scholarly journals Synthesis of a Flower-Like g-C3N4/ZnO Hierarchical Structure with Improved CH4 Sensing Properties

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 724 ◽  
Author(s):  
Xiaojie Li ◽  
Yanwei Li ◽  
Guang Sun ◽  
Na Luo ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Hierarchical Structure ◽  
Carbon Nitride ◽  
Fast Response ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Sensing Properties ◽  
Long Term Stability ◽  
Response Recovery ◽  
Calcination Method

In this paper, a hierarchical structure of graphite carbon nitride (g-C3N4) modified ZnO (g-C3N4/ZnO) was synthesized using a simple precipitation-calcination method. Through this method, g-C3N4 nanosheets with a controlled content were successfully decorated on the petals of flower-like ZnO. Various techniques were used to confirm the successful formation of the g-C3N4/ZnO hierarchical structure. The methane (CH4) sensing properties of g-C3N4/ZnO sensor were investigated. The result exhibited that after decorating ZnO with g-C3N4, the CH4 sensing performances of the fabricated sensor were remarkably improved. At the optimum operating temperature of 320 °C, the response of the sensor fabricated with CNZ-3 (the sample with an optimum content of g-C3N4) towards 1000 ppm CH4 was as high as 11.9 (Ra/Rg), which was about 2.2 times higher than that of the pure ZnO sensor (5.3). In addition, the CNZ-3 sensor also exhibited a fast response/recovery speed (15/28 s) and outstanding long-term stability. The enhancing CH4 sensing mechanism may be contributed to enlarged surface area, pore structure, and g-C3N4-ZnO n-n junction.

scholarly journals Enhanced Methane Sensing Properties of WO3 Nanosheets with Dominant Exposed (200) Facet via Loading of SnO2 Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 351 ◽  
Author(s):  
Dongping Xue ◽  
Junjun Wang ◽  
Yan Wang ◽  
Guang Sun ◽  
Jianliang Cao ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Defect Density ◽  
Sno2 Nanoparticles ◽  
High Reactivity ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Sensing Properties ◽  
Long Term Stability ◽  
Subsequent Calcination

Methane detection is extremely difficult, especially at low temperatures, due to its high chemical stability. Here, WO3 nanosheets loaded with SnO2 nanoparticles with a particle size of about 2 nm were prepared by simple impregnation and subsequent calcination using SnO2 and WO3·H2O as precursors. The response of SnO2-loaded WO3 nanosheet composites to methane is about 1.4 times higher than that of pure WO3 at the low optimum operating temperature (90 °C). Satisfying repeatability and long-term stability are ensured. The dominant exposed (200) crystal plane of WO3 nanosheets has a good balance between easy oxygen chemisorption and high reactivity at the dangling bonds of W atoms, beneficial for gas-sensing properties. Moreover, the formation of a n–n type heterojunction at the SnO2-WO3 interface and additionally the increase of specific surface area and defect density via SnO2 loading enhance the response further. Therefore, the SnO2-WO3 composite is promising for the development of sensor devices to methane.

Electrical and Humidity-Sensing Properties of EuCl2, Eu2O3 and EuCl2/Eu2O3 Blend Films

Chemosensors ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 288
Author(s):  
Pi-Guey Su ◽  
Nok-Him Choy
Keyword(s):  
Complex Impedance ◽  
Fast Response ◽  
Humidity Sensing ◽  
Sensing Properties ◽  
Blend Film ◽  
Blend Films ◽  
Long Term Stability ◽  
Humidity Sensing Properties

Impedance-type humidity sensors based on EuCl2, Eu2O3 and EuCl2/Eu2O3 blend films were fabricated. The electrical properties of the pure EuCl2 and Eu2O3 films and EuCl2/Eu2O3 blend film that was blended with different amounts of EuCl2 were investigated as functions of relative humidity. The influences of the EuCl2 to the humidity-sensing properties (sensitivity and linearity) of the EuCl2/Eu2O3 blend film were thus elucidated. The impedance-type humidity sensor that was made of a 7 wt% EuCl2/Eu2O3 blend film exhibited the highest sensitivity, best linearity, a small hysteresis, a fast response time, a small temperature coefficient and long-term stability. The complex impedance plots were used to elucidate the role of ions in the humidity-sensing behavior of the EuCl2/Eu2O3 blend film.

High-performance humidity sensors from Ni(SO4)0.3(OH)1.4 nanobelts

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 6521-6525 ◽  
Author(s):  
Ming Zhuo ◽  
Yuejiao Chen ◽  
Tao Fu ◽  
Haonan Zhang ◽  
Zhi Xu ◽  
...  
Keyword(s):  
High Performance ◽  
Humidity Sensor ◽  
High Sensitivity ◽  
Fast Response ◽  
Humidity Sensors ◽  
Term Stability ◽  
Long Term Stability

Ni(SO4)0.3(OH)1.4 nanobelts are utilized in a humidity sensor by a facile method. The nanobelt based sensor shows a high sensitivity, fast response and long-term stability in the sensing process.

