scholarly journals Enhancement of functionalized carbon nanotubes gas sensor by adding metal oxide nanoparticles

2020 ◽  
Vol 18 (47) ◽  
pp. 62-72
Author(s):  
Sally K. Abbas ◽  
Asama Natik Naje
Keyword(s):  
Carbon Nanotubes ◽  
Response Time ◽  
Gas Sensor ◽  
Metal Oxide Nanoparticles ◽  
High Sensitivity ◽  
Complete Recovery ◽  
Single Wall Carbon Nanotubes ◽  
Sensitive Material ◽  
Multi Wall Carbon Nanotubes ◽  
Sensor Performance

Functionalized-multi wall carbon nanotubes (F-MWCNTs) and functionalized-single wall carbon nanotubes (F-SWCNTs) were well enhanced using CoO Nanoparticles. The sensor device consisted of a film of sensitive material (F-MWCNTs/CoONPs) and (F-SWCNTs/CoO NPs) deposited by drop- casting on an n-type porous silicon substrate. The two sensors perform high sensitivity to NO2 gas at room temperatures. The analysis indicated that the (F-MWCNTs/CoONPs) have a better performance than (F-SWCNTs/CoONPs). The F-SWCNTs/CoONPs gas sensor shows high sensitivity (19.1 %) at RT with response time 17 sec, while F-MWCNTs/CoONPs gas sensor show better sensitivity (39 %) at RT with response time 13 sec. The device shows a very reproducible sensor performance, with high repeatability, complete recovery, and adequate response. A demonstration of the improvement in sensing of NO2 gas using CoO-functionalized nanotubes is provided.

Room Temperature NO2 Gas Sensor Based on Functionalized Carbon Nanotubes /Nickel Oxide Nanoparticles

2020 ◽  
Vol 30 ◽  
pp. 1-7
Author(s):  
Sally K. Abbas ◽  
Asama N. Naje
Keyword(s):  
Carbon Nanotubes ◽  
Response Time ◽  
Nickel Oxide ◽  
Gas Sensor ◽  
High Sensitivity ◽  
Single Wall Carbon Nanotubes ◽  
Oxide Nanoparticles ◽  
Sensitive Material ◽  
Nickel Oxide Nanoparticles ◽  
Multi Wall Carbon Nanotubes

Functionalized-multi wall carbon nanotubes (F-MWCNTs) and functionalized-single wall carbon nanotubes (F-SWCNTs) were well enhanced using NiO Nanoparticles. The sensor device consisted of a film of sensitive material (F-MWCNTs/ Nickel oxide nanoparticles) and (F-SWCNTs/ Nickel oxide nanoparticles) deposited by drop casting on n-type porous silicon substrate. The two sensors perform high sensitivity to NO2 gas at particular temperatures. The analysis indicated that the (F-MWCNTs/NiONPs) have a better performance than (F-SWCNTs/NiONPs). The F-SWCNTs/NiONPs gas sensor shows high sensitivity (18.2 %) at RT with response time 16 sec, while F-MWCNTs/NiONPs gas sensor show better sensitivity (45 %) at RT with response time 26 sec. The device shows a very reproducible sensor performance, with high repeatability, complete recovery and adequate response. A demonstration of the improvement in sensing of NO2 gas using NiO-functionalized nanotubes is provided.

Transient Free Convective Flow of CNT Water Nanofluid with Heat Transfer from a Moving Cylinder

2020 ◽  
Vol 10 ◽  
Author(s):  
C. Sridevi ◽  
A. Sailakumari
Keyword(s):  
Carbon Nanotubes ◽  
Heat Generation ◽  
Convective Flow ◽  
Volume Fraction ◽  
Vertical Cylinder ◽  
Single Wall Carbon Nanotubes ◽  
Free Convective Flow ◽  
Multi Wall Carbon Nanotubes ◽  
Moving Cylinder ◽  
Variable Surface

