miniaturized gas-sensing devices, particularly for toxic gas detection and for pollution monitoring. Though various techniques are available for gas detection, solid state metal oxides offer a wide spectrum of materials and their sensitivities for different gaseous species, making it a better choice over other options. In this article a critical parameter analysis of different metal oxides that are known to be sensitive to various gaseous species are thoroughly examined. This includes phase of the oxide, sensing gaseous species, operating temperature range, and physical form of the material for the development of integrated gas sensors. The oxides that are covered in this study include oxides of aluminum, bismuth, cadmium, cerium, chromium, cobalt, copper, gallium, indium, iron, manganese, molybdenum, nickel, niobium, ruthenium, tantalum, tin, titanium, tungsten, vanadium, zinc, zirconium, and the mixed or...
953 citations
"Palladium-Functionalized Nanostruct..." refers background in this paper
...The heterojunction leads to band bending in the depletion layers [52]....
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