scholarly journals Adsorption and gas sensing properties of CuFe2O4 nanoparticles

2019 ◽  
Vol 37 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Mohammad Abu Haija ◽  
Georgia Basina ◽  
Fawzi Banat ◽  
Ahmad I. Ayesh
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Spinel Ferrite ◽  
Ferrite Nanoparticles ◽  
Grid Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Gas Sensing Properties

AbstractSpinel ferrite nanoparticles in the form CuFe2O4 were tested for gas sensing applications. Nanoparticles pressed in a disk form were used to construct conductometric gas sensors. The disk was placed between two electrical electrodes wherein the top electrode had a grid structure. The produced sensors were tested against H2S and H2 gases and they were found to be selective and sensitive to H2S concentration as low as 25 ppm. The composition of the nanoparticles was confirmed by X-ray diffraction and energy dispersive X-ray spectroscopy measurements. The crystal structure was verified by both X-ray diffraction and transmission electron microscope. The observations obtained from the experiments demonstrated the high potential of using CuFe2O4 nanoparticles for H2S sensing applications.

A Novel Tungsten Trioxide Based Gas Sensor for Indoor Formaldehyde Detection

2021 ◽  
Vol 16 (3) ◽  
pp. 363-367
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Tao Tian ◽  
Shanyu Liu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Gas Sensor ◽  
Indoor Air ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Material ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Gas Response

Accurate and real-time detection of formaldehyde (HCHO) in indoor air is urgently needed for human health. In this work, a ceramic material (WO3·H2O) with unique structure was successfully prepared using an efficient hydrothermal method. The crystallinity, morphology and microstructure of the as-prepared sensing material were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) as well as transmission electron microscope (TEM). The characterization results suggest that the as-prepared sample is composed of square-like nanoplates with uneven surface. Formaldehyde vapor is utilized as the target gas to investigate gas sensing properties of the synthesized novel nanoplates. The testing results indicate that the as-fabricated gas sensor exhibit high gas response and excellent repeatability to HCHO gas. The response value (Ra/Rg) is 24.5 towards 70 ppm HCHO gas at 350 °C. Besides, the gas sensing mechanism was described.

scholarly journals Fabrication of H2S gas sensors using ZnxCu1-xFe2O4 nanoparticles

2020 ◽  
Vol 126 (7) ◽  
Author(s):  
Mohammad Abu Haija ◽  
Mariem Chamakh ◽  
Israa Othman ◽  
Fawzi Banat ◽  
Ahmad I. Ayesh
Keyword(s):  
Gas Sensors ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Ferrite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion ◽  
Multiple Cycles ◽  
Cubic Structure ◽  
Combustion Technique

Abstract Spinel ferrite nanoparticles can be easily retrieved and utilized for multiple cycles due to their magnetic properties. In this work, nanoparticles of a ZnxCu1-xFe2O4 composition were synthesized by employing a sol–gel auto-combustion technique. The morphology, composition, and crystal structure were examined using scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The produced nanoparticles are in the range of 30–70 nm and manifest spinel cubic structure. The nanoparticles were tested for their sensitivity to H2 and H2S gases, and the Cu-based spinel ferrite nanoparticles were found the most sensitive and selective to H2S gas. Their enhanced response to H2S gas was attributed to the production of metallic CuFeS2 that manifest higher electrical conductivity as compared with CuFe2O4. The fabricated sensors are functional at low temperatures, and consequently, they need low operational power. They are also simple to fabricate with appropriate cost.

A Metastable Ion (III) Oxide Phase (ε-Fe2O3): Preparation and Gas Sensing Properties

2016 ◽  
Vol 697 ◽  
pp. 737-740 ◽  
Author(s):  
Ming Jing Wang ◽  
Hui Ming Ji ◽  
Ya Lu Chen ◽  
Qian Qian Jia
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Sol Gel ◽  
Oxide Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Addition Amount ◽  
Scanning Electron

ε-Fe2O3 is a rare and metastable iron (III) oxide phase. ε-Fe2O3/SiO2 composites were prepared by combining the reverse-micelle and sol-gel methods. An appropriate amount of Ba2+ was needed in this system to promote the formation of ε-Fe2O3 nanorods in SiO2. The size of nanorods varied with different Ba2+ addition amount and sintering procedure. Then pure ε-Fe2O3 nanorods were obtained after stripping SiO2 by etching due to NaOH aqueous solution. The as-synthesized ε-Fe2O3 nanorods were discussed using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Interestingly, metastable ε-Fe2O3 nanorods showed a promising performance for the response for ethanol, compared with the stable phases of α-Fe2O3 and γ-Fe2O3. It indicates that nanostructure ε-Fe2O3 (including ε-Fe2O3 nanorods) could be a valuable material for the fabrication of advanced sensing devices.

