▎ 摘　　要

Magnetite-loaded graphene oxide nanocomposites are currently studied as an easily retrievable efficient adsorbent of dyes and heavy metals. Therefore, the search for facile and low cost synthetical methods to prepare them is intensively pursued. This work describes a simple one-pot method to produce superparamagnetic magnetite nanoparticles (Fe3O4), and a hybrid nanocomposite of magnetite nanoparticles decorating reduced graphene oxide (Fe3O4-rGO) by reacting ferrous chloride with urea in water or graphene oxide-water dispersions, respectively. The synthetical method is based on temperature-assisted urea decomposition in water. The final products comprised Fe3O4 nanoparticles or Fe3O4-decorated rGO sheets. Outstandingly, despite the polydisperse nature of Fe3O4, both materials are nearly superparamagnetic, and GO was partially reduced during the Fe3O4-GO preparation to produce Fe3O4-rGO. We propose plausible pathways for the Fe3O4 formation, as well as a preliminary study on methylene blue degradation in water, using the Fe3O4-rGO nanocomposite.