LAUSR

Abstract It is proved that Fe and N complex modified carbon (Fe-Nx-C) is a fantastic electrocatalyst for oxygen reduction reaction. However, it is still challenging to obtain it due to the easy tendency of Fe-based nanoparticles formation. Basically, the zeolitic imidazolate framework-67/8 are employed to fabricate the Fe-Nx-C electrocatalyst. Herein, another type of metal organic framework rich in N and S is employed to accommodate the Fe complex to firstly construct the Fe-Nx and N, S co-functionalized porous carbon (FeNSC) electrocatalysts through the site isolation strategy. The characterizations indicate that the optimal electrocatalyst has various active sites (highly active Fe-Nx moieties, N and S co-doping), high surface area and well-defined channels. Also, the role of Fe-Nx is highlighted by the contrast samples and the toxication experiment. Thus, the optimal FeNSC presents exceptional performance for ORR in the term of a half-wave potential (E1/2) of 0.892 V, which 52 mV lower than that of commercial Pt/C. Besides, high kinetic current density (Jk) of 12.8 mA cm−2 at 0.85 V and the small Tafel slope of 65 mV dec−1 reveal the fast kinetic. Importantly, the catalyst displays a half-wave potential of 0.732 V and small Tafel slope of 45 mV dec−1 in acidic medium, indicative of satisfying performance.