Pt- and Pd-decorated MWCNTs for vapour and gas detection at room temperature (original) (raw)
Related papers
Pt and Pd-nanoclusters functionalized carbon nanotubes networked films for sub-ppm gas sensors
Sensors and Actuators B-chemical, 2008
A gas chemiresistor, fabricated onto alumina using multi-walled carbon nanotubes (MWCNTs) networked films grown by radiofrequency plasma enhanced chemical vapor deposition (RF-PECVD) technology, is described for high-performance gas detection, at an operating temperature of 200 • C. Functionalizations of MWCNTs tangled bundle-films with nominally 5-nm thick Pt-and Pd-nanoclusters, prepared by magnetron sputtering, provide higher sensitivity for significantly enhanced gas detection of NO 2 , H 2 S, NH 3 , CO, up to a low limit of sub-ppm level. The measured electrical conductance of the functionalized MWC-NTs upon gas exposures is modulated by charge transfer with p-type semiconducting characteristics. Ptand Pd-nanoclusters functionalized MWCNTs gas sensors exhibited better performances compared to unfunctionalized MWCNTs, making them promising candidates for air-pollutants environmental monitoring. Simple electronic interface for the chemiresistor has been developed with a voltage output of the sensor signal.
Lecture Notes Electrical Engineering, 2008
Multi walled carbon nanotubes (MWCNTs) are known to respond well to a range of gases and vapours. Metallic additives are often introduced to improve the sensitivity and selectivity to some gases. Here the difference in response between MWCNT sensors with and without a metal additive is discussed for a range of gases. Resistive sensors fabricated from chemical vapour deposition (CVD) grown multi walled carbon nanotubes (MWCNTs) collected between gold microelectrodes by dielectrophoresis are presented as a cheap, scaleable and facile method of producing carbon nanotube gas sensors. The MWCNTs sensors were exposed to a series of test gases including NO 2 , NH 3 , CO and H 2 and exhibited low ppm. detection at room temperature. Increasing the temperature not only reduced the recovery time of the sensors, but also increased the sensitivity to some gases whilst a decrease in the sensitivity was seen for other gases.
Carbon nanotubes as new materials for gas sensing applications
Journal of The European Ceramic Society, 2004
Carbon nanotubes (CNTs) deposited by plasma enhanced chemical vapor deposition on Si3N4/Si substrates provided with Pt electrodes have been investigated as resistive gas sensors towards NO2. The electrical response has been measured exposing the films to sub-ppm NO2 concentrations (10–100 ppb in dry air) at different operating temperatures ranging between 25 and 250 °C. The response to NO2 has been found to be at maximum at around 165 °C. Upon exposure to NO2 the electrical resistance of randomly oriented CNTs is found to decrease. The prepared films show reasonable dynamic of the electrical response and high reproducibility of the electrical properties. The resistance decrease of the CNTs when exposed to NO2 gas and the sensor response to concentrations as low as 10 ppb NO2, suggest the possibility to utilize CNTs as new sensors for air-quality monitoring.
Synthesis of Carbon Nanotubes and Volatile Organic Compounds Detection
MATEC Web of Conferences, 2016
In this work, the adsorption effect of volatile organic compounds (chloroacetophenone, acetonitrile and hexane) towards the change of resistance of CNTs pellet as sensor signal was investigated. CNTs used in this research were synthesized using Floating Catalyst-Chemical Vapor Deposition (FC-CVD) method in optimum condition. The synthesized CNTs were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Raman Spectroscopy. The variation of resistance changes towards the tested gases were recorded using a multimeter. CNTs sensor pellet showed good responses towards the tested gases, however, the sensitivity, response time and recovery time of sensor pellet need to be optimized.
