Surfactant-assisted Fe-anchored and N-doped ultrathin graphene nanosheets for enhanced electrocatalytic oxygen reduction

Abstract

Exploration of tremendous electrocatalysts for oxygen reduction reaction (ORR) as promising alternatives is urgent in various electrochemical applications. As a result, one catalyst of homogeneously dispersed Fe, N sites anchored on two-dimensional (2D) ultrathin graphene nanosheets (Fe-N@C) is rationally designed and synthesized via a surfactant-assisted pyrolysis approach. Water-soluble F127 surfactant facilitates the uniform dispersion of Fe and restrains the aggregation of Fe-based particles during pyrolysis treatment, which promotes the formation of plentiful FeNx species. The 2D ultrathin structure is beneficial to expose more FeNx and make the most use of these active sites. Therefore, the developed Fe-N@C catalyst demonstrates enhanced catalytic properties in alkaline media with an approximate 4e− pathway and more positive half-wave potential (E1/2, 0.85 V), which is plus 0.04 V than commercial 20 % Pt/C catalyst. Besides, the target catalyst also exhibits superb poison resistance and long-term stability. This work presents a practical direction for the fabrication of other high-efficient catalysts and a new insight into ORR.