Abstract Three‐dimensional porous graphene (3D‐PG) has attracted much attention due to its excellent electrochemical performance. Chemical reduction is one of common methods for preparing porous graphene. In order to develop a green and facile method for preparing three‐dimensional porous graphene, in this paper, 3D‐PG was fabricated by reduction of graphene oxide (GO) with ascorbic acid (AA) as reductant in hydrothermal condition based on non‐toxic, non‐flammable and mild reducing performance of ascorbic acid. It was found that the size and distribution of pores could be controlled by the reduction time and the concentration of AA in the solution. The pore sizes in R0, R1 and R2 were in the range of 0.5–1 μm, 1–1.5 μm, and 1.5–3 μm, respectively. It was found that the average pore size and volume increased along with the amount of reductants. Under optimal conditions – a reaction time of 20 h and a ratio of GO to AA=1 : 1 – the CV area of the so‐obtained sample R1‐20 at 100 mV was 0.06 and the specific capacitance of the 3D‐PG electrode reaches 153.5 F ⋅ g−1, which is suitable for use in supercapacitors.
