In this work, the impact of pH (ranging between 2 and 5) on the electrochemical behavior of a prepared stable suspension of nanopolyaniline (nPANI) particles, which were dispersed as a stable phase in HCl solutions on the gold electrode surface, was investigated and compared using electrochemical methods, including cyclic voltammetry (CV) and chronoamperometry examinations. The obtained results for both pH = 2 and 3 showed two redox conversions within the polyaniline structure, which are controlled by the adsorption and diffusion mechanisms of nPANI particles. The total number of redox-active sites per nPANI particles increased with a decrease in pH, and the corresponding adsorption parameters (θmax and ΔG0ads) were calculated. Moreover, the electrochemical results for the effect of pH on the adsorption of nPANI particles on the gold electrode surface were complemented using surface analysis methods, including field emission scanning electron microscopy (FE-SEM) and EDX analysis. The stability of suspensions prepared in hydrochloric acid was examined over time using UV–vis spectrum technique and zeta potential measurement.

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