3D ordered porous SnO2 with a controllable pore diameter for enhanced formaldehyde sensing performance

2020 ◽  
Vol 13 (07) ◽  
pp. 2051044
Author(s):  
Dan Sun ◽  
Huixiao Guo ◽  
Yu Li ◽  
Haiying Li ◽  
Xiaosong Li ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Porous Structures ◽  
Gas Sensitivity ◽  
Long Term Stability ◽  
Response Recovery ◽  
Recovery Times ◽  
Formaldehyde Sensing ◽  
Different Diameters ◽  
Ordered Porous

This paper reports the preparation of 3D ordered porous SnO2 with different diameters (103, 546, and 1030[Formula: see text]nm) by a simple template method. We find that 103[Formula: see text]nm porous SnO2 nanomaterials have the highest response (30) and fastest response/recovery time (3/10 s) for 100 ppm HCHO (formaldehyde) compared with the response and response/recovery times for 546 nm (20 and 3/17[Formula: see text]s, respectively) and 1030 nm (10 and 6/20[Formula: see text]s, respectively) porous SnO2 nanomaterials at a low working temperature (220∘C). All three sensors show good long-term stability, repeatability, and linearity. The results show that decreasing the diameter of the porous SnO2 materials effectively increased the gas sensitivity to HCHO. The increase in the gas sensitivity was attributed to the ordered porous structures, large specific surface area, and additional oxygen vacancies on the surface.

TUNGSTEN-DOPED TiO2 NANOLAYERS WITH IMPROVED CO2 GAS SENSING PROPERTIES FOR ENVIRONMENTAL APPLICATIONS

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850024 ◽  
Author(s):  
MALIHEH SABERI ◽  
ALI AKBAR ASHKARRAN
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Sol Gel ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Sensing Properties ◽  
Vis Spectroscopy ◽  
Gas Sensing Properties ◽  
Tungsten Concentration

Tungsten-doped TiO2 gas sensors were successfully synthesized using sol–gel process and spin coating technique. The fabricated sensor was characterized by field emission scanning electron microscopy (FE-SEM), ultraviolet visible (UV–Vis) spectroscopy, transmission electron microscopy (TEM), X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Gas sensing properties of pristine and tungsten-doped TiO2 nanolayers (NLs) were probed by detection of CO2 gas. A series of experiments were conducted in order to find the optimum operating temperature of the prepared sensors and also the optimum value of tungsten concentration in TiO2 matrix. It was found that introducing tungsten into the TiO2 matrix enhanced the gas sensing performance. The maximum response was found to be (1.37) for 0.001[Formula: see text]g tungsten-doped TiO2 NLs at 200[Formula: see text]C as an optimum operating temperature.

Graphene oxide in carbon nitride: from easily processed precursors to a composite material with enhanced photoelectrochemical activity and long-term stability

2019 ◽  
Vol 7 (19) ◽  
pp. 11718-11723 ◽  
Author(s):  
Guiming Peng ◽  
Jiani Qin ◽  
Michael Volokh ◽  
Chong Liu ◽  
Menny Shalom
Keyword(s):  
Composite Material ◽  
Graphene Oxide ◽  
Charge Separation ◽  
Carbon Nitride ◽  
Photoelectrochemical Activity ◽  
Term Stability ◽  
Long Term Stability ◽  
Transfer Properties

Herein we report a facile method to grow an ordered carbon nitride (CN) layer with improved charge separation and transfer properties under illumination.

High performance electrochromic devices based on a polyindole derivative, poly(1H-benzo[g]indole)

2015 ◽  
Vol 3 (43) ◽  
pp. 11318-11325 ◽  
Author(s):  
Guangming Nie ◽  
Ling Wang ◽  
Changlong Liu
Keyword(s):  
Response Time ◽  
High Performance ◽  
Optical Memory ◽  
Fast Response ◽  
Electrochromic Devices ◽  
Optical Contrast ◽  
Fast Response Time ◽  
Coloration Efficiency ◽  
Long Term Stability

An ECD based on electrochromic poly(1H-benzo[g]indole) was fabricated. The color of this ECD can switch between green and navy blue with good optical contrast, high coloration efficiency, fast response time, better optical memory and long-term stability.

scholarly journals Self-Healable Organic Electrochemical Transistor with High Transconductance, Fast Response, and Long-Term Stability

2020 ◽  
Vol 12 (30) ◽  
pp. 33979-33988
Author(s):  
Jieun Ko ◽  
Xihu Wu ◽  
Abhijith Surendran ◽  
Bening Tirta Muhammad ◽  
Wei Lin Leong
Keyword(s):  
Fast Response ◽  
Term Stability ◽  
Long Term Stability ◽  
Electrochemical Transistor ◽  
High Transconductance

scholarly journals Sensing Properties of Oxidized Nanostructured Silicon Surface on Vaporized Molecules

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 119 ◽  
Author(s):  
Nikola Baran ◽  
Hrvoje Gebavi ◽  
Lara Mikac ◽  
Davor Ristić ◽  
Marijan Gotić ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Electrochemical Etching ◽  
Ammonia Gas ◽  
Sensing Properties ◽  
Long Term Stability ◽  
The Past ◽  
Oxygen Treatment ◽  
Ambient Concentration ◽  
Potential Use

Porous silicon has been intensely studied for the past several decades and its applications were found in photovoltaics, biomedicine, and sensors. An important aspect for sensing devices is their long–term stability. One of the more prominent changes that occur with porous silicon as it is exposed to atmosphere is oxidation. In this work we study the influence of oxidation on the sensing properties of porous silicon. Porous silicon layers were prepared by electrochemical etching and oxidized in a tube furnace. We observed that electrical resistance of oxidized samples rises in response to the increasing ambient concentration of organic vapours and ammonia gas. Furthermore, we note the sensitivity is dependent on the oxygen treatment of the porous layer. This indicates that porous silicon has a potential use in sensing of organic vapours and ammonia gas when covered with an oxide layer.

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