scholarly journals A Hydrogen Gas Sensor Based on TiO2 Nanoparticles on Alumina Substrate

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2483 ◽  
Author(s):  
Siti Mohd Chachuli ◽  
Mohd Hamidon ◽  
Md. Mamat ◽  
Mehmet Ertugrul ◽  
Nor Abdullah
Keyword(s):  
Tio2 Nanoparticles ◽  
Gas Sensor ◽  
Operating Temperature ◽  
Hydrogen Gas ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
X Ray ◽  
Semiconductor Gas Sensor ◽  
Sensing Material ◽  
P Type

High demand of semiconductor gas sensor works at low operating temperature to as low as 100 °C has led to the fabrication of gas sensor based on TiO2 nanoparticles. A sensing film of gas sensor was prepared by mixing the sensing material, TiO2 (P25) and glass powder, and B2O3 with organic binder. The sensing film was annealed at temperature of 500 °C in 30 min. The morphological and structural properties of the sensing film were characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The gas sensor was exposed to hydrogen with concentration of 100–1000 ppm and was tested at different operating temperatures which are 100 °C, 200 °C, and 300 °C to find the optimum operating temperature for producing the highest sensitivity. The gas sensor exhibited p-type conductivity based on decreased current when exposed to hydrogen. The gas sensor showed capability in sensing low concentration of hydrogen to as low as 100 ppm at 100 °C.

scholarly journals Decoration of CuO NWs Gas Sensor with ZnO NPs for Improving NO2 Sensing Characteristics

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2103 ◽  
Author(s):  
Tae-Hee Han ◽  
So-Young Bak ◽  
Sangwoo Kim ◽  
Se Hyeong Lee ◽  
Ye-Ji Han ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Sol Gel ◽  
Oxide Semiconductor ◽  
Zno Nps ◽  
X Ray ◽  
Semiconductor Gas Sensor ◽  
Initial Resistance ◽  
P Type ◽  
Sensing Characteristics

This paper introduces a method for improving the sensitivity to NO2 gas of a p-type metal oxide semiconductor gas sensor. The gas sensor was fabricated using CuO nanowires (NWs) grown through thermal oxidation and decorated with ZnO nanoparticles (NPs) using a sol-gel method. The CuO gas sensor with a ZnO heterojunction exhibited better sensitivity to NO2 gas than the pristine CuO gas sensor. The heterojunction in CuO/ZnO gas sensors caused a decrease in the width of the hole accumulation layer (HAL) and an increase in the initial resistance. The possibility to influence the width of the HAL helped improve the NO2 sensing characteristics of the gas sensor. The growth morphology, atomic composition, and crystal structure of the gas sensors were analyzed using field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy, and X-ray diffraction, respectively.

The xylene sensing performance of WO3 decorated anatase TiO2 nanoparticles as a sensing material for a gas sensor at a low operating temperature

RSC Advances ◽  
2016 ◽  
Vol 6 (55) ◽  
pp. 49692-49701 ◽  
Author(s):  
Nan Chen ◽  
Dongyang Deng ◽  
Yuxiu Li ◽  
Xinxin Xing ◽  
Xu Liu ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Operating Temperature ◽  
Anatase Tio2 ◽  
Sensing Material ◽  
One Step ◽  
Sensing Performance

Here, the pristine and WO3 decorated TiO2 nanoparticles were synthesized by a one-step hydrothermal without the use of a surfactant or template, and used to fabricate gas sensors.

Prepare and Formaldehyde Sensing Properties of Hollow Nanofibers In2O3

2014 ◽  
Vol 941-944 ◽  
pp. 479-482
Author(s):  
Chang Bai Liu ◽  
Xing Yi Liu
Keyword(s):  
Operating Temperature ◽  
Optimum Operating ◽  
Hollow Nanofibers ◽  
Optimum Operating Temperature ◽  
X Ray ◽  
Sensing Properties ◽  
Response And Recovery ◽  
Formaldehyde Sensing ◽  
Hollow Nanofiber ◽  
Synthesized Materials

Hollow nanofiber In2O3 is synthesized by electrospinning. The as-synthesized materials are characterized by scanning electron microscope (SEM) and X-ray power diffraction (XRD). The formaldehyde sensing properties of the devices using In2O3 films are investigated at different operating temperatures. The results reveal that the response of hollow nanofiber In2O3 sensor is about 2.5 to 1 ppm formaldehyde at the optimum operating temperature of 270°C. The response and recovery time is about 3 s and 19 s, respectively. Moreover, sensor possesses a good selectivity to some common gas.

