Highly Selective and Rapid Detection of Ethanol Using Ni-Functionalized ZnO Nanoflakes Coated Fiber Optic Sensor

Recently, the fabrication of ethanol sensor is of great technological interest toward detection of ethanol in myriad application areas such as fuel and chemical processing, food packaging analysis, breath alcohol analyzers, and clinical applications. Parallelly, the emerging trend of nanotechnology facilitates highly sensitive, miniature, and cut-price sensors with better power consumption. In accordance with this context, the current research work deals with the effect of metal (Ni) functionalization on ZnO nanoflakes for volatile compound (VC) sensing applications. A Co-precipitation method was utilized to synthesize pristine and Ni-functionalized ZnO nanoflakes. Furthermore, various material properties were critically investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive spectrometer. The XRD results have shown that synthesized nanoparticles were in a hexagonal wurzite structure. The SEM image revealed that the average size of the nanoflakes is around 200 nm. A cladding modification technology was employed to fabricate the fiber optic sensor (FOS) head and Ni-functionalized ZnO nanoflakes as the sensing layer was formulated by a dip coating process. Furthermore, the sensor response of Ni-functionalized ZnO nanoflakes was investigated for various VCs such as acetone, ammonia, ethanol, methanol, hexane, and chloroform. Noticeably, the FOS based on Ni-functionalized ZnO showed better selectivity toward ethanol along with enhanced sensitivity (~30.04) than pristine ZnO. Thus, the functionalization of Ni enhances the gas sensing competency of ZnO through the catalytic property, indicating the potency of the proposed sensor as a substantial tool for ethanol detection.