Synthesis of hyperbranched polyferrocenylsilanes as preceramic polymers for Fe/Si/C ceramic microspheres with porous structures

As organometallic polymers containing Fe and Si in the main chain, hyperbranched polyferrocenylsilanes (PFS) have great potential to be Fe/Si/C ceramic precursors. In this study, three kinds of hyperbranched PFS with different crosslinking structures were synthesized by the reaction between ferrocenyl dilithium and one or two of trichloromethylsilane, dichlorodimethylsilane, and dichloromethylvinylsilane. The compositions and structures of these polymers were characterized by nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared (FT-IR) spectroscopy, and thermal gravimetric analysis. With respect to their ceramic yield and solubility, the potential of the obtained PFS to be used as ceramic precursors was evaluated. Moreover, ceramic microspheres with porous structures were obtained by pyrolysis of the hyperbranched PFS at different temperatures, which were characterized by FT-IR, X-ray diffraction, vibrating sample magnetometer, and element analysis. By introducing Fe to the original precursors, the ceramic microspheres exhibited catalytic properties with the presence of Fe nanoparticles on the surface of the internal pores. The porous Fe/Si/C ceramic microspheres made from the hyperbranched PFS have significant potential applications in the field of catalyst supports, energy storage, and gas separation, especially in harsh environments.