Catalytic Pyrolysis of LDPE Plastic Wastes over Mortar Cement Catalyst

2014 ◽  
Vol 931-932 ◽  
pp. 47-51
Author(s):  
Veeranuch Srakeaw ◽  
Siriporn Yodjai ◽  
Unalome Wetwatana
Keyword(s):  
Catalytic Pyrolysis ◽  
Mixed Oxides ◽  
Operating Temperature ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
X Ray ◽  
Plastic Wastes ◽  
Liquid Products ◽  
Percentage Yield ◽  
Fcc Catalysts

A CaO based catalyst synthesized from mortar previously used in construction was chosen for pyrolysis of LDPE plastic waste. The samples were calcined at temperatures of 500 and 800 °C for comparison purpose. After calcination, two mixed oxides were obtained, denoted as catalyst A and B. The chemical composition of the metal oxide catalysts and the liquid products of the pyrolysis were characterized by X-ray Fluorescence (XRF) and Simulated Distillation - Gas Chromatography (SD-GC), respectively. The XRF analysis indicated that the catalyst, reformed from the mortar cement, consisted of CaO, silica (silicon dioxide, SiO2) and alumina (aluminium (III) oxide, Al2O3) as the main constituents, though, the composition of each compound differed because of the influence of calcination temperature. Catalyst A had 41.96% of CaO, 4.27% of Al2O3 and 30.82% of SiO2 when the catalyst B had 37.04% of CaO, 2.38% of Al2O3 and 37.31% of SiO2. The amount of CaO in the catalyst B was found to be less in catalyst A. The catalyst A gave higher percentage yield of naphtha oil (48±1.14%v/v), compared to catalyst B (21±1.26%v/v). The performance of this catalyst (A) towards the pyrolysis of plastic wastes was compared to commercial grade ZSM-5 and FCC catalysts. It was found that the catalyst A, CaO based catalyst, reformed from the mortar cement, gave the highest yield of naphtha oil (48±1.14%v/v) compared to ZSM-5 (26±1.52%v/v) and FCC (16±1.09%v/v). The optimum operating temperature for the pyrolysis was found at 410 °C (in the temperature range 370 °C to 450 °C) and the optimum catalyst (A) composition was 0.3 %w/w of mortar cement catalyst in LDPE. This optimum condition gave 86.67± 0 %w/w of liquid, 12.49± 0.24 %w/w of gas and 0.84± 0.24 %w/w of solid. The catalyst A showed the best performance amongst all the catalysts towards the pyrolysis process of plastic wastes.

scholarly journals New Comparative Study of High-Sensitivity H2Gas Sensors at Room Temperature Based on ZnO NWs Grown on Si and PS/Si Substrates without Catalyst by Wet Thermal Evaporation Method

2021 ◽  
Vol 2114 (1) ◽  
pp. 012087
Author(s):  
H. I. Abdulgafour ◽  
Thamer A.A. Hassan ◽  
F.K. Yam
Keyword(s):  
Gas Sensor ◽  
Flow Rate ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Specific Area ◽  
Hydrogen Gas ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
High Quality ◽  
Thermal Evaporation Method

Abstract A novel approach for growing high-quality ZnOnano-structures with no catalyst using an inexpensive technique that is called wet thermal evaporation has been investigated for gas sensor applications. For a novel comparative investigation of H2 gas sensors, large regions regarding the well-aligned coral reef-like ZnOnano-structures on the porous Si (PS) and flower-like nano-rods on Silicon were successfully utilized. In the presented study, a Pd/ZnO/Pd metal-semiconductor-metal was efficiently created for H2 gas sensor device employing high-quality ZnOnano-structures that are grown on a variety of the substrates. At room temperature, the sensitivity related to ZnO/PS and ZnO/Si is evaluated at various flow rate values (25sccm, 50sccm, 100sccm, and 150sccm) of 2% H2 gas. The I-V characteristics revealed that ZnO/Si has a larger hydrogen gas barrier height than ZnO/PS. At room temperature, the ZnO/Si sensitivity was about 105% and 190% for ZnO/PS at 150sccm flow rate. The sensors’ sensitivity and optimum operating temperature for ZnO/PS at 150sccm of H2 gas are 350% (at 100 Celsius), which is higher compared to double the maximal sensitivity with regard to ZnO/Si device at a temperature of 150 Celsius. This research concluded that because ZnO/PS has a large specific area, it has a greater possibility of reacting with gases and increasing sensitivity at the temperature of theroom.

Sunflower-Like Zinc Oxide Architectures: The Application of Acetone Gas Sensor for Asphalt Pavement Construction

2021 ◽  
Vol 16 (1) ◽  
pp. 6-10
Author(s):  
Bo Zuo ◽  
Yan Fu ◽  
Gaofeng Deng ◽  
Lingling Qi
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Asphalt Pavement ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Measurement Results ◽  
Gas Sensing Properties ◽  
Pavement Construction ◽  
Gas Response

In this work, hierarchical nanorod-assembled ZnO sunflower-like structures were successfully synthesized through a water bath route. Crystalline phase and surface morphology of as-prepared ZnO were investigated via XRD and SEM techniques, respectively. Gas sensor fabricated from nanorod-assembled ZnO sunflowers was made, which exhibits excellent gas sensing properties at various concentrations of acetone and different operating temperatures. The gas response values at the optimum operating temperature (300 °C) are 49 towards 200 ppm acetone. The sensing measurement results indicates that the as-synthesized ZnO material may depict potential application as an acetone detector in asphalt pavement construction.

