Impact of mesoporous SiO2 support for Ni/polypyrrole nanocomposite particles on their capacitive performance

Electro-conducting polypyrrole (PPy) coated H2N-SiO2/Ni nanocomposite particles are prepared by a three-step process. The objective is to analyze the influence of porous functional SiO2 support on the electrochemical performance of the prepared H2N-SiO2/Ni/PPy nanocomposite particles. H2N-SiO2 support is first prepared by a modified sol-gel method and then co-ordinated with Ni nanoparticles via an amine functionality. Finally, H2N-SiO2/Ni/PPy nanocomposite particles are prepared by in situ chemical oxidative polymerization of pyrrole using citric acid as a dopant. Fourier Transform IR (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the formation of co-ordinated Ni/Ni2+ nanoparticles and a PPy layer with almost a core-shell type morphology. The mesoporous surface structure of H2N-SiO2 core-particles is confirmed from the morphological study and the specific surface area gradually decreased from 496 m(2) g(-1) to 59 m(2) g(-1) following subsequent surface modification with Ni nanoparticles and the PPy layer. The ultimate nanocomposite particles had paramagnetic properties and the magnetization value is 4.8 emu g(-1). Comparative electrochemical performance between electrodes made from the respective PPy, Ni/PPy and H2N-SiO2/Ni/PPy showed the highest specific capacitance value (982.6 F g(-1) from cyclic voltammetry curves) for the H2N-SiO2/Ni/PPy nanocomposite. The H2N-SiO2/Ni/PPy nanocomposite electrode is fairly stable during cycling measurement. The results indicated that the use of mesoporous functional SiO2 support remarkably improved the mechanical stability and capacitive performance of the H2N-SiO2/Ni/PPy nanocomposite electrode, suitable for application in energy storage devices.

Automated summary

In this study, H2N-SiO2/Ni/PPy nanocomposite particles were prepared and the influence of porous functional SiO2 support on the electrochemical performance was analyzed. The formation of coordinated Ni/Ni2+ nanoparticles and a core-shell morphology PPy layer were confirmed. Comparative electrochemical performance demonstrated that the H2N-SiO2/Ni/PPy nanocomposite exhibited the highest specific capacitance and stability.