Sheet-like carbon-nitrogen (CN x )/graphene composites with a high content of nitrogen (x  0.15) was prepared by the carbonization of polypyrrole (PPy)/reduced-graphene-oxide (rGO) composite at 600-800°C. We used rGO instead of graphene oxide (GO) sheets as a template and a substrate to immobilize PPy since the PPy/GO composite agglomerates easily because of the dehydration of excess oxygen-containing groups on the GO sheets during the drying process. The dried PPy/rGO intermediate and its derived CN x /graphene products retain their high dispersion and loose-powder features. The as-prepared CN x /graphene composites have a total nitrogen content of about 10 at% and their nitrogen state is mainly of pyridinic and graphitic type. CN x /graphene composites exhibit excellent performance for the oxygen reduction reaction (ORR) in terms of electrocatalytic activity, stability and immunity towards methanol crossover and CO poisoning, suggesting their potential as metal-free electrocatalysts for the ORR. Low temperature fuel cells are a high-efficiency and environment-friendly energy supply for future transport and portable applications [1,2]. However, despite the great efforts worldwide over the past few decades their wide application in daily life is still a challenge because of the scare resources, high cost and durability issues for the current commercial Pt/C catalysts, especially for cathodes where the oxygen reduction reaction (ORR) is kinetically slow [3][4][5]. Therefore, research into non-precious metals or even metal-free catalysts with high ORR activity and durability is absolutely crucial for the development of fuel cells. Currently, it is widely accepted that nitrogen-containing carbon including macrocycle molecules [6][7][8], polymers [4,9] and nanomaterials [10][11][12][13][14][15][16][17][18][19] are a type of important building block for the preparation of Pt-substituted catalysts.Iron-or cobalt-doped carbon-nitrogen (CN x ) compounds have comparable activity to Pt/C catalysts in acidic systems [4,7,9,20]. Polypyrrole modified carbon-supported cobalt hydroxide can act as cathode and anode catalysts in direct borohydride fuel cells [21,22]. Recent promising results involving metal-free PEDOT [5] and nitrogen-doped carbon nanotubes (NCNTs) [14][15][16][17][18][19] have been reported for alkaline systems giving excellent electrocatalytic activity, stability and immunity towards methanol crossover and CO poisoning. Particularly, NCNTs have attracted extensive interest because of their large surface area, good thermal and chemical stability as well as high electrical conductivity [14][15][16][17][18][19]. It has been revealed that increasing the nitrogen content and the number of defects in NCNT enhances its electrocatalytic activity toward the ORR [11,16]. In addition to one-dimensional CNTs, the emergence of graphene has opened up a new field in terms of research into two-dimensional (2D)