Research on the Gas Sensing Enhancement by Using CNT/ZnO Composites

2013 ◽  
Vol 562-565 ◽  
pp. 1522-1526
Author(s):  
Ling Min Yu ◽  
Xin Hui Fan ◽  
Jing Yi Shui ◽  
Li Jun Qi ◽  
Wen Yan
Keyword(s):  
Gas Sensing ◽  
Multiwall Carbon Nanotubes ◽  
Weight Ratio ◽  
Fast Response ◽  
Zno Nanowires ◽  
Zno Films ◽  
Response Recovery ◽  
Hybrid Sensors ◽  
Multiwall Carbon ◽  
Higher Sensitivity

Multiwall carbon nanotubes (CNT) were added into ZnO matrix to develop a CNTs/ZnO composite gas sensor. The hybrid sensor is used to detect CO in air by measuring resistance changes of thin CNTs/ZnO films at different working temperature. For comparison, pure ZnO and CNT/ZnO sensors are also examined. The gas sensing results reveal that CNTs/ZnO with the weight ratio (9:100) hybrid sensors exhibit much higher sensitivity and fast response-recovery properties towards CO, at 240°C than the blank ZnO nanowires. Hybrid material of ZnO nanowires and CNT composites could potentially display not only the unique properties of nanowires and those of CNTs, but also an additional novel property.

Gold functionalized ZnO nanowires as a fast response/recovery ammonia sensor

2018 ◽  
Vol 449 ◽  
pp. 244-249 ◽  
Author(s):  
Nancy Anna Anasthasiya A. ◽  
Roopa Kishore Kampara ◽  
Rai P.K. ◽  
Jeyaprakash B.G.
Keyword(s):  
Fast Response ◽  
Zno Nanowires ◽  
Ammonia Sensor ◽  
Response Recovery

scholarly journals Nanostructured ZnO/Ag Film Prepared by Magnetron Sputtering Method for Fast Response of Ammonia Gas Detection

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1899 ◽  
Author(s):  
Yiran Zheng ◽  
Min Li ◽  
Xiaoyan Wen ◽  
Ho-Pui Ho ◽  
Haifei Lu
Keyword(s):  
Magnetron Sputtering ◽  
Thermal Annealing ◽  
Physical Vapor Deposition ◽  
Gas Sensing ◽  
Volume Ratio ◽  
Fast Response ◽  
Gas Detection ◽  
Zno Films ◽  
Zno Film ◽  
Ammonia Gas

Possessing a large surface-to-volume ratio is significant to the sensitive gas detection of semiconductor nanostructures. Here, we propose a fast-response ammonia gas sensor based on porous nanostructured zinc oxide (ZnO) film, which is fabricated through physical vapor deposition and subsequent thermal annealing. In general, an extremely thin silver (Ag) layer (1, 3, 5 nm) and a 100 nm ZnO film are sequentially deposited on the SiO2/Si substrate by a magnetron sputtering method. The porous nanostructure of ZnO film is formed after thermal annealing contributed by the diffusion of Ag among ZnO crystal grains and the expansion of the ZnO film. Different thicknesses of the Ag layer help the formation of different sizes and quantities of hollows uniformly distributed in the ZnO film, which is demonstrated to hold superior gas sensing abilities than the compact ZnO film. The responses of the different porous ZnO films were also investigated in the ammonia concentration range of 10 to 300 ppm. Experimental results demonstrate that the ZnO/Ag(3 nm) sensor possesses a good electrical resistance variation of 85.74% after exposing the sample to 300 ppm ammonia gas for 310 s. Interestingly, a fast response of 61.18% in 60 s for 300 ppm ammonia gas has been achieved from the ZnO/Ag(5 nm) sensor, which costs only 6 s for the response increase to 10%. Therefore, this controllable, porous, nanostructured ZnO film maintaining a sensitive gas response, fabricated by the physical deposition approach, will be of great interest to the gas-sensing community.

