A Simple Route to Synthesize Mixed BiPr Oxide Nanoparticles and Polyaniline Composites with Enhanced l-Cysteine Sensing Properties

BiPr oxide nanoparticles were successfully synthesized via a facile surfactant-free hydrothermal route using sodium bismuthate and praseodymium nitrate, and polyaniline/BiPr oxide nanoparticles were also obtained. The products were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy. The obtained nanoparticles with a diameter of about 50–200 nm are composed of polycrystalline structures with rhombohedral Bi_0.4Pr_0.6O_1.5, monoclinic Bi₂O₃ and monoclinic Pr₅O₉ phases. Irregular nanoscale polyaniline particles cover the surface of the BiPr oxide. A pair of quasi-reversible cyclic voltammetry (CV) peaks are located at −0.04 V and −0.67 V, respectively, at the BiPr oxide nanoparticle-modified glassy carbon electrode (GCE) in 0.1 M KCl solution with 2 mM l-cysteine. The anodic CV peak shifts positively to +0.14 V and the cathodic CV peak shifts negatively to −0.82 V using the polyaniline/BiPr oxide nanoparticle-modified GCE. The linear range and detection limit are 0.005–2 mM and 1.18 μM, 0.0005–2 mM and 0.16 μM for the GCE modified with BiPr oxide nanoparticles and polyaniline composites, respectively. Polyaniline greatly enhances the electrochemical sensing properties of the BiPr oxide nanoparticle-modified GCE.