Structural, Dielectric, and Electrochemical Behaviour for Polyaniline, Graphene Oxide and their Composite's Mechanism Towards Dichromate Sensing

Polyaniline (PANI) as a conducting polymer, graphene oxide (GO), and their composite (PAGO) were synthesized and studied by X-ray diffraction (XRD), Fourier transforms infra-red (FT-IR), scan electron microscopy (SEM), Brauner-Emmet-Teller (BET), and X-ray photoelectron spectroscopy (XPS) to understand the mechanism of K2Cr2O7 detection through electrochemical techniques with different concentration (10-100 ppm). The electrochemical techniques used for detection are cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance techniques (EIS). PANI and GO show different behaviour for electrochemical sensing towards the Cr2O7 - 2 ion. GO depends upon the intercalation and adsorption owing to its high c space. PANI depends on the redox process of functional groups on its surface and shows that Cr interacts with C = N and demolishes the peak at CV. The composite was closer to PANI's behaviour, owing to the active functional groups on the composite's surface, with the presence of intercalation. The dielectric studies show that the composite has higher AC conductivity (sigma ac), dielectric constant (epsilon '), and dielectric loss (epsilon ''), which gives the composite higher electric charge on its surface than its constituents. The composite was checked after K2Cr2O7 sensing using SEM, EDX, and XPS. It shows that the Cr interacts with N in PANI at -0.8 V vs. Ag/Ag+ reference electrode.