A facile and efficient strategy is described for the fabrication of soluble reduced graphene oxide (rGO) sheets. Different from the conventional strategies, the proposed method is based on the reduction of graphene oxide by an endogenous reducing agent from a most widely used and cost-effective solvent, without adding any other toxic reducing agent. Simultaneously, this solvent can serve as an effective stabilizer, avoiding complicated and time-consuming modification procedures. The as-prepared rGO sheets not only exhibit high reduction level and conductivity, but also can be well dispersed in many solvents. Of particular significance is that rGO sheets can be produced in large quantities. These advantages endow this proposed synthetic approach great potential applications in the construction of high-performance graphene-based devices at low cost, as demonstrated in our study of NO gas sensing.

A novel template-free approach to prepare nitrogen-doped hollow carbon microspheres with graphitic carbon shells (NHGCSs) was reported. The obtained NHGCSs by the direct pyrolysis of solid melamine–formaldehyde (MF) resin spheres exhibit excellent capacitance performance. The specific capacitance reaches 306 F g⁻¹ at a current density of 0.1 A g⁻¹ (in 2 M H₂SO₄), and remains as high as 230 F g⁻¹ even at a high current density of 3 A g⁻¹, which indicates the optimistic prospects for using NHGCSs as supercapacitor electrode materials.