Lateral Size-Controlled Sulfur-Doped Graphene Aerogels with Tunable Electrical and Magnetic Properties

Abstract

Graphene aerogel, an ultralight and highly porous material, shows promise for applications including energy storage, environmental sustainability, electronics, and biomedical fields. The roles of the lateral sheet size and heteroatom doping in graphene are key to its properties. In this study, we examine the combined effect of lateral size and sulfur (S) doping on the electrical and magnetic properties of reduced graphene oxide aerogel (rGA). A sonication-assisted method is used to control the lateral size of graphene oxide (GO) sheets: large-lateral-size GO (GO1) and small-lateral-size GO (GO2). The rGA is synthesized using a hydrothermal-assisted self-assembly process and characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM). The electrical conductivity of rGA1 increases ∼114% after S-doping at 1.44 at.%, while for rGA2, it rises ∼74% at an S-doping of 2.10 at.%. Both S-doped rGA1 and rGA2 show diamagnetic behavior at room temperature (RT) and show temperature-dependent magnetic responses. The mass magnetization of both S-doped rGA1 and rGA2 improves by ∼213% and ∼81%, respectively, at RT. These results indicate that variations in lateral size and S-doping greatly affect the structural, electrical, and magnetic properties of graphene aerogels.