Fabrication of a Carbon Nanotube Gas Sensor Microelectrodes and its Application for Ammonia Detection

2013 ◽  
Vol 431 ◽  
pp. 306-311
Author(s):  
Xiang Tao Ran ◽  
Zhi Wang ◽  
Li Yang

With the increasing needs for high-performance gas sensors in industrial production, environmental monitoring and so on, the research on gas sensors is becoming more and more important. In this paper, the electric field intensity distribution simulation process of the interdigital microelectrodes (IMEs) is discussed in details to get the proper electrode structural parameters. The IMEs on the ITO surface with a minimum gap of about 4μm are achieved by lithography, which provides a reliable, low-cost manufacturing method. Sensitive components are made of the multi-walled carbon nanotubes modified materials. The gas-sensing property of the sensor is detected for ammonia. The experiment result shows that the performance of the nanomodified sensor is obviously improved.

Author(s):  
Yaofeng Wang ◽  
Fan Wang ◽  
Yang Kong ◽  
Lei Wang ◽  
Qinchuan Li

Abstract High-performance bioartificial muscles with low-cost, large bending deformation, low actuation voltage, and fast response time have drawn extensive attention as the development of human-friendly electronics in recent years. Here, we report a high-performance ionic bioartificial muscle based on the bacterial cellulose (BC)/ionic liquid (IL)/multi-walled carbon nanotubes (MWCNT) nanocomposite membrane and PEDOT:PSS electrode. The developed ionic actuator exhibits excellent electro-chemo-mechanical properties, which are ascribed to its high ionic conductivity, large specific capacitance, and ionically crosslinked structure resulting from the strong ionic interaction and physical crosslinking among BC, IL, and MWCNT. In particular, the proposed BC-IL-MWCNT (0.10 wt%) nanocomposite exhibited significant increments of Young's modulus up to 75% and specific capacitance up to 77%, leading to 2.5 times larger bending deformation than that of the BC-IL actuator. More interestingly, bioinspired applications containing artificial soft robotic finger and grapple robot were successfully demonstrated based on high-performance BC-IL-MWCNT actuator with excellent sensitivity and controllability. Thus, the newly proposed BC-IL-MWCNT bioartificial muscle will offer a viable pathway for developing next-generation artificial muscles, soft robotics, wearable electronic products, flexible tactile devices, and biomedical instruments.


2020 ◽  
Vol 44 (7-8) ◽  
pp. 487-493
Author(s):  
Hong-Yan Lin ◽  
Yi-Fei Wang ◽  
Yuan Tian ◽  
Guo-Cheng Liu ◽  
Jian Luan

A CuI coordination polymer based on the N,N’-bis(3-pyridinecarboxamide)-1,4-butane (3-dpyb) ligand, namely [Cu(3-dpyb)0.5Cl], is hydrothermally synthesized and structurally characterized, and is used as a catalyst precursor to synthesize multi-walled carbon nanotubes. Interestingly, the as-grown multi-walled carbon nanotubes exhibit high performance in removing dyes from solution and can serve as a low-cost and fast adsorbent. In addition, the adsorption behavior of this new adsorbent fits well with the Freundlich isotherm and the pseudo-second-order kinetic model.


2020 ◽  
Vol 8 (26) ◽  
pp. 13095-13105 ◽  
Author(s):  
Qiujun Hu ◽  
Zhongxu Lu ◽  
Yizhuo Wang ◽  
Jing Wang ◽  
Hong Wang ◽  
...  

Multi-walled carbon nanotubes (MWCNTs) have shown low n-type Seebeck coefficients (−10 μV K−1), which are not good enough to prepare high performance low-cost MWCNT based mechanically flexible thermoelectric devices.


2019 ◽  
Vol 7 (5) ◽  
pp. 404-417 ◽  
Author(s):  
Fatemeh Ganjeizadeh Rohani ◽  
Mehdi Ansari

Background: Multi-walled carbon nanotubes (MWCNT) adjunct to molecularly imprinted polymers (MIP) have advantages of the large surface area of nanoparticles and selectivity of MIPs for selective extraction of tetradifon as a widely used pesticide in date palm. Objectives: The main aims were the use of experimental design, electrochemical synthesis and ultra-high performance liquid chromatography (UHPLC) to develop a simple, reliable and precise pesticide residue analysis method as an important aspect of food and drug quality control for the determination of tetradifon in date palms. Methods: An MIP in the presence of MWCNT was synthesized by cyclic voltammetric technique on a steel rod to produce a composite of MIP-MWCNTs for stir bar extraction of tetradifon residue in date samples. The experimental design was used to optimize MIPMWCNT composite synthesis through the screening of eight variables. The composite was characterized by scanning electron microscopy (SEM). Tetradifon was determined in extracted samples by UHPLC under optimum conditions. Results: A very thin film was made by MIP-MWCNT coated on a steel rod which was repeatable and had good adhesion and persistence. The detection limit (LOD) and the quantification limit (LOQ) of the method were measured as 16 and 49 ng/ml, respectively. Average recovery of tetradifon at the two spiked levels was observed to be as low as 86.5% to 90.7% (RSD from 0.79% to 1.04%). Conclusion: The low cost, high selectivity, good reproducibility, acceptable intra and inter day precision and accuracy developed method were successfully applied to determine tetradifon residue in date samples purchased from a local market.


2015 ◽  
Vol 3 (41) ◽  
pp. 20690-20697 ◽  
Author(s):  
Huaping Chen ◽  
Yufei Zhang ◽  
Jun Yang ◽  
Ziyang Dai ◽  
Nina Fu ◽  
...  

A template-free two-step strategy is successfully developed for the low-cost one pot production of Ni0.33Co0.66(OH)F hollow hexagons woven by multi-walled carbon nanotubes (MWCNTs).


