▎ 摘　　要

Biomass-derived carbon dots (CDs) were prepared via a green one-step synthetic technique using cauliflower leaf wastes as natural carbon precursor. The as-prepared CDs were used to fabricate composites with reduced graphene oxide (RGO) via a one-step hydrothermal treatment. The electrochemical performance of the electrodes was investigated with variable GO to CD mass ratios. The RGO/CD composite with a 2:1 mass ratio (RC-21) exhibited high specific capacitance with maximum discharge capacitances of 278 F g(-1) and 227 F g(-1) at 0.2 A g(-1) and 2 mV s(-1), respectively, together with excellent capacitance retention of 60% when the current density increased from 0.2 to 100 A g(-1) and 63% with scan rate rise from 2 to 1000 mV s(-1), respectively. The results are discussed in terms of the composition, surface area, pore volume, electrical conductivity and proton diffusivity.