Among the various synthetic strategies explored in the literature, thermal annealing is presumed as efficient method for the synthesis of heteroatom doped graphene as it involves the high temperature treatment of GO to regenerate the sp 2 hybridized carbon framework and the heteroatom doping over graphene network was achieved using the appropriate dopants. It is apparent that the annealing temperature has played a vital role in the specificity of N-doping over graphene lattice. In general, the temperature range (500-600 °C) is the optimum range for the stability of different kinds of nitrogen . It was reported that if the annealing temperature rises, then the content of pyridinic and quaternary nitrogen enhances while that of pyrrolic nitrogen diminishes and the appropriate XPS profiles are displayed in Fig. . When the GO was thermal annealed with NH3 at 550 °C, then pyridinic nitrogen is exclusively formed . The admixture of both pyridinic and graphitic nitrogens are formed if the thermal annealing of GO with NH3 was performed at 850 °C. Both graphitic and pyridinic nitrogen were found to be exclusively formed when the thermal annealing of GO with NH3 was carried out at temperature at 1000 °C. The formation of N-doped graphene with different states of nitrogen from GO via pyrolysis with variety of precursors is schematically depicted in Fig. .