ABSTRACT
In this study, we fabricated a composite of NiO-ZnO/PANI-CNTs on a fluorine tin oxide (FTO) electrode and examined the electrochemical sensing behavior of the modified electrode to detect methanol in aqueous solution. The structural, morphological, and electrochemical properties of the composite were characterized using various methods such as X-ray diffraction (XRD), EDS, FTIR, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and electrochemical techniques such as cyclic voltammetry (CV) and chronoamperometry (CA). The composite-based electrode showed excellent electrocatalytic activity and selectivity for methanol oxidation. The calibration equation obtained was ΔI = 0.0003 × CMeOH + 0.02811, with a high correlation coefficient of 0.9993, over a wide detection range of 0 to 500 mM. The material exhibits great potential for the fabrication of sensors to detect methanol in commercial products. Real gasoline samples have been selected to evaluate the practical performance and feasibility of this as-prepared sensor. The experimental data indicated that the recovery of gasoline samples is about 98%, indicating this to be an appropriate detection procedure for effective electrochemical determination of MeOH in real gasoline samples.
ABSTRACT
Silica/polypyrrole nanocomposites without dopant (SiO2/PPy) and with oxalate dopant (SiO2/PPyOx) were synthesized using polymerization of pyrrole in the presence of nano SiO2. Synthesized SiO2/PPy and SiO2/PPyOx were characterized by FTIR, SEM, TEM and EDX and their electrical conductivities were determined by CV method through the two-point-electrode without electrolyte. The corrosion protection performance of polyvinylbutyral (PVB) coatings containing SiO2/PPyOx was evaluated and compared with that of pure PVB coatings and of PVB coatings containing SiO2/PPy by electrochemical impedance spectroscopy and adhesion measurement. The results show that electrical conductivities of SiO2/PPy and SiO2/PPyOx were 0.181 and 0.109 S/cm, respectively. The ratio of PPy on SiO2 in SiO2/PPy and SiO2/PPyOx composites was 0.77/1 and the ratio of oxalate on PPy in SiO2/PPyOx composite was 1.24/1. SiO2/PPy and SiO2/PPyOx improved corrosion resistance and adhesion of PVB coatings. The presence of oxalate in SiO2/PPyOx significantly enhanced the effect of SiO2/PPy on the protection performance of PVB coatings.
