A Novel Graphene-Based Nanosensor for Detection of Ethanol Gas

This study is the first phase (a research model) of the construction of a multi-nanobiosensor to detect multiple gases simultaneously that will be published in a separate article. In this study, a nanobiosensor was fabricated for ethanol gas detection, and its electrochemical response to various concentrations of this gas was studied. In the first phase, in order to fabricate this nanobiosensor, the graphene oxide/polyaniline (GO/PANI) nanocomposite was synthesized. Chemical composition, morphology and the structure of the nanocomposites were studied by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The results show that the synthesis of graphene oxide (GO) is done correctly and the polyaniline (PANI) particles are well bonded on the surface of the GO sheets as physically and chemically. Owning to the formation of the correct GO/PANI nanocomposite, the analyses indicate that the formation of PANI polymer chains on the surface of GO have led to the deformation of graphene sheets, which are normally flattened and uniformed sheets into the form of non-flattened and non-uniformed sheets. In the second phase, the formed nanocomposite was placed on silver-coated electrodes, and then, by placing the nanoparticles of tin oxide, the nanobiosensors were sensitive toward the ethanol gas. Through the amperometric experiments, responsiveness and sensitivity and selectivity of the nanobiosensors to each of the ethanol, carbon dioxide, methane and ammonia gases were measured and the results showed that the sensitivity of nanobiosensor fabricated for detection of the ethanol gas is acceptable. The results of the electrochemical tests showed that the nanobiosensors also have responded slightly to ammonia and methane.