Document Type: Research Article
Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, I.R. IRAN
Department of Chemistry, Sharif University of Technology, Tehran, I.R. IRAN
In this study, a multi nano sensor was fabricated for the simultaneous detection of carbon dioxide, methane, ethanol and ammonia gases, and its electrochemical response to various concentrations of these gases was investigated. In order to fabricate this multi nano sensor, in the first phase, the Graphene-Oxide/Polyaniline (GO/PANI) nano-composite was synthesized. Chemical composition, morphology and the structure of the nano-composite was studied by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). The results indicate that the GO successfully synthesized and the polyaniline particles are well bonded on the surface of the GO sheets. In the second phase, the formed nano-composite was placed on silver coated electrodes and then, by placing the nanoparticles of aluminum oxide, zinc oxide, tin oxide and titanium oxide, the different parts of the multi-nano sensor were became more sensitive toward the four mentioned gases. The responsiveness and sensitivity of the multi-nano sensor to each of the gases were measured by amperometric experiments and the results showed that the sensitivity of multi-nano sensor fabricated to detection of the above gases is acceptable. The results of the electrochemical tests showed that the response of each multi-nano sensor component to a mixture of the above four gas is defined as a four unknown equation and with considering the responses of 4 multi-nano sensor components simultaneously to the 4-gas mixture, 4 × 4unknown equations are obtained, which by solving the equation one can be found the exact concentration of each of the 4 measured gases.