Temperature Dependence of Responses in Metal Oxide Gas Sensors

2015 ◽  
Vol 644 ◽  
pp. 181-184 ◽  
Author(s):  
S. Rahbarpour ◽  
S. Sajed ◽  
H. Ghafoorifard
Keyword(s):  
Metal Oxide ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Operating Temperature ◽  
Diffusion Theory ◽  
Gas Diffusion ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Metal Oxide Gas Sensors ◽  
Resistive Gas Sensors

Selecting an optimum operating temperature for metal oxide gas sensors is of prime technical importance. Here, the temperature behavior of various kinds of metal oxide gas sensors in response to different levels of reducing contaminants in air is reported. The examined gas sensor samples include a Tin oxide-based resistive gas sensor and home-made diode-type Ag-TiO2-Ti gas sensors. Recorded response vs. temperature curves of all samples represent two different typical features: The responses related to the resistive gas sensor exhibit distinct maximum response at a well defined operating temperature regardless of the target gas concentration level, but the diode type samples demonstrated a continuously rising response as the operating temperature decreased to highly contaminated atmospheres. At low contaminant levels, diode type gas sensors change their behaviour and act similar to resistive gas sensors. Reported results were described by a model based on the gas diffusion theory.

scholarly journals Improved Sensitivity of α-Fe2O3 Nanoparticle-Decorated ZnO Nanowire Gas Sensor for CO

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1903 ◽  
Author(s):  
Jeongseok Lee ◽  
Se-Hyeong Lee ◽  
So-Young Bak ◽  
Yoojong Kim ◽  
Kyoungwan Woo ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Indium Tin Oxide ◽  
Gas Sensing ◽  
Sol Gel ◽  
Oxide Semiconductor ◽  
Oxide Glass ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
X Ray ◽  
Fe2o3 Nanoparticle

A strategy for improving the sensitivity of a sensor for detecting CO and NH3 gases is presented herein. The gas sensor was fabricated from ZnO metal oxide semiconductor nanostructures grown via a vapor–liquid–solid process and decorated with α-Fe2O3 nanoparticles via a sol–gel process. The response was enhanced by the formation of an α-Fe2O3/ZnO n–n heterojunction and the growth of thinner wires. ZnO nanowires were grown on indium–tin–oxide glass electrodes using Sn as a catalyst for growth instead of Au. The structure and elemental composition were investigated using field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The gas sensing results indicate that the response value to 100 ppm CO was 18.8 at the optimum operating temperature of 300 °C.

scholarly journals Titanium Dioxide-Based64∘YXLiNbO3Surface Acoustic Wave Hydrogen Gas Sensors

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
A. Z. Sadek ◽  
D. Buso ◽  
A. Martucci ◽  
P. Mulvaney ◽  
W. Wlodarski ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Acoustic Wave ◽  
Gas Sensors ◽  
Sol Gel ◽  
Hydrogen Gas ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Helium Atmosphere ◽  
Gas Detectors ◽  
Hydrogen Gas Sensors

Amorphous titanium dioxide (TiO2) and gold (Au) dopedTiO2-based surface acoustic wave (SAW) sensors have been investigated as hydrogen gas detectors. The nanocrystal-dopedTiO2films were synthesized through a sol-gel route, mixing a Ti-butoxide-based solution with diluted colloidal gold nanoparticles. The films were deposited via spin coating onto64∘YXLiNbO3SAW transducers in a helium atmosphere. The SAW gas sensors were operated at various temperatures between 150 and310∘C. It was found that gold doping onTiO2increased the device sensitivity and reduced the optimum operating temperature.

Xylene-sensing of Fe2(MoO4)3 nanoplates prepared via a hydrothermal method

2017 ◽  
Vol 10 (03) ◽  
pp. 1750022 ◽  
Author(s):  
Mengying Xu ◽  
Zhidong Lin ◽  
Wenying Guo ◽  
Yuyuan Hong ◽  
Ping Fu ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Hydrothermal Process ◽  
Optimum Operating ◽  
Average Crystalline Size ◽  
Optimum Operating Temperature ◽  
Recovery Times ◽  
Response And Recovery ◽  
Simple Hydrothermal Process

Fe2(MoO4)3 nanoplates were prepared via a simple hydrothermal process. The average crystalline size of these nanoplates is 85.8[Formula: see text]nm. The sensor based on Fe2(MoO4)3 shows a high gas sensing performance to xylene. The response of Fe2(MoO4)3 sensor is 25.9–100[Formula: see text]ppm xylene at optimum operating temperature of 340[Formula: see text]C. The response and recovery times to 100[Formula: see text]ppm xylene are 4 and 10[Formula: see text]s, respectively. Furthermore, the Fe2(MoO4)3 sensor exhibits remarkable selectivity detection of xylene gas with negligible responses to toluene and benzene. Therefore, the Fe2(MoO4)3 is a promising material for the detection of xylene gas sensors.

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