scholarly journals Effect of Growth Temperature and Time on Morphology and Gas Sensitivity of Cu2O/Cu Microstructures

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ling Wu ◽  
Lun Zhang ◽  
Zhipeng Xun ◽  
Guili Yu ◽  
Liwei Shi
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Range ◽  
Gas Response

A facile hydrothermal synthesis with CuSO4as the copper source was used to prepare micro/nano-Cu2O. The obtained samples have been characterized by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). With increasing the reaction temperature and time, the final products were successively Cu2O octahedron microcrystals, Cu2O/Cu composite particles, and a wide range of Cu spherical particles. The gas sensitivity of products towards ethanol and acetone gases was studied. The results showed that sensors prepared with Cu2O/Cu composites synthesized at 65°C for 15 min exhibited optimal gas sensitivity. The gas sensing mechanism and the effect of Cu in the enhanced gas response were also elaborated. The excellent gas sensitivity indicates that Cu2O/Cu composites have potential application as gas sensors.

scholarly journals Thermolysis of sprayed suspensions for obtaining highly spinel ferrite nanoparticles

2019 ◽  
pp. 14-21
Author(s):  
Elena G. Petrova ◽  
Yana A. Shavshukova ◽  
Dzmitry A. Kotsikau ◽  
Kazimir I. Yanushkevich ◽  
Konstantin V. Laznev ◽  
...  
Keyword(s):  
Annealing Temperature ◽  
Spinel Ferrite ◽  
Ferrite Nanoparticles ◽  
Specific Magnetization ◽  
X Ray Diffraction ◽  
Crystallinity Degree ◽  
Insulating Layer ◽  
X Ray ◽  
Transmission Electron ◽  
Before And After

Thermal treatment of ferrite magnetic nanoparticles in NaCl matrix gives an opportunity to increase their specific magnetization with preservation of nanoscale size. Composite materials based on mixed ferrites Co0.65Zn0.35Fe2O4 and Mg 0.5Zn0.5Fe2O4 were synthesized by spray-drying of aqueous suspensions in presence of NaCl and annealed at 300 –900 °C. The microstructure and phase composition of nanoparticles before and after annealing were studied by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction analysis and IR spectroscopy. The magnetic properties of nanoparticles were estimated using a ponderomotive method of measuring the specific magneti zation at room temperature in a magnetic field with an induction of 0.86 T. The increase of the annealing temperature up to 900 °C was established to lead to the increase in the specific magnetization of ferrites – from 32.79 to 91.3 emu/g (Co0.65Zn0.35Fe2O4) and from 2.76 to 22.31 emu/g (Mg 0.5 Zn 0.5Fe2O4) due to recrystallization processes and increase of crystallinity degree of the ferrites. Due to the NaCl insulating layer, the particle size increases just slightly (from ~ 10 nm before annealing to ~ 60 nm after annealing at 900 °C). This method is effective for substantial increase in specific magnetization of ferrite nanoparticles with preservation of their nanoscale size.

The Characterization and Gas Sensing Properties of Polythiophene Coated V2O5 Nanotubes

2010 ◽  
Vol 654-656 ◽  
pp. 1154-1157 ◽  
Author(s):  
Yu Lu ◽  
Wei Jin ◽  
Wen Chen
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Higher Sensitivity

Polythiophene (PTP) coated V2O5 nanotubes were prepared by an in-situ polymerization of thiophene monomers in the presence of prepared V2O5 nanotubes. The nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which proved the polymerization of thiophene monomer and the strong interaction between polythiophene and V2O5 nanotubes (VONTs). The gas sensing properties of PTP coated V2O5 nanotubes were studied at room temperature, which was found that PTP coated V2O5 nanotubes could detect ethanol with much higher sensitivity than pure VONTs. The sensing mechanism of PTP coated V2O5 nanotubes to ethanol is presumed to be the synergetic interaction between polythiophene (PTP) and V2O5 nanotubes.

scholarly journals Synthesis and acetone sensing properties of ZnFe2O4/rGO gas sensors

2019 ◽  
Vol 10 ◽  
pp. 2516-2526 ◽  
Author(s):  
Kaidi Wu ◽  
Yifan Luo ◽  
Ying Li ◽  
Chao Zhang
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Hollow Spheres ◽  
High Sensitivity ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene

