Abstract
ZnO nanoparticles were produced by flame spray pyrolysis using zinc naphthenate as a precursor dissolved in toluene/acetonitrile (80/20 vol%). The particles properties were analyzed by XRD, BET. The ZnO particle size and morphology was observed by SEM and HR-TEM revealing spheroidal, hexagonal, and rod-like morphologies. The crystallite sizes of ZnO spheroidal and hexagonal particles ranged from 10-20 nm. ZnO nanorods were ranged from 10-20 nm in width and 20-50 nm in length. Sensing films were produced by mixing the nanoparticles into an organic paste composed of terpineol and ethyl cellulose as a vehicle binder. The paste was doctor-bladed onto Al2O3 substrates interdigitated with Au electrodes. The morphology of the sensing films was analyzed by optical microscopy and SEM analysis. Cracking of the sensing films during annealing process was improved by varying the heating conditions. The gas sensing of ethanol (25-250 ppm) was studied at 400 °C in dry air containing SiC as the fluidized particles. The oxidation of ethanol on the surface of the semiconductor was confirmed by mass spectroscopy (MS). The effect of micro-cracks was quantitatively accounted for as a provider of extra exposed edges. The sensitivity decreased notably with increasing crack of sensing films. It can be observed that crack widths were reduced with decreasing heating rates. Crack-free of thick (5 μm) ZnO films evidently showed higher sensor signal and faster response times (within seconds) than cracked sensor. The sensor signal increased and the response time decreased with increasing ethanol concentration.
Highlights
In the field of gas sensors, it is well known that ethanol vapor is one of the most exhaustively studied gases
CAS No 744057-5 [96]) from the substrates are visible in the A0, S1 and S6, especially, the sensors S1 and S6 showed Zinc oxide (ZnO) peaks, which confirm the ZnO thick film sensing layer doctor-bladed on Au/Al2O3 substrates
The hexagonal phase of ZnO nanoparticles were made by flame spray pyrolysis of zinc naphthenate in toluene and acetonitrile
Summary
In the field of gas sensors, it is well known that ethanol vapor is one of the most exhaustively studied gases. An ethanol sensor based on ZnO nanorods prepared by hydrothermal method [24] showed high sensitivity to ethanol concentration ranging from 10 to 2000 ppm at 330°C, with good response and recovery time. Pure ZnO nanorods and nano-needles produced by hybrid induction and laser heating (HILH) technique showed capability to produce sensors with good sensor signal at a maximum temperature around 400°C for a concentration of 100 ppm of volatile organic compounds (VOCs) including acetone, toluene, and ethanol. The gas sensing results showed that the sensor signal for detection 400 ppm ethanol vapor was about 20 at an operating temperature of 250 oC [38]. It is important to investigate the most suitable thickness and sensing surface for the ethanol sensor based on flame-made ZnO nanoparticles. Crack-free thin film sensing layer should show a good sensing behavior of sensor materials based on flame-made ZnO nanoparticles
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
