Stepwise Fabrication of Co-Embedded Porous Multichannel Carbon Nanofibers for High-Efficiency Oxygen Reduction
HighlightsAn interconnected structure is developed by evaporation of zinc species using a ZnCo2O4 precursor as the cobalt resource, enabling communications between channels as well as homogeneous loading of active sites.A shell structure of Co3O4 is formed on the surface of a zero-valent Co0 core during a stepwise carbothermic reduction of ZnCo2O4.The Co-embedded multichannel carbon nanofibers exhibit not only a superior half-wave potential, but also an excellent durability compared to those of the commercial 30% Pt/C.AbstractA novel nonprecious metal material consisting of Co-embedded porous interconnected multichannel carbon nanofibers (Co/IMCCNFs) was rationally designed for oxygen reduction reaction (ORR) electrocatalysis. In the synthesis, ZnCo2O4 was employed to form interconnected mesoporous channels and provide highly active Co3O4/Co core–shell nanoparticle-based sites for the ORR. The IMC structure with a large synergistic effect of the N and Co active sites provided fast ORR electrocatalysis kinetics. The Co/IMCCNFs exhibited a high half-wave potential of 0.82 V (vs. reversible hydrogen electrode) and excellent stability with a current retention up to 88% after 12,000 cycles in a current–time test, which is only 55% for 30 wt% Pt/C.