Synthesis of nitrogen-doped graphene driven from photothermal decomposition of ammonium bicarbonate and its application in supercapacitors

Abstract

In this work, nitrogen-doped graphene is achieved in a short time at low temperature by UV light radiation which induces thermal decomposition of ammonium bicarbonate (NH4HCO3) to release NH3 as nitrogen source. XRD and XPS results confirm that the most of oxygen-containing functional groups are removed from graphene oxide after photoreduction and nitrogen doping, and thus graphene oxide was reduced to form N-doped graphene. The N content of the obtained graphene is 2.91 at.%. The SEM images show that the graphene film on Ni foam is composed of spherical graphene nanoparticles, making it easy to adsorb more ions to form electric double-layer capacitance effect and increase the specific capacitance. As expected, the specific capacitance of UV assisted N-doped graphene is as high as 328.85 F g−1 at 0.5 A g−1, which is larger than that of graphene without nitrogen doping (261.13 F g−1 at 0.5 A g−1). Meanwhile, N-doped graphene shows good rate performance and cycle stability (capacitance retention rate: 96.1 % after 10, 000 cycles). This work shows the excellent supercapacitive performance of N-doped graphene, and also provides a simple and environmentally friendly method for rapid reduction and nitrogen doping of graphene oxide to prepare high-performance graphene.