Method for preparing Fe3O4 nanoparticle/graphene composite material by sol electrostatic self-assembly process and application thereof

The invention discloses a method for preparing a Fe3O4 nanoparticle/graphene composite material by a sol electrostatic self-assembly process, which comprises the following steps: (1) preparing a Fe(OH)3 sol solution of which the surface is positively charged; (2) preparing a graphene oxide sol of which the surface is negatively charged; and (3) mixing the graphene oxide sol and the Fe(OH)3 sol, magnetically stirring to generate a brownish black precipitate, separating, pouring out the supernate to obtain a Fe(OH)3/graphene oxide composite, and reducing the composite at 300-800 DEG C in a nitrogen atmosphere to obtain the Fe3O4/graphene nano composite material. The composite of the Fe(OH)3 colloidal particles and graphene oxide is performed in the water solution, and thus, the method has the advantages of low cost, energy saving, environment friendliness and simple technique, and can easily implement industrial mass production; and the preparation process of the Fe(OH)3 colloidal particle/graphene oxide composite material has obvious solution variation, and the solution becomes turbid from clear and finally precipitates, so that the supernate can be directly poured out.