VO₂nanorods for efficient performance in thermal fluids and sensors

Abstract

VO2 (B) nanorods with average width ranging between 50-100 nm are synthesized via a hydrothermal method and the post hydrothermal treatment drying temperature is found to be influential in their overall phase and growth morphology evolution. The nanorods with unusually high optical bandgap for a VO2 material are effective in enhancing the thermal performance of ethylene glycol nanofluids over a wide temperature range as is indicated by the temperature dependent thermal conductivity measurements. Humidity and LPG sensors fabricated using the VO2 (B) nanorods bear testament to their efficient sensing performance, which can be partially attributed to the mesoporous nature of the nanorods.

Room temperature vanadium dioxide–carbon nanotube gas sensors made via continuous hydrothermal flow synthesis

“…Sensing mechanisms previously used to describe the responses of vanadium oxide based sensors 12 were found to be applicable in this study in conjunction with those applied to other metal oxide devices operating at room temperature.…”

“…Strelcov et al reported that by operating a VO2 nanowire sensor close to the materials' metal-semiconductor transition temperature (≈ 68 ̊ C), conductance through the material became highly sensitive to the molecular composition of the environment, even enabling the detection of inert gases 13 . Depending on the structures formed and their respective oxidation states, vanadium oxides can also display sensitivity to water (H2O) and are thus suitable for use as humidity sensors 12,14,27,28 .…”

“…Monoclinic vanadium dioxide [VO2(M)] is a particularly interesting thermochromic material 11 , with a range of polymorphs that have attracted interest for use in gas sensing [12][13][14][15] . A variety of morphologies have been obtained for vanadium oxides (VOx), including nanofibers 16 , nano-belts 17 , nanorods 12,[18][19][20] and nanowires (NWs) 13 .…”

“…Monoclinic vanadium dioxide [VO2(M)] is a particularly interesting thermochromic material 11 , with a range of polymorphs that have attracted interest for use in gas sensing [12][13][14][15] . A variety of morphologies have been obtained for vanadium oxides (VOx), including nanofibers 16 , nano-belts 17 , nanorods 12,[18][19][20] and nanowires (NWs) 13 . Gas sensors using these nanomaterials have been used for the detection of ammonia (NH3) gas [21][22][23] , nitrogen dioxide (NO2) 24 , ethanol (C2H6O) 17,25 , methane (CH4) 26 and liquefied petroleum gas (LPG) 12 , at both ambient (25 ̊ C) and elevated operating temperatures.…”

“…A variety of morphologies have been obtained for vanadium oxides (VOx), including nanofibers 16 , nano-belts 17 , nanorods 12,[18][19][20] and nanowires (NWs) 13 . Gas sensors using these nanomaterials have been used for the detection of ammonia (NH3) gas [21][22][23] , nitrogen dioxide (NO2) 24 , ethanol (C2H6O) 17,25 , methane (CH4) 26 and liquefied petroleum gas (LPG) 12 , at both ambient (25 ̊ C) and elevated operating temperatures. Strelcov et al reported that by operating a VO2 nanowire sensor close to the materials' metal-semiconductor transition temperature (≈ 68 ̊ C), conductance through the material became highly sensitive to the molecular composition of the environment, even enabling the detection of inert gases 13 .…”