Background: In this paper, transient two-dimensional laminar boundary layer viscous incompressible free convective flow of water based nanofluid with carbon nanotubes (CNTs) past a moving vertical cylinder with variable surface temperature is studied numerically in the presence of thermal radiation and heat generation. Methods: The prevailing partial differential equations which model the flow with initial and boundary conditions are solved by implicit finite difference method of Crank Nicolson type which is unconditionally stable and convergent. Results: Influence of Grashof number (Gr), nanoparticle volume fraction ( ), heat generation parameter (Q), temperature exponent (m), radiation parameter (N) and time (t) on velocity and temperature profiles are sketched graphically and elaborated comprehensively. Conclusion: Analysis of Nusselt number and Skin friction coefficient are also discussed numerically for both single wall carbon nanotubes (SWCNTs) and multi wall carbon nanotubes (MWCNTs).

Gas sensitive material on the basis of cholesteric-nematic mixture doped carbon nanotubes for optoelectronic NH3 gas sensor

2017 ◽  
Author(s):  
Vasyl S. Petryshak ◽  
Maria V. Vistak ◽  
Orest Y. Sushynkyi ◽  
Zinoviy M. Mikityuk ◽  
Hryhoriy I. Barylo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensor ◽  
Sensitive Material

Effect of Operating Temperature on Characteristics of Single-Walled Carbon Nanotubes Gas Sensor

2005 ◽  
Vol 486-487 ◽  
pp. 485-488 ◽  
Author(s):  
Hong Quang Nguyen ◽  
Mai Van Trinh ◽  
Jeung Soo Huh
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensor ◽  
Gas Adsorption ◽  
Operating Temperature ◽  
High Sensitivity ◽  
Single Walled Carbon Nanotubes ◽  
Fast Response ◽  
Carrier Gas ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

The effect of operating temperature on characteristics of single-walled carbon nanotubes (SWNT) based gas sensor was investigated. SWNT-based sensor was fabricated from SWNT powder (Iljin Nanotech, Korea) by screen-printing method. SWNT powder (30 mg, AP grade) was dispersed into 0.78 gram a-terpineol (Aldrich) by ultrasonic vibration for 1 hour then stirred manually for 1 hour to increase adhesion. From this condensed solution, a thick film of SWNT was printed onto alumina substrates. The film then was sintered at 300oC for 2 hours to remove residual impurities. Upon exposure to some gases such as nitrogen, ammonia or nitric oxide, resistance of the sensor dramatically changes due to gas adsorption. In our experiments, SWNT-based sensor was employed to detect NH3 gas in N2 ambience. After saturated of N2, the sensor exposes to NH3 with various concentrations (from 5 ppm to 100 ppm, diluted by N2 as carrier gas). This sensor exhibits a fast response, high sensitivity but slow recovery at room temperature. By heating at high temperature and increasing the flow-rate of carrier gas, NH3 gas desorbs easily and recovery of the sensor improved. The heating also influenced the characteristics of sensors such as response and reproducibility. Other special changes in electric property of SWNT-based sensor caused by heating are also discussed.

scholarly journals Application of Fractional Derivative Without Singular and Local Kernel to Enhanced Heat Transfer in CNTs Nanofluid Over an Inclined Plate

2020 ◽  
Author(s):  
Muhammad Saqib ◽  
Abdul Rahman Mohd Kasim ◽  
Nurul Farahain Mohammad ◽  
Dennis Ling Chuan Ching ◽  
Sharidan Shafie
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Fractional Derivatives ◽  
Saturated Porous Medium ◽  
Convection Heat Transfer ◽  
Heat Transfer Fluid ◽  
Single Wall Carbon Nanotubes ◽  
Inclined Plate ◽  
Multi Wall Carbon Nanotubes ◽  
Laplace Transform Technique

