C60Pd coordination oligomers inside ordered mesoporous silica: formation, morphology, and electrochemical properties

This study reports the formation and characterization of ordered mesoporous silica particles, MCM-48, used as supports to form C₆₀Pd@MCM-48 nanocomposites. Silica nanopores were impregnated with a benzene solution containing fullerene C₆₀ via capillary action, and then, this fullerene incorporated into the silica pores was chemically polymerized in a solution containing a precursor to the polymerization process. The morphology and structure of the resulting composite were investigated using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, energy-dispersive X-ray analysis, infrared spectroscopy, nitrogen adsorption–desorption, and thermogravimetry. The C₆₀Pd polymer was extracted from the composite and formed spherical nanoparticles with a diameter of 2–3 nm. The C₆₀Pd@MCM-48 composite exhibited electrochemical activity both in positive and negative potential ranges. Rates of both processes and the amount of oligomeric material involved in the electrochemical process were controlled by counterion transport through the silica pores filled with the C₆₀Pd phase. The interaction between the coordination fullerene oligomer and the defected silica surface led to the easier reduction of the C₆₀Pd phase in comparison to the pristine fullerene polymer deposited directly on the electrode surface.