Layer-by-layer preparation of electromagnetic NH2-SiO2/polypyrrole/Ni nanocomposites, characterization and their electrochemical properties

Combinations of organic conducting polymers and inorganic electromagnetic materials have drawn much attention in various fields like energy storage materials, biosensors, biomedical applications, catalysis and removal of heavy metals from water. In this investigation an attempt is made to decorate polypyrrole (PPy), a semiconducting electroactive polymer, with Ni nanoparticles on a functional silica (SiO2) support. First, amine-functionalized mesoporous NH2-SiO2 seed particles are prepared by the sol-gel method using hexamethylenediamine as a surface-functionalizing agent and cetyltrimethylammonium bromide as a template. Second, NH2-SiO2/PPy composite particles are prepared via in situ seeded chemical oxidative polymerization of pyrrole. The surface of the NH2-SiO2/PPy composite particles is finally immobilized/doped with Ni nanoparticles via in situ chemical reduction of Ni(II) salt. The surface morphology, structure modification, size distribution and magnetic properties of the prepared NH2-SiO2/PPy/Ni nanocomposite particles are confirmed using various spectroscopic techniques, electron microscopy, Brunauer-Emmett-Teller measurements, X-ray diffraction and vibrating sample magnetometry. The NH2-SiO2/PPy/Ni nanocomposite particles possess good paramagnetic properties. A comparative study of electrochemical properties revealed improvement in specific capacitance of NH2-SiO2/PPy composite compared to PPy but further decoration with Ni nanoparticles under alkaline condition reduces the capacitance value. (C) 2022 Society of Industrial Chemistry.