Experimental Investigation of Mechanical Behavior of Carbon-Nanotube Reinforced Cement Mortar

2011 ◽  
Vol 142 ◽  
pp. 217-220
Author(s):  
Li Wu Chang ◽  
Jin Chao Yue ◽  
Yu Zhou Sun
Keyword(s):  
Carbon Nanotube ◽  
Cement Mortar ◽  
Multiwall Carbon Nanotubes ◽  
Weight Ratio ◽  
Ultrasonic Energy ◽  
Reinforced Composites ◽  
Effective Dispersion ◽  
Optimum Weight ◽  
Reinforced Cement ◽  
Multiwall Carbon

In this study, effective dispersion of different amount of multiwall carbon nanotubes was achieved using a surfactant and in combination with the use of ultrasonic energy. The effects of surfactant and surfactant concentration on the plain cement mortar were investigated. Moreover, the mechanical behaviors of the carbon-nanotube reinforced composites were also analyzed. Experimental results indicate that the application of ultrasonic energy is absolutely necessary to produce a satisfactory dispersion of MWCNTs, and there exists an optimum weight ratio of surfactant to MWCNTs. It is found that the proper dispersion of MWCNTs can remarkably improve the flexural strength, compressive strength, and the toughness of the cement mortar composites.

scholarly journals Gas sensing properties of multiwall carbon nanotubes decorated with rhodium nanoparticles

2011 ◽  
Vol 160 (1) ◽  
pp. 974-980 ◽  
Author(s):  
R. Leghrib ◽  
T. Dufour ◽  
F. Demoisson ◽  
N. Claessens ◽  
F. Reniers ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensing ◽  
Multiwall Carbon Nanotubes ◽  
Sensing Properties ◽  
Rhodium Nanoparticles ◽  
Gas Sensing Properties ◽  
Multiwall Carbon

scholarly journals Gas Sensors Based on Chemi-Resistive Hybrid Functional Nanomaterials

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingying Jian ◽  
Wenwen Hu ◽  
Zhenhuan Zhao ◽  
Pengfei Cheng ◽  
Hossam Haick ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Carrier Transport ◽  
Gas Sensing ◽  
Low Cost ◽  
Functional Materials ◽  
Fast Response ◽  
Hybrid Functional ◽  
Great Stability ◽  
Molecular Binding ◽  
Response Recovery

AbstractChemi-resistive sensors based on hybrid functional materials are promising candidates for gas sensing with high responsivity, good selectivity, fast response/recovery, great stability/repeatability, room-working temperature, low cost, and easy-to-fabricate, for versatile applications. This progress report reviews the advantages and advances of these sensing structures compared with the single constituent, according to five main sensing forms: manipulating/constructing heterojunctions, catalytic reaction, charge transfer, charge carrier transport, molecular binding/sieving, and their combinations. Promises and challenges of the advances of each form are presented and discussed. Critical thinking and ideas regarding the orientation of the development of hybrid material-based gas sensor in the future are discussed.

Kinetic Modeling of Carbon Nanotube Production and Minimization of Amorphous Carbon Overlayer Deposition in Floating Catalyst Method

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Leila Samandari-Masouleh ◽  
Navid Mostoufi ◽  
AA Khodadadi ◽  
Y. Mortazavi ◽  
Morteza Maghrebi
Keyword(s):  
Carbon Nanotubes ◽  
Amorphous Carbon ◽  
Kinetic Modeling ◽  
Carbon Deposition ◽  
Multiwall Carbon Nanotubes ◽  
Weight Ratio ◽  
Carbon Formation ◽  
Reactor Kinetic ◽  
Bottom To Top ◽  
Multiwall Carbon

Abstract A kinetic modeling of longitudinal and depth profiles of multiwall carbon nanotubes (MWCNTs) synthesis using xylene and ferrocene in a floating catalyst (FC) reactor is hereby reported. Both amorphous and arrays of carbon nanotubes (CNTs) are formed, whose ratio sharply increases along a growth window and from the bottom to top of the arrays. A model is presented for the rate of CNTs synthesis as well as the rate of amorphous carbon formation which undesirably forms on the nanotube walls and reduces nanotubes quality and synthesis efficiency. Based on the amounts of amorphous carbons and CNTs formed in the reactor, kinetic parameters of formation of these species from xylene were estimated. It is shown that, as the temperature increases, the weight ratio of amorphous carbon to CNTs shows minimum at 970 K. The ratio increases with decreasing the amount of deposited iron. Increasing pressure and carrier gas is found to have marginal effects on producing CNTs with lower amounts of amorphous carbon. Higher surface density of CNTs (number of CNTs per surface area) and their diameter, result in a significantly higher amount of amorphous carbon deposition.

