▎ 摘　　要

Since the successful exfoliation of graphene was reported, the emergence of two-dimensional (2D) materials has inspired the construction of 2D/2D heterostructures for catalytic applications. In this work, a novel strategy is proposed for activity modulation in oxygen reduction electrocatalysis through constructing a heterojunction, which consists of CoN4 embedded graphene and B doped graphene with B concentrations of 3.13 at% and 6.25 at %, termed as BG/B1 and BG/B2 for convenience, respectively. The theoretical results reveal that the B doped graphene alleviates OH poisoning of CoN4 moiety and thereby promotes the activity improvement. As the main indicator of catalytic activity, the overpotential eta values are 0.46 V for BG/B1 and 0.38 V for BG/B2, respectively, which are comparable to the benchmark Pt(111). The underlying regulation mechanism involves the electron redistribution, wherein the electron-deficient B dopant causes electron depletion of the CoN4 embedded gra-phene. More intriguingly, the activity improvement caused by vertical electron transfer is observed for the bi-layers with FeN4 moiety. The similarity between CoN4 and FeN4 implies that the electron-mediated mechanism via the 2D/2D coupling might be a universal strategy for material design. Therefore, the proposed graphene-based heterojunction provides a novel insight into activity modulation in electrocatalysis field.