scholarly journals Hydrothermal Growth and Hydrogen Selective Sensing of Nickel Oxide Nanowires

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Thi Thanh Le Dang ◽  
Matteo Tonezzer ◽  
Van Hieu Nguyen
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Low Cost ◽  
Hydrogen Sensor ◽  
Nanostructured Material ◽  
Liquefied Petroleum Gas ◽  
Semiconducting Nanowires ◽  
Response And Recovery ◽  
Nanostructured Metal Oxides ◽  
P Type

Low cost synthesis of nanostructured metal oxides for gas sensing application at low temperature is nowadays of crucial importance in many fields. Herein, NiO p-type semiconducting nanowires with polycrystalline structure were prepared by a facile and scalable hydrothermal method. Morphology and crystal structure of the NiO nanowires were investigated by scan electron microscopy, X-ray diffraction, and transmission electron microscopy. The nanostructured material was then tested as hydrogen sensor showing very good performance in terms of sensor response, stability, absence of drifts, and speed of response and recovery. The selectivity of the NiO sensor to hydrogen towards other gases (ethanol, ammonia, and liquefied petroleum gas) was found to be good.

scholarly journals Electrophoretic deposition of Au NPs on CNT networks for sensitive NO<sub>2</sub> detection

2014 ◽  
Vol 3 (2) ◽  
pp. 245-252 ◽  
Author(s):  
E. Dilonardo ◽  
M. Penza ◽  
M. Alvisi ◽  
C. Di Franco ◽  
D. Suriano ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Spectroscopic Characterization ◽  
Core Diameter ◽  
Au Nps ◽  
Transmission Electron ◽  
P Type ◽  
Reducing Gases ◽  
The Impact

Abstract. In the present study, Au-surfactant core-shell colloidal nanoparticles (NPs) with controlled dimension and composition were synthesized by sacrificial anode electrolysis. Transmission electron microscopy (TEM) revealed that Au NPs core diameter is between 8 and 12 nm, as a function of the electrosynthesis conditions. Moreover, surface spectroscopic characterization by X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of nanosized gold phase. Controlled amounts of Au NPs were then deposited electrophoretically on carbon nanotube (CNT) networked films. The resulting hybrid materials were morphologically and chemically characterized using TEM, SEM (scanning electron microscopy) and XPS analyses, which revealed the presence of nanoscale gold, and its successful deposition on CNTs. Au NP/CNT networked films were tested as active layers in a two-pole resistive NO2 sensor for sub-ppm detection in the temperature range of 100–200 °C. Au NP/CNT exhibited a p-type response with a decrease in the electrical resistance upon exposure to oxidizing NO2 gas and an increase in resistance upon exposure to reducing gases (e.g. NH3). It was also demonstrated that the sensitivity of the Au NP/CNT-based sensors depends on Au loading; therefore, the impact of the Au loading on gas sensing performance was investigated as a function of the working temperature, gas concentration and interfering gases.

The blue luminescence of p-type NiO nanostructured material induced by defects: H2S gas sensing characteristics at a relatively low operating temperature

2020 ◽  
Vol 525 ◽  
pp. 146002 ◽  
Author(s):  
Teboho P. Mokoena ◽  
Zamaswazi P. Tshabalala ◽  
Kenneth T. Hillie ◽  
Hendrik C. Swart ◽  
David E. Motaung
Keyword(s):  
Gas Sensing ◽  
Operating Temperature ◽  
Nanostructured Material ◽  
Blue Luminescence ◽  
P Type ◽  
Sensing Characteristics

Sensing Properties of CNT hybrid MOS-based Sensors

2004 ◽  
Vol 828 ◽  
Author(s):  
Wei-Jen Liou ◽  
Tsung-Yeh Yang ◽  
Kuang-Nan Lin ◽  
Ching-Hong Yang ◽  
Hong-Ming Lin
Keyword(s):  
Electron Microscopy ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
Sol Gel ◽  
Gas Sensitivity ◽  
Sensing Properties ◽  
Operation Temperature ◽  
Transmission Electron ◽  
Lower Temperature ◽  
P Type

