1 College of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 2 Research Center for Analysis and Measurement, Kunming University of Science and Technology, Kunming 650093
During the process of the aniline polymerization, bivalent cobalt salt with different anionic groups such as (C2H3O2)22-, Cl22-, (NO3)22-, SO42- and C2O42- were added into the solution and then different polyaniline cobalt (PANI-Co) coordination polymer were obtained. Finally, Co-N-C catalysts were prepared through pyrolysis of PANI-Co coordination polymer. The morphology, structure, chemical composition and chemical valence of the Co-N-C catalysts were characterized by scanning electron microscopy (SEM), X-ray spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectra (Raman). The electrocatalytic activity of Co-N-C catalysts were tested by electrochemical method. The results showed that the cobalt salt anionic groups had little impact on the morphology of Co-N-C catalysts, but had a great influence on the composition and surface chemistry of Co-N-C catalysts, carbon structure, degree of graphitization and the valence of Co. The cobalt salt anionic groups could affect the electrocatalytic activity of Co-N-C catalysts. The catalytic activities decreased as (C2H3O2)22->Cl22->(NO3)22->SO42->C2O42-. The Co-N-C catalysts prepared by cobalt salt containing (C2H3O2)22- and Cl22- anions had higher ORR activity, which possibly due to the higher content of graphite nitrogen and pyridine nitrogen.
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