Iron　and　nitrogen　co-doped　carbons　show　great　potential　for　high-performance　electrochemical　oxygen　reduction　reaction.　However,　the　rational　design　of　atomically　dispersed　iron　over　nitrogen-doped　carbons　with　activity　comparable　to　that　of　Pt-C　is　still　challenging.　Herein,　we　develop　a　new　approach　that　enables　the　direct　formation　of　intrinsically　nitrogen-functionalized　two-dimensional　sheet-like　carbons　containing　a　high　concentration　of　single　Fe　atoms.　This　strategy　only　involves　one-step　pyrolysis　of　both,　guanine　and　iron　nitrate,　without　using　any　guiding　agent　and　sacrificial　template.　The　electrochemistry　tests　demonstrate　an　excellent　ORR　performance　of　the　prepared　Fe-N-x-C　catalyst　with　a　half-wave　potential　of　0.85　V　and　a　limited　current　density　of　6.5　mA/cm(2)　in　alkaline　medium,　outperforming　the　commercial　Pt-C　and　most　of　previously　reported　Fe-N-x-C　catalysts.　We　believe　that　the　emergence　of　superior　ORR　performance　is　mostly　attributed　to　the　uniform　dispersion　of　single　Fe　atoms　at　the　molecular　level　and　the　formation　of　abundant　coordinated　Fe-N-x　sites.　In　addition,　the　high　surface　area,　optimal　porosity　and　defective　structure　(particularly　the　defects　at　the　edge)　of　the　two-dimensional　carbons　are　also　beneficial　for　the　improved　ORR　activity.