One-pot synthesis of Fe, Co and Ni-doped carbon xerogels and their magnetic properties

Transition metal (Fe, Co and Ni)-doped carbon xerogels were synthesized by a facile one-pot pyrolysis of the sol-gel polymer of resorcinol and formaldehyde in the presence of the corresponding metal nitrates. N2 adsorption-desorption, scanning and transmission electron microscopy proved that addition of different metals could exert a remarkable influence on the textural properties. From X-ray diffraction the phases of the metallic species were identified. Scanning electron microscopy images revealed that the surface morphologies of resultant metal-carbon xerogels were composed of carbon microspheres with diameters from 5 to 15 µm. Transmission electron microscopy observations illustrated that Ni-carbon xerogel was made of uniform carbon nanotubes which differed from the approximative core/shell structures of Fe- and Co-carbon xerogels. Measurements on magnetic properties indicated that the Fe-, Co-, and Ni-carbon xerogels exhibited typical ferromagnetic characteristics at room temperature.