Hollow spheres of pure ZnFe2O4 and of composites of ZnFe2O4 and reduced graphene oxide (rGO) with different rGO content were prepared via a simple solvothermal method followed by a high-temperature annealing process in an inert atmosphere. The X-ray diffraction analysis confirmed that the introduction of rGO had no effect on the spinel structure of ZnFe2O4. In addition, the results of field-emission scanning electron microscopy and (high-resolution) transmission electron microscopy indicated that the synthesized samples had the structure of hollow spheres distributed uniformly onto rGO nanosheets. The diameters of the spheres were determined as about 600–1000 nm. The gas sensing test revealed that the introduction of rGO improved the performance of the sensing of acetone to low concentration, and the ZnFe2O4/rGO composite gas sensor containing 0.5 wt % of rGO exhibited a high sensitivity in sensing test using 0.8–100 ppm acetone at 200 °C. The response of the 0.5 wt % ZnFe2O4/rGO sensor to 0.8 ppm acetone was 1.50, and its response to 10 ppm acetone was 8.18, which is around 2.6 times more pronounced than the response of pure ZnFe2O4 (10 ppm, 3.20). Moreover, the sensor showed a wide linear range and good selectivity.

scholarly journals A comparative study on the electrical and gas sensing properties of thick films prepared with synthesized nano-sized and commercial micro-sized Fe2O3 powders

2017 ◽  
Vol 11 (4) ◽  
pp. 265-274 ◽  
Author(s):  
Ali Mirzaei ◽  
Maryam Bonyani ◽  
Shahab Torkian ◽  
Mahdi Feizpour ◽  
Anna Bonavita ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Thick Films ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Underlying Mechanisms

In this work, Fe2O3 nanoparticles (NPs) were successfully synthesized by Pechini sol-gel method. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction characterizations were used to study the morphology and crystal structure of the synthesized products. The electrical and gas sensing behaviour of the synthesized and commercial Fe2O3 samples, prepared in the form of thick films, were studied. Though the commercial Fe2O3 powders had lower resistance but it was found that the synthesized Fe2O3 NPs had better gas sensing properties. The underlying mechanisms are discussed in details. The present findings show advantages of Fe2O3 NPs over micro-size particles for gas sensing applications.

Tungsten Sulfide Nanoflakes: Synthesis by Electrospinning and Their Gas Sensing Properties

2017 ◽  
Vol 72 (4) ◽  
pp. 375-381 ◽  
Author(s):  
Ke Wang ◽  
Wen-Lin Feng ◽  
Xiang Qin ◽  
Da-Shen Deng ◽  
Xu Feng ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Threshold Value ◽  
Group Symmetry ◽  
X Ray Diffraction ◽  
Tungsten Sulfide ◽  
X Ray ◽  
Surface Control ◽  
Gas Sensing Properties ◽  
Calcination Method

AbstractTungsten sulfide (WS2) nanoflakes were successfully prepared via electrospinning with polyvinylpyrrolidone (PVP) as organic solvent. In addition, Ag-deposited WS2 (Ag-WS2) was obtained by chemical blending/calcination method. The structure and morphology of as-prepared materials were characterised by powder X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The XRD result shows that the prepared WS2 has a graphene-like structure with P63/mmc space group symmetry. The SEM illuminates that the sensing samples have nanoflake appearance. Furthermore, heater-type gas sensors were fabricated based on WS2 and Ag-WS2 nanomaterials. The sensing responses of WS2 and Ag-WS2 on the ammonia (NH3), ethanol (C2H5OH), and acetone (C3H6O) were investigated at about 220°C. The results indicate that gas sensor based on WS2 and Ag-WS2 nanoflakes has 60 ppm sensing threshold value for ammonia. One possible gas sensing mechanism of WS2 and Ag-WS2 gas sensors is surface control via charge transfer.

Polyaniline/SnO2 Nanocomposite Sensor for NO2 Gas Sensing at Low Operating Temperature

2015 ◽  
Vol 14 (04) ◽  
pp. 1550011 ◽  
Author(s):  
A. Sharma ◽  
M. Tomar ◽  
V. Gupta ◽  
A. Badola ◽  
N. Goswami
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Sensing Properties ◽  
Response Recovery ◽  
Transmission Electron ◽  
Gas Sensing Properties

In this paper gas sensing properties of 0.5–3% polyaniline (PAni) doped SnO 2 thin films sensors prepared by chemical route have been studied towards the trace level detection of NO 2 gas. The structural, optical and surface morphological properties of the PAni doped SnO 2 thin films were investigated by performing X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Raman spectroscopy measurements. A good correlation has been identified between the microstructural and gas sensing properties of these prepared sensors. Out of these films, 1% PAni doped SnO 2 sensor showed high sensitivity towards NO 2 gas along with a sensitivity of 3.01 × 102 at 40°C for 10 ppm of gas. On exposure to NO 2 gas, resistance of all sensors increased to a large extent, even greater than three orders of magnitude. These changes in resistance upon removal of NO 2 gas are found to be reversible in nature and the prepared composite film sensors showed good sensitivity with relatively faster response/recovery speeds.

Sign in / Sign up

Export Citation Format

Share Document