High-performance non-noble electrocatalysts for oxygen reduction reaction( ORR) are the prerequisite for large-scale utilization of fuel cells. Herein, at ype of sandwiched-liken on-noblee lectrocatalyst with highly dispersed FeN x active sites embedded in ah ierarchically porous carbon/graphene heterostructure was fabricated using a bottom-up strategy.T he in situ ion substitution of Fe 3 + in a nitrogen-containing MOF (ZIF-8) allows the Fe-heteroatoms to be uniformly distributed in the MOF precursor,a nd the assembly of Fe-doped ZIF-8 nano-crystals with grapheneoxide and in situ reduction of graphene-oxide afford as andwiched-like Fe-doped ZIF-8/graphene heterostructure. This type of heterostructuree nables simultaneous optimization of FeN x active sites, architecture and interfacep roperties for obtaining an electron-catalyst after ao ne-step carbonization. The synergistic effect of these factorsr ender the resulting catalysts with excellent ORR activities. The half-wave potential of 0.88 Vv s. RHE outperforms most of the none-noble metal catalysta nd is comparable with the commercial Pt/C (20 wt %) catalyst. Apart from the high activity,t his catalyst exhibits excellent durability and good methanol-tolerance. Detailed investigations demonstrate that am oderatec ontent of Fe dopantsc an effectively increaset he intrinsic activities, andt he hybridization of graphene can enhancet he reaction kinetics of ORR. The strategy proposed in this work gives an inspiration towards developing efficient noblemetal-free electrocatalysts for ORR.[a] Dr.