Carbon nanotubes-magnetite nanocomposites from solvothermal processes: Formation, characterization, and enhanced electrical properties

Carbon nanotubes (CNTs)-magnetite nanocomposite with 20-30-nm magnetite particles attached onto CNTs has been successfully prepared for the first time by in situ solvothermal synthesis from the precursor of Fe-urea coordination complex (Fe[(NH2)(2)CO](6)(NO3)(3)) and CNTs. The effects of CNTs and various processing parameters on ultimate composites characteristics were investigated. It has been found that pure CNTs-magnetite nanocomposite was obtained in an ethylenediamine medium at 200 degreesC for 50 h with the weight ratio of Fe[(NH2)(2)CO](6)(NO3)(3):CNTs = 10:1. XRD, BET, TEM, EDS, and a Mossbauer spectrum were used to characterize the final product. A possible formation mechanism of the CNTs-magnetite nanocomposite was suggested. It has been concluded that a suitable amount of water introduced by CNTs is critical for preparing CNTs-magnetite nanocomposite. The addition of CNTs in the composite increased the electrical conductivity by about 32% from 1.9 to 2.5 S cm(-1), compared with the composite without CNTs. The relative density measurement and microstructure characterization performed by SEM showed that the percolation effect of CNTs and a good dispersion of CNTs in the matrix would lead to an effective and obvious improvement on the electrical conductivity.