Boosting oxygen reduction catalysis with N, F, and S tri-doped porous graphene: Tertiary N-precursors regulates the constitution of catalytic active sites

Abstract

Single or binary heteroatom-doped carbons, as excellent electrocatalysts towards oxygen reduction reaction (ORR), are widely investigated in recent years. However, due to difficulties in choosing suitable precursors, lacking of design principles, and controlling beneficial constitutions of heteroatoms, the development of ternary or multi-doped carbons still remains a great challenge. Herein, with N as the primary dopant, we also dope F and S atoms into graphene carbon matrix to offer promotional effect using a novel tertiary N-precursors inspired strategy. Composition and performance studies demonstrate that introducing the secondary and tertiary N-precursors could increase the configurations of active sites, thus improving the catalyst's ORR activity. Remarkably, after reaching further doping with F, S atoms, the obtained N, F, and S tri-doped porous graphene (FN3SG) shows greatly enhanced ORR performance with positive onset potential of 0.988 V and half-wave potential of 0.803 V vs. RHE comparable to the Pt/C in alkaline media, which is mainly attributed to its more introduced active sites and porous architectures. Furthermore, the as-prepared FN3SG catalyst also exhibits better methanol tolerance and higher stability. This facile but general synthesis strategy can be extended to design and prepare of other carbon-based electrocatalysts with high-performance catalytic activities.