Synthesis, Characterization, and Catalytic Applications of Core–Shell Magnetic Carbonaceous Nanocomposites

Abstract

Magnetic resorcinol/formaldehyde resin (RF) and silica/RF nanocomposites with well-defined coreshell architecture and tunable structural parameters had been prepared via the extended Stober method. The carbon counterparts with similar structure and morphology can be obtained by thermal-treating the polymer precursors under N-2 atmosphere. The prepared materials were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Mossbauer spectroscopy, N-2 physical adsorption/desorption, and thermogravimetric analysis. The catalytic applications of the synthesized magnetic nanocomposites were also explored. It has been shown that the magnetite core was oxidized to gamma-Fe2O3 during polymer coating process and further reduced to original Fe3O4 phase during carbonization. In addition, the iron oxide core can react with the shell when carbonization temperature reaches 700 degrees C. The structural stability of magnetic silica/RF is superior to magnetic RF because of the existence of an inner silica shell. Through a simple depositionprecipitate method, active platinum nanoparticles can be loaded in high dispersity onto the surface of the nanocomposites. The constructed magnetic catalysts are very active in hydrogenation of nitroarenes to corresponding amines and can be separated facilely with an external magnetic field.