Heavily nitrogen doped chemically exfoliated graphene by flash heating

Heteroatom doping can enhance the electrochemical properties of graphene. However, unstable CN bonding at high temperature limits the concentration of nitrogen dopants. Intense pulsed light (IPL) was used to prepare heavily nitrogen-doped reduced graphene oxide (NrGO). Unlike general heating methods like thermal annealing, IPL provides ultrafast direct heating and cooling in the graphene layers because they serve as the heating source after light absorption. As this heat originates from the photothermal effect of surface plasmons on the graphene layers, nitrogen precursors are effectively decomposed. The fast cooling also generates a corrugated graphene structure with high specific surface area owing to thermal quenching. The electronic and structural properties of flash-heated NrGO (FH-NrGO) were investigated by X-ray photoelectron spectroscopy, Raman spectroscopy, and ultraviolet photoelectron spectroscopy, which revealed a high total nitrogen content of 26 at.% after flash heating at 1500 °C. Moreover, the nitrogen content could be varied by controlling the irradiation energy, and the electrochemical performance of FH-NrGO was better than that of NrGO prepared by general heating. Therefore, flash heating by IPL can be used to produce heavily nitrogen-doped graphene with superior electrochemical performance as an anode material for energy-storage devices.