Nanofluids are a novel class of heat transfer fluid that plays a vital role in industries. In mathematical investigations, these fluids are modeled in terms of traditional integer-order partial differential equations (PDEs). It is recognized that traditional PDEs cannot decode the complex behavior of physical flow parameters and memory effects. Therefore, this article intends to study the mixed convection heat transfer in nanofluid over an inclined vertical plate via fractional derivatives approach. The problem in hand is modeled in connection with Atangana-Baleanu fractional derivatives without singular and local kernel having strong memory. The human blood is considered as base fluid dispersing carbon nanotube (CNTs) (single-wall carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes(MWCNTs )) into it to form blood-CNTs nanofluid. The nanofluids are considered to flow in a saturated porous medium under the influence of an applied magnetic field. The exact analytical expressions for velocity and temperature profiles are acquired using the Laplace transform technique and plotted in various graphs. The empirical results indicate that the memory effect decreases with increasing fractional parameters in the case of both temperature and velocity profiles. Moreover, the temperature profile is higher for blood-SWCNTs by reason of higher thermal conductivity whereas, this trend is opposite in case of velocity profile due densities difference.

scholarly journals A Stability Analysis of Solutions in Boundary Layer Flow and Heat Transfer of Carbon Nanotubes over a Moving Plate with Slip Effect

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3243 ◽  
Author(s):  
Nur Anuar ◽  
Norfifah Bachok ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Stability Analysis ◽  
Skin Friction ◽  
Single Wall Carbon Nanotubes ◽  
Slip Effect ◽  
Slip Parameter ◽  
Moving Plate ◽  
Multi Wall Carbon Nanotubes ◽  
Flow And Heat Transfer

The flow and heat transfer characteristics of both single-wall and multi-wall carbon nanotubes (CNTs) with water and kerosene as base fluid on a moving plate with slip effect are studied numerically. By employing similarity transformation, governing equations are transformed into a set of nonlinear ordinary equations. These equations are solved numerically using the bvp4c solver in Matlab which is a very efficient finite difference method. The influence of numerous parameters such as nanoparticle volume fraction, velocity ratio parameter and first order slip parameter on velocity, temperature, skin friction and heat transfer rate are further explored and discussed in the form of graphical and tabular forms. The results reveal that dual solutions exist when the plate and free stream move in the opposite direction and slip parameter was found to widen the range of the possible solutions. However, skin friction coefficients decrease, whereas the heat transfer increases in the presence of slip parameter. Single-wall carbon nanotubes (SWCNTs) give higher skin friction and heat transfer compared to multi-wall carbon nanotubes (MWCNTs) due to the fact that they have higher density and thermal conductivity. A stability analysis is carried out to determine the stability of the solutions obtained.

scholarly journals Application of Fractional Derivative Without Singular and Local Kernel to Enhanced Heat Transfer in CNTs Nanofluid Over an Inclined Plate

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 768 ◽  
Author(s):  
Muhammad Saqib ◽  
Abdul Rahman Mohd Kasim ◽  
Nurul Farahain Mohammad ◽  
Dennis Ling Chuan Ching ◽  
Sharidan Shafie
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Fractional Derivatives ◽  
Saturated Porous Medium ◽  
Convection Heat Transfer ◽  
Heat Transfer Fluid ◽  
Single Wall Carbon Nanotubes ◽  
Inclined Plate ◽  
Multi Wall Carbon Nanotubes ◽  
Laplace Transform Technique

Nanofluids are a novel class of heat transfer fluid that plays a vital role in industries. In mathematical investigations, these fluids are modeled in terms of traditional integer-order partial differential equations (PDEs). It is recognized that traditional PDEs cannot decode the complex behavior of physical flow parameters and memory effects. Therefore, this article intends to study the mixed convection heat transfer in nanofluid over an inclined vertical plate via fractional derivatives approach. The problem in hand is modeled in connection with Atangana–Baleanu fractional derivatives without singular and local kernel with a strong memory. Human blood is considered as base fluid and carbon nanotube (CNTs) (single-wall carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs)) are dispersed into it to form blood-CNTs nanofluid. The nanofluid is considered to flow in a saturated porous medium under the influence of an applied magnetic field. The exact analytical expressions for velocity and temperature profiles are acquired using the Laplace transform technique and plotted in various graphs. The empirical results indicate that the memory effect decreases with increasing fractional parameters in the case of both temperature and velocity profiles. Moreover, the temperature profile is higher for blood SWCNTs because of higher thermal conductivity whereas this trend is found opposite in the case of velocity profile due to densities difference.