scholarly journals CTAB-Assisted Hydrothermal Synthesis of WO3Hierarchical Porous Structures and Investigation of Their Sensing Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Dan Meng ◽  
Guosheng Wang ◽  
Xiaoguang San ◽  
Yanbai Shen ◽  
Guodong Zhao ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Nitrogen Adsorption ◽  
Fast Response ◽  
Photoelectron Spectra ◽  
Porous Structures ◽  
X Ray ◽  
Transmission Electron ◽  
Hierarchical Porous ◽  
Adsorption Desorption ◽  
Higher Sensitivity

WO3hierarchical porous structures were successfully synthesized via cetyltrimethylammonium bromide- (CTAB-) assisted hydrothermal method. The structure and morphology were investigated using scanning electron microscope, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectra, Brunauer-Emmett-Teller nitrogen adsorption-desorption, and thermogravimetry and differential thermal analysis. The result demonstrated that WO3hierarchical porous structures with an orthorhombic structure were constructed by a number of nanoparticles about 50–100 nm in diameters. The H2gas sensing measurements showed that well-defined WO3hierarchical porous structures with a large specific surface area exhibited the higher sensitivity compared with products without CTAB at all operating temperatures. Moreover, the reversible and fast response to H2gas and good selectivity were obtained. The results indicated that the WO3hierarchical porous structures are promising materials for gas sensors.

Solvothermal synthesis of ZnO-decorated α-Fe2O3 nanorods with highly enhanced gas-sensing performance toward n-butanol

2014 ◽  
Vol 2 (33) ◽  
pp. 13283-13292 ◽  
Author(s):  
Yusuf V. Kaneti ◽  
Quadir M. D. Zakaria ◽  
Zhengjie Zhang ◽  
Chuyang Chen ◽  
Jeffrey Yue ◽  
...  
Keyword(s):  
Solvothermal Synthesis ◽  
Gas Sensing ◽  
Solvothermal Method ◽  
Fast Response ◽  
Working Temperature ◽  
Enhanced Sensitivity ◽  
Response Recovery ◽  
Facile Solvothermal Method ◽  
Sensing Performance

A facile solvothermal method has been developed for the synthesis of α-Fe2O3/ZnO nanocomposites that show enhanced sensitivity, selectivity and fast response–recovery toward n-butanol at a working temperature of 225 °C.

Y-doped In2O3 hollow nanocubes for improved triethylamine-sensing performance

2021 ◽  
Vol 45 (15) ◽  
pp. 6773-6779
Author(s):  
Qi Zhao ◽  
Guoce Zhuang ◽  
Yongbing Zhao ◽  
Liangliang Yang ◽  
Jinshan Zhao
Keyword(s):  
Gas Sensing ◽  
Fast Response ◽  
High Response ◽  
Sensing Properties ◽  
Response Recovery ◽  
Gas Sensing Properties ◽  
Sensing Performance

Y-In2O3 hollow nanocubes show enhanced triethylamine gas sensing properties, with a high response and an ultra-fast response-recovery speed.

Hierarchical Flower-Like Microspheres: An Application of Hydrogen Sulfide Gas Sensor for Tunnel Construction

2021 ◽  
Vol 16 (1) ◽  
pp. 1-5
Author(s):  
Chuansheng Wu ◽  
Yuyue Li ◽  
Lingling Qi ◽  
Lingjiang Zhang ◽  
Hao Xu
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Fast Response ◽  
Tunnel Construction ◽  
Hydrothermal Route ◽  
Sensing Properties ◽  
Response Recovery ◽  
Gas Sensing Properties ◽  
Gas Response ◽  
Scanning Electron

Hierarchical flower-like WO3 · H2O microspheres assembled by nanosheets were successfully prepared through a simple hydrothermal route. Field emission scanning electron microscopy results indicate that the flower-like WO3 · H2O microspheres are composed of numerous nanosheets, which are interconnected with each other in the sphere shape. In addition, the gas sensing properties of the hierarchical WO3 · H2O microspheres were investigated. It is found that the gas sensor based on the hierarchical WO3 · H2O architectures exhibits excellent gas sensing properties towards H2S gas, including high gas response and fast response/recovery speed.

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