ABSTRACTThe carbon nanotubes provide large surface that can enhance the gas adsorption properties and increase the conductivity at a lower temperature for gas sensing. The gas sensing properties of the hybrid TiO2/CNTs material are examined in this study. The sol-gel technique is used to prepare a thin layer of nano-TiO2 coated on CNTs. The structure of TiO2/CNTs hybrid materials is identified by X-ray diffraction (XRD) and Raman spectrum. The granules and surface morphology are analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrical properties of the hybrid TiO2/CNTs indicate that the operation temperature can be lowered to ambient temperature and this will enhance the gas sensitivity for detecting CO gas. The n-type or p-type behavior of hybrid TiO2/CNTs can be controlled by the coating thickness of hybrid TiO2. According to the image results, the mechanisms of the n-type and p-type behavior of hybrid TiO2/CNTs system are proposed.

scholarly journals Incorporating N Atoms into SnO2 Nanostructure as an Approach to Enhance Gas Sensing Property for Acetone

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 445 ◽  
Author(s):  
Xiangfeng Guan ◽  
Yongjing Wang ◽  
Peihui Luo ◽  
Yunlong Yu ◽  
Dagui Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensor ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Gas Sensing ◽  
Diffuse Reflectance Spectroscopy ◽  
Limit Of Detection ◽  
Low Cost ◽  
X Ray ◽  
Sno2 Nanostructure

The development of high-performance acetone gas sensor is of great significance for environmental protection and personal safety. SnO2 has been intensively applied in chemical sensing areas, because of its low cost, high mobility of electrons, and good chemical stability. Herein, we incorporated nitrogen atoms into the SnO2 nanostructure by simple solvothermal and subsequent calcination to improve gas sensing property for acetone. The crystallization, morphology, element composition, and microstructure of as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR), Raman spectroscopy, UV–visible diffuse reflectance spectroscopy (UV–vis DRS), and the Brunauer–Emmett–Teller (BET) method. It has been found that N-incorporating resulted in decreased crystallite size, reduced band-gap width, increased surface oxygen vacancies, enlarged surface area, and narrowed pore size distribution. When evaluated as gas sensor, nitrogen-incorporated SnO2 nanostructure exhibited excellent sensitivity for acetone gas at the optimal operating temperature of 300 °C with high sensor response (Rair/Rgas − 1 = 357) and low limit of detection (7 ppb). The nitrogen-incorporated SnO2 gas sensor shows a good selectivity to acetone in the interfering gases of benzene, toluene, ethylbenzene, hydrogen, and methane. Furthermore, the possible gas-sensing mechanism of N-incorporated SnO2 toward acetone has been carefully discussed.

scholarly journals High Sensitivity of Ammonia Sensor through 2D Black Phosphorus/Polyaniline Nanocomposite

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3026
Author(s):  
Zuquan Wu ◽  
Lei Liang ◽  
Shibu Zhu ◽  
Yifan Guo ◽  
Yao Yao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Low Cost ◽  
Oxidative Polymerization ◽  
High Sensitivity ◽  
Fast Response ◽  
Experimental Result ◽  
Conjugation System ◽  
Detection Range ◽  
Sensing Material ◽  
Response And Recovery

Recently, as a two-dimensional (2D) material, black phosphorous (BP) has attracted more and more attention. However, few efforts have been made to investigate the BP/polyaniline (PANI) nanocomposite for ammonia (NH3) gas sensors. In this work, the BP/PANI nanocomposite as a novel sensing material for NH3 detection, has been synthesized via in situ chemical oxidative polymerization, which is then fabricated onto the interdigitated transducer (IDTs). The electrical properties of the BP/PANI thin film are studied in a large detection range from 1 to 4000 ppm, such as conduction mechanism, response, reproducibility, and selectivity. The experimental result indicates that the BP/PANI sensor shows higher sensitivity and larger detection range than that of PANI. The BP added into PANI, that may enlarge the specific surface area, obtain the special trough structure for gas channels, and form the p–π conjugation system and p–p isotype heterojunctions, which are beneficial to increase the response of BP/PANI to NH3 sensing. Meanwhile, in order to support the discussion result, the structure and morphology of the BP/PANI are respectively measured by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV−vis), transmission electron microscopy (TEM), and field emissions scanning electron microscopy (SEM). Moreover, the sensor shows good reproducibility, and fast response and recovery behavior, on NH3 sensing. In addition, this route may offer the advantages of an NH3 sensor, which are of simple structure, low cost, easy to assemble, and operate at room temperature.