Diamond and Related Materials, 2016
A dichloromethane (DCM) sensor with a high response magnitude was successfully fabricated using the integration of single-walled carbon nanotubes (SWNTs), poly(methyl methacrylate) (PMMA) and platinum nanoparticles (Pt NPs). A pristine SWNT network was first formed by drop-casting onto printed circuit board (PCB) substrates. Next, PMMA was coated onto the pre-dropped SWNT network by spin coating using a PMMA-toluene solution, followed by the deposition of Pt NPs by electron-beam evaporation (hereafter referred to as Pt/PMMA/SWNT). The Pt/PMMA/SWNT enabled an approximately 69-fold improvement in DCM detection compared to pristine SWNT. The high response magnitude of the Pt/PMMA/SWNT was successfully achieved because of the incorporation of PMMA and Pt functions. Swelling of the PMMA matrix as a result of DCM adsorption leads to PMMA volume expansion, thereby increasing the SWNT-SWNT distance, which results in an increase in the resistance. Pt NPs promote the dissociation of DCM to CO, and consequently the CO oxidation on the Pt NPs catalyst and electron donation from Pt NPs to SWNTs, resulting in an increase in the resistance. Moreover, a linear relationship was obtained between the sensor response of the Pt/PMMA/SWNT and the concentration of DCM. These results suggest that the integration of SWNTs with PMMA and Pt NPs is a promising approach for improving DCM detection at room temperature.
International Journal of Hydrogen Energy, 2017
Fast detection of H 2 gas at room temperature has constantly remained a challenge. The metal-oxide based gas sensors have shown excellent sensing properties for gases like H 2 , NO, CO and NH 3. In the present work, the H 2 gas sensing characteristics of multiwalled carbon nanotubes based hybrid sensor (F-MWCNTs/TiO 2 /Pt) has been reported. The fabricated sensor shows 3.9% sensitivity for low concentration i.e. 0.05% of H 2 with good repeatability and stability at room temperature. The sensing response of F-MWCNTs/TiO 2 / Pt is interrelated to change in their resistance on the introduction of H 2 gas and this phenomenon is required for deep understanding the effect of H 2 adsorption on their electronic conduction. The improvement in sensitivity of F-MWCNTs/TiO 2 /Pt as compared to MWCNTs/TiO 2 towards H 2 is because of the catalytic role of dispersed Pt nanoparticles deposited by sputtering.
Carbon Nanotube Sensors for Gas and Organic Vapor Detection
Nano Letters, 2003
A gas sensor, fabricated by the simple casting of single-walled carbon nanotubes (SWNTs) on an interdigitated electrode (IDE), is presented for gas and organic vapor detection at room temperature. The sensor responses are linear for concentrations of sub ppm to hundreds of ppm with detection limits of 44 ppb for NO 2 and 262 ppb for nitrotoluene. The time is on the order of seconds for the detection response and minutes for the recovery. The variation of the sensitivity is less than 6% for all of the tested devices, comparable with commercial metal oxide or polymer microfilm sensors while retaining the room-temperature high sensitivity of the SWNT transistor sensors and manufacturability of the commercial sensors. The extended detection capability from gas to organic vapors is attributed to direct charge transfer on individual semiconducting SWNT conductivity with additional electron hopping effects on intertube conductivity through physically adsorbed molecules between SWNTs.
TOPICAL REVIEW: Recent progress in carbon nanotube-based gas sensors
Nanotechnol, 2008
The development of carbon nanotube-(CNTs-)based gas sensors and sensor arrays has attracted intensive research interest in the last several years because of their potential for the selective and rapid detection of various gaseous species by novel nanostructures integrated in miniature and low-power consuming electronics. Chemiresistors and chemical field effect transistors are probably the most promising types of gas nanosensors. In these sensors, the electrical properties of nanostructures are dramatically changed when exposed to the target gas analytes. In this review, recent progress on the development of different types of CNT-based nanosensors is summarized. The focus was placed on the means used by various researchers to improve the sensing performance (sensitivity, selectivity and response time) through the rational functionalization of CNTs with different methods (covalent and non-covalent) and with different materials (polymers and metals).
Sensors and Actuators B: Chemical, 2008
Novel hybrid gas-sensitive materials were fabricated by means of metal-decorated multiwall carbon nanotubes (MWCNT) dispersed on nanoparticle metal oxides. The MWCNT were initially functionalized in an oxygen plasma for improving their dispersion and surface reactivity, and then they were decorated with metal nano-clusters by thermally evaporating gold or silver on the MWCNT. Active layers for gas sensing applications were obtained by adding a small amount of metal-decorated MWCNT to two different types of metal oxides (SnO 2 and WO 3 ). The hybrid materials have been analyzed by means of XPS, TEM and SEM. The gas sensing potential of the fabricated hybrid materials has been tested upon exposure to different hazardous species, specifically NO 2 , CO, C 6 H 6 and NH 3 , at low operating temperature. research topic consists of gas sensors based on plasma functionalised carbon nanotubes.