Highly sensitive wireless H2S gas sensors at room temperature based on CuO-SWCNT hybrid nanomaterials

Detection of H2S in very low concentrations with innovative functional materials is of key importance in oil and gas industries. One approach to control the limit of detection for gas sensors is to engineer the shape of sensing nanostructures to develop high performance gas sensors. By controlling the process parameters in synthesizing of CuO nanostructures, programming the limit of detection has been obtained up to 100 ppb H2S for CuO-SWCNT nanostructures at room temperature. Gas sensing evaluation of nanomaterials indicates the role of surface to volume ratio on the performance of the sensors. The crystalline structure, chemical composition and morphological characterization have been studied by X-ray diffraction, Furrier transform IR spectroscopy, Raman spectroscopy and field emission scanning electron microscopy. The CuO-SWCNT nanomaterials has been immobilized on top-side of commercial 13.56MHz radio frequency identification (RFID) tag by drop-casting to produce tag sensors. Due to change in radar cross section of the fabricated wireless devices, a reduction of reflectance and shift of peak frequency toward lower values is observed by increasing the gas concentration. Repeatability and long life-time (30 days) of fabricated sensors indicate their effective potential for remote healthcare and environmental monitoring applications. (C) 2016 Elsevier B.V. All rights reserved.