scholarly journals Gas Sensing with Iridium Oxide Nanoparticle Decorated Carbon Nanotubes

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 113 ◽  
Author(s):  
Juan Casanova-Cháfer ◽  
Eric Navarrete ◽  
Xavier Noirfalise ◽  
Polona Umek ◽  
Carla Bittencourt ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensing ◽  
Metal Oxide Nanoparticles ◽  
Iridium Oxide ◽  
Oxide Nanoparticles ◽  
Step Method ◽  
Experimental Conditions ◽  
Multi Wall Carbon Nanotubes ◽  
Condensation Growth ◽  
Oxide Nanoparticle

The properties of multi-wall carbon nanotubes decorated with iridium oxide nanoparticles (IrOx-MWCNTs) are studied to detect harmful gases such as nitrogen dioxide and ammonia. IrOx nanoparticles were synthetized using a two-step method, based on a hydrolysis and acid condensation growth mechanism. The metal oxide nanoparticles obtained were employed for decorating the sidewalls of carbon nanotubes. Iridium-oxide nanoparticle decorated carbon nanotube material showed higher and more stable responses towards NH3 and NO2 than bare carbon nanotubes under different experimental conditions, establishing the optimal operating temperatures and estimating the limits of detection and quantification. Furthermore, the nanomaterials employed were studied using different morphological and compositional characterization techniques and a gas sensing mechanism is proposed.

MORPHOLOGY EFFECT OF Ni–Ag/CARBON NANOMATERIALS ON THEIR ELECTROCATALYTIC ACTIVITY FOR GLUCOSE OXIDATION

2016 ◽  
Vol 23 (06) ◽  
pp. 1650059 ◽  
Author(s):  
RUIZHUO OUYANG ◽  
WEIWEI LI ◽  
YANG YANG ◽  
WANGYAO ZHANG ◽  
KAI FENG ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Morphology ◽  
Active Sites ◽  
Carbon Nanomaterials ◽  
Modified Electrodes ◽  
Single Wall Carbon Nanotubes ◽  
Composite Electrodes ◽  
Ag Nps ◽  
Multi Wall Carbon Nanotubes ◽  
Ag Deposition

We presented here three carbon-nanomaterials-based modified glassy carbon electrodes (GCE) with Ni–Ag nanohybrid nanoparticles (NPs) deposited upon, including single-wall carbon nanotubes (SWCNTs), multi-wall carbon nanotubes (MWCNTs) and the mesoporous carbons (MPCs), and compared their morphology effects on both Ni–Ag deposition quality and electrocatalytic performances toward Glu oxidation. After being deposited with Ni–Ag NPs, a homogenous surface with very small Ni–Ag NPs was obtained for Ni–Ag/SWCNTs/GCE, while heterogeneous, coarse surfaces with obvious embedment with large Ni–Ag particles were observed for both Ni–Ag/MWCNTs/GCE and Ni–Ag/MPC/GCE. All three modified electrodes were well characterized in terms of surface morphology, electron transfer rate, hydrophilicity, interference resistance, stability, electrocatalytic behaviors as well as practicability in real samples, based on which Ni–Ag/SWCNTs/GCE was always proved to be more advantageous over other two composite electrodes. Such advantage of Ni–Ag/SWCNTs/GCE was attributed to its desirable surface morphology good for Ni–Ag deposition and exposure of as many active sites as possible to Glu oxidation, leading to the extraordinary electrocatalytic performance.

Sign in / Sign up

Export Citation Format

Share Document