scholarly journals Получение нанокомпозитов МУНТ/MnO-=SUB=-2-x-=/SUB=-, МУНТ/MnO-=SUB=-2-x-=/SUB=-/CuO и исследования их газочувствительных свойств

2019 ◽  
Vol 61 (11) ◽  
pp. 2240
Author(s):  
Ю.А. Стенькин ◽  
В.В. Болотов ◽  
Д.В. Соколов ◽  
В.Е. Росликов ◽  
К.Е. Ивлев
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Gas Sensing ◽  
Multiwalled Carbon ◽  
X Ray ◽  
P Type ◽  
Scanning Electron

Nanocomposites based on multiwalled carbon nanotubes (MWCNT) with manganese dioxide (MnO2-x) and copper oxide (CuO) were obtained and investigated. The morphology and elemental composition of MWCNT-layer and nanocomposites MWCNT/MnO2-х, MWCNT/MnO2-х/CuO were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing response of MWCNT-layer and nanocomposites upon exposure to hydrogen sulfide (H2S) and nitrogen dioxide (NO2) was demonstrated at room temperature. Effect of increasing the conductivity of MWCNT-layer and nanocomposites upon exposure to NO2 indicates these nanomaterials have conductive of p-type. Copper oxide in nanocomposite significantly enhances the gas sensing response to H2S.

scholarly journals Reversible Room Temperature H2 Gas Sensing Based on Self-Assembled Cobalt Oxysulfide

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 303
Author(s):  
Hui Zhou ◽  
Kai Xu ◽  
Nam Ha ◽  
Yinfen Cheng ◽  
Rui Ou ◽  
...  
Keyword(s):  
Room Temperature ◽  
Elevated Temperatures ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Cobalt Sulfide ◽  
Bandgap Energy ◽  
Gas Molecules ◽  
Self Assembled ◽  
P Type

Reversible H2 gas sensing at room temperature has been highly desirable given the booming of the Internet of Things (IoT), zero-emission vehicles, and fuel cell technologies. Conventional metal oxide-based semiconducting gas sensors have been considered as suitable candidates given their low-cost, high sensitivity, and long stability. However, the dominant sensing mechanism is based on the chemisorption of gas molecules which requires elevated temperatures to activate the catalytic reaction of target gas molecules with chemisorbed O, leaving the drawbacks of high-power consumption and poor selectivity. In this work, we introduce an alternative candidate of cobalt oxysulfide derived from the calcination of self-assembled cobalt sulfide micro-cages. It is found that the majority of S atoms are replaced by O in cobalt oxysulfide, transforming the crystal structure to tetragonal coordination and slightly expanding the optical bandgap energy. The H2 gas sensing performances of cobalt oxysulfide are fully reversible at room temperature, demonstrating peculiar p-type gas responses with a magnitude of 15% for 1% H2 and a high degree of selectivity over CH4, NO2, and CO2. Such excellent performances are possibly ascribed to the physisorption dominating the gas–matter interaction. This work demonstrates the great potentials of transition metal oxysulfide compounds for room-temperature fully reversible gas sensing.

