Herein, multi-core-shell structure Co/FeC@N-doped hollow carbon (Co/FeC@NHC) with tunable carbon shell thickness is well crafted by a novel and simple strategy. Novel core-shell structure consisting of polydopamine (PDA) shell with different thickness and bimetal-based metal-organic frameworks (MOFs) Co/Fe core with cubic morphology are first prepared, followed by a thermal and etching treatments to fabricate hollow composite materials composed of multiple Co/FeC cores evenly distributed in N-doped carbon shell. PDA acts as a carbon and nitrogen source simultaneously to form N-doped hollow carbon in this procedure. Creatively, the N-doped hollow carbon shell protects Co/FeC core and against the degradation, in addition to enhance the conductivity of Co/FeC@NHC. Through adjusting the PDA shell thickness simply, Co/FeC@NHC with tunable N-doped carbon shell thickness is well crafted. The Co/FeC@NHC-1 with the best electrocatalytic performance is obtained by optimizing the thickness of N-doped hollow carbon shell. The Co/FeC@NHC-1 exhibits the highest activity for the oxygen evolution reaction (OER) and outstanding stability and durability. Hence, this research may establish a promising path for the rational design of metals@carbon composite with controllable structure which can act as highly efficient electrocatalysts for (OER). (C) 2020 Elsevier Inc. All rights reserved.