The invention provides a
nitrogen-doped and carbon-coated magnetic
nanoparticle composite microspheres and a preparation method thereof, and belongs to the technical field of materials with an electromagnetic function. According to the method, a glycerin
metal complex and a nitrogenous
organic compound are taken as main raw materials. A monodispersed glycerin
metal complex precursor is prepared according to a self-template method at first; then the surface of the precursor is coated to form a shell by virtue of in-situ
polymerization for nitrogenous organic monomers, and a
carbon source and anitrogen source are introduced; and finally, calcining is carried out under an
inert gas, and a core is subjected to
thermal decomposition to form
magnetic nanoparticles while the shell is carbonizedto form
nitrogen-
doped carbon. The
nitrogen-doped and carbon-coated magnetic
nanoparticle composite microspheres are green and environment-friendly, and efficient and time-saving in preparation process, and suitable for being prepared in a large scale; the electromagnetic parameters of the composite microspheres and the sizes of the
magnetic nanoparticles can be regulated and controlled by changing the
mass ratio of
metal salt to the nitrogenous organic monomers, and an annealing temperature, so that
impedance matching and attenuation characteristic are achieved; and the prepared composite microspheres are high in absorption intensity for electromagnetic wave, wide in effective
absorption frequency band, easy to prepare in a large scale, and capable of meeting many use needs.