Organic/Inorganic Nanocomposite for Enhancement of H2S Gas Sensor

2019 ◽  
Vol 25 ◽  
pp. 12-21
Author(s):  
Isam M. Ibrahim ◽  
Shahad Issam Sharhan
Keyword(s):  
Gas Sensing ◽  
Low Cost ◽  
Conductive Polymer ◽  
Volume Ratio ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
Average Roughness ◽  
Atomic Force ◽  
Nanocomposite Thin Films ◽  
Response And Recovery

This work presents improvement of H2S gas sensing capability by introducing TiO2 in conductive polymer namely “MEH-PPV”. Firstly, the organic conjugated polymer poly ( 2-methoxy-5- ( 2'-ethythexyloxy) - 1,4-phenlenevinylene) and TiO2 was dissolved in chloroform solvent. The two solutions “MEH-PPV” and TiO2 were mixed in a volume ratio of (0.002 and 0.008) respectively and spin-coated on Si substrate for realizing facile and low-cost sensors. The X-Ray diffraction spectrum of (MEH-PPV/TiO2) nanocomposite thin films was studied, all the pattern showed that the structure is amorphous. The morphology was demonstrated by Field Emission Scanning Electron Microscope (FESEM) images for MEH-PPV and MEH-PPV/TiO2 films which shows formed anano flower like structure with introduces of TiO2All films were examined by Atomic Force Microscope (AFM) which revealed the average roughness increment from 0.204 to 1.25 nm with increase the mixed rate of TiO2. The “MEH-PPV/TiO2” based sensors also shown noticeable responses when the sensors exposure to H2S gas at the concentration of 25ppm. The maximum sensitivity for MEH-PPV/(0.008) TiO2 was 528.1 at operating temperature at 100°C, whereas the response and recovery time was ~ 21.5 s and ~3.8 s, respectively.

scholarly journals Highly sensitive and room temperature detection of ultra-low concentrations of O3 using self-powered sensing elements of Cu2O nanocubes

2019 ◽  
Vol 1 (5) ◽  
pp. 2009-2017 ◽  
Author(s):  
E. Petromichelaki ◽  
E. Gagaoudakis ◽  
K. Moschovis ◽  
L. Tsetseris ◽  
T. D. Anthopoulos ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
New Class ◽  
Temperature Detection ◽  
Low Concentrations ◽  
Highly Sensitive ◽  
Self Powered ◽  
P Type

The fundamental development of the design of novel self-powered ozone sensing elements, operating at room temperature, based on p-type metal oxides paves the way to a new class of low cost, highly promising gas sensing devices.

ENHANCED GAS SENSING PROPERTIES OF p-TYPE TeO2 NANORODS FUNCTIONALIZED WITH Pd

NANO ◽  
2011 ◽  
Vol 06 (05) ◽  
pp. 455-460 ◽  
Author(s):  
HYUNSU KIM ◽  
SUNGHOON PARK ◽  
CHANGHYUN JIN ◽  
CHONGMU LEE
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Average Diameter ◽  
Pd Nanoparticles ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Face Centered ◽  
P Type

TeO2 nanorods functionalized with Pd were prepared by a three-step process comprising thermal evaporation of Te powders, Pd deposition by photo-reduction, and annealing. Sensors were fabricated by using the Pd -functionalized TeO2 nanorods. Scanning electron microscopy images exhibited that the nanorods with diameters in a range of 50–100 nm and lengths of a few micrometers were covered with the Pd nanoparticles with an average diameter of ~ 15 nm. Transmission electron microscopy and X-ray diffraction analysis revealed that the nanorods were monocrystalline simple tetragonal TeO2 . On the other hand, the nanoparticles on them were confirmed to be nanocrystalline face-centered cubic Pd . The multiple-networked TeO2 nanorod sensors exhibited a sensitivity of 3.13% at 100 ppm NO2 at 300°C, whereas the Pd -functionalized TeO2 nanorod sensors exhibited a sensitivity of 11.97% under the same condition. The recovery time of TeO2 nanorods was decreased considerably at every NO2 concentration by the Pd -functionalization even if the response time decreased or increased slightly depending upon the NO2 concentration. In addition, the origin of the enhancement of the sensing properties of the TeO2 nanorods by functionalization with Pd is discussed.

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