Optimization of hydrazine sensing electrode based on bi-doped polypyrrole/Au nanoparticles composite

E.GUTIÉRREZ PINEDA; L.A. AZPEITIA; PRESA, M.J. RODRÍGUEZ; A.E. BOLZÁN; C.A. GERVASI

Mar del Plata

Congreso; 34th Topical Meeting of the international Society of Electrochemistry; 2023

International Society of Electrochemistry

Hydrazine is extensively used in many practical applications as an efficient reducing agent however, being hydrazine a carcinogenic agent, it can produce damage to liver and brain. Thus, its determination is of utmost importance for environment protection and health [1]. Among the different available strategies, the electrochemical method is preferred due to its high sensitivity and simplicity. PPy-modified substrates were synthesized, characterized, and finally ranked according to their ability to meet required performance criteria as precursor electrode material in the preparation of sensing platforms. That is, after characterization, a tuned benchmarking method was devised and executed to select the one electrode that exhibits best potential for its use in hydrazine electrochemical sensors. Electrodes modified with bi-doped polypyrrole (PPy-DA) retain some desirable aspects of each single-anion doped film. PPy-DA electropolymerization was carried out in a KClO4 + NaC7H5O3 solution. Synthesis of the bi-doped conductive polymer was studied as a function of the polymerization time and solution composition. Morphological, spectroscopic and electrical characteristics of the polymer films were determined by means of SEM and XPS and Raman spectroscopies. The features of the bi-doped PPy film were compared to those resulting from electropolymerization in simple NaC7H5O3 (PPy-Sa) or KClO4 (PPy-ClO4) solutions. Comparison was also carried out by considering different PPy-DA films with varying dopant concentration in the polymerization bath and with changing electropolymerization time. The presence of C7H5O3- ions favours the formation of a three-dimensional tubular structure whereas ClO4- ions contribute to increase conductivity and electrocatalytic activity of the PPy-DA film. The tubular 3D structure of the electrode surface serves as an open extended-area matrix for the electrodeposition of gold nanoparticles (AuNPs). Electrodeposited AuNPs acting as electrocatalytic centres for hydrazine electrooxidation were successfully tested for voltammetric sensing (Figure 1). To this end, the PPy-DA film was patterned with an array of AuNPs electrodeposited by applying a suitable potential perturbation signal [2].