2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Jingyao Liu ◽  
Zhixiang Hu ◽  
Yuzhu Zhang ◽  
Hua-Yao Li ◽  
Naibo Gao ◽  
...  

AbstractThe Internet of things for environment monitoring requires high performance with low power-consumption gas sensors which could be easily integrated into large-scale sensor network. While semiconductor gas sensors have many advantages such as excellent sensitivity and low cost, their application is limited by their high operating temperature. Two-dimensional (2D) layered materials, typically molybdenum disulfide (MoS2) nanosheets, are emerging as promising gas-sensing materials candidates owing to their abundant edge sites and high in-plane carrier mobility. This work aims to overcome the sluggish and weak response as well as incomplete recovery of MoS2 gas sensors at room temperature by sensitizing MoS2 nanosheets with PbS quantum dots (QDs). The huge amount of surface dangling bonds of QDs enables them to be ideal receptors for gas molecules. The sensitized MoS2 gas sensor exhibited fast and recoverable response when operated at room temperature, and the limit of NO2 detection was estimated to be 94 ppb. The strategy of sensitizing 2D nanosheets with sensitive QD receptors may enhance receptor and transducer functions as well as the utility factor that determine the sensor performance, offering a powerful new degree of freedom to the surface and interface engineering of semiconductor gas sensors.


2021 ◽  
Vol 6 (1) ◽  
pp. 14
Author(s):  
Shirong Huang ◽  
Luis Antonio Panes-Ruiz ◽  
Alexander Croy ◽  
Leif Riemenschneider ◽  
Vyacheslav Khavrus ◽  
...  

Recently, graphene has attracted intensive attention in the gas sensing field due to its high electrical conductivity as well as large specific surface areas. Lots of graphene-based gas sensors have been reported with excellent gas sensing performance. However, the sensing element materials for most of the above sensors actually consist of a reduced graphene oxide (rGO) derivative rather than pristine graphene, such as rGO, rGO/metal particle, rGO/polymers, etc. Complex chemical oxidation and reduction are usually involved for the preparation of reduced graphene oxide derivatives. Even though there are some pristine graphene-based gas sensors synthesizing with the approaches of chemical vapor deposition (CVD) or mechanical cleavage, the high cost of the set-up or the low productivity cannot decrease the cost of the practical sensors. In this work, we develop pristine graphene-based gas sensors utilizing flavin monocleotide sodium salt (FMNS) toward ultra-sensitive ammonia detection. The sensor has 3% response upon exposure to 10 ppm NH3 and a limit of detection of 1.6 ppm at room temperature and shows a good recovery. Raman, UV–Vis, FT-IR spectra, as well as scanning electron microscope (SEM) measurements are employed to characterize the quality of the graphene flakes, indicating a good structural quality of graphene with few defects. The effects of the concentration of graphene dispersion functionalized by FMNS on the sensing performance towards ammonia sensing were also investigated. The process is very mild, environmentally friendly, and low cost. We believe this work may pave a path to design a high-performance gas sensor with low cost and boost the application of graphene for sensing.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 783 ◽  
Author(s):  
Andrea Gaiardo ◽  
David Novel ◽  
Elia Scattolo ◽  
Michele Crivellari ◽  
Antonino Picciotto ◽  
...  

The substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane sizes were developed using the microfabrication process. The performance of these devices was evaluated to predict their thermal and mechanical behaviors by using both experimental and theoretical approaches. Finally, a statistical method was employed to cross-correlate the thermal predictive model and the mechanical failure analysis, aiming at microheater design optimization for gas-sensing applications.


Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3947
Author(s):  
Wei Wang ◽  
Qinyi Zhang ◽  
Ruonan Lv ◽  
Dong Wu ◽  
Shunping Zhang

High performance formaldehyde gas sensors are widely needed for indoor air quality monitoring. A modified layer of zeolite on the surface of metal oxide semiconductors results in selectivity improvement to formaldehyde as gas sensors. However, there is insufficient knowledge on how the thickness of the zeolite layer affects the gas sensing properties. In this paper, ZSM-5 zeolite films were coated on the surface of the SnO2 gas sensors by the screen printing method. The thickness of ZSM-5 zeolite films was controlled by adjusting the numbers of screen printing layers. The influence of ZSM-5 film thickness on the performance of ZSM-5/SnO2 gas sensors was studied. The results showed that the ZSM-5/SnO2 gas sensors with a thickness of 19.5 μm greatly improved the selectivity to formaldehyde, and reduced the response to ethanol, acetone and benzene at 350 °C. The mechanism of the selectivity improvement to formaldehyde of the sensors was discussed.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 372
Author(s):  
Liyang Lin ◽  
Susu Chen ◽  
Tao Deng ◽  
Wen Zeng

The metal oxides/graphene nanocomposites have great application prospects in the fields of electrochemical energy storage and gas sensing detection. However, rational synthesis of such materials with good conductivity and electrochemical activity is the topical challenge for high-performance devices. Here, SnO2/graphene nanocomposite is taken as a typical example and develops a universal synthesis method that overcome these challenges and prepares the oxygen-deficient SnO2 hollow nanospheres/graphene (r-SnO2/GN) nanocomposite with excellent performance for supercapacitors and gas sensors. The electrode r-SnO2/GN exhibits specific capacitance of 947.4 F g−1 at a current density of 2 mA cm−2 and of 640.0 F g−1 even at 20 mA cm−2, showing remarkable rate capability. For gas-sensing application, the sensor r-SnO2/GN showed good sensitivity (~13.8 under 500 ppm) and short response/recovering time toward methane gas. These performance features make r-SnO2/GN nanocomposite a promising candidate for high-performance energy storage devices and gas sensors.


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