Three-dimensional structure made with nitrogen-doped reduced graphene oxide with spherical porous morphology

Three-dimensional graphene materials (3D) have attracted great interest in recent years due to the outstanding properties that are product of the combination between graphene intrinsic properties and 3D materials macroscopic properties, such as porosity and easy manipulation due to their macroscopic scale dimensions. These characteristics have given them notorious advantage for various applications over other materials. This study reports a methodology to obtain a 3D material made with reduced graphene oxide (rGO) using spherical particles of calcium carbonate (CaCO3) as sacrificial template. CaCO3 particles were coated with graphene oxide (GO), using a layer-by-layer procedure (LbL) and later, templates were removed using acid solution. The obtained monolith retains the shape of the templates. The morphology, thermal stability and chemical composition of the monolith were characterized by several techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoemission spectroscopy (XPS), Raman spectroscopy and infrared spectroscopy (FTIR). The results showed that the obtained monolith has spherical hollow spaces distributed throughout the 3D structure. In addition, physisorption analysis using N2 revealed that the obtained monolith increased 40% its surface area compared to a conventional rGO aerogel prepared without using sacrificial templates. [Display omitted]