Low-Cost Sulfonated Phthalocyanines-Derived Hierarchical Porous Co-Cu-N-S-Doped Carbons for Efficient Oxygen Electroreduction

Abstract

Low-cost commercial sulfonated phthalocyanines were converted into a series of porous multi-doped carbons with Co/Cu and N/S heteroatoms (Co-Cu-N-S-Cs). The water-soluble sulfonated copper (II) phthalocyanines and sulfonated cobalt (II) phthalocyanines could be coated on commercial silica nano-spheres with the interlinking of the acidized chitosan polymers, and the direct pyrolysis of such composites produced hierarchical porous carbons with abundant multi-doped sites. The Co-Cu-N-S-Cs exhibited the efficient electro-catalytic performance for oxygen reduction reaction (ORR) in both alkaline and acidic electrolytes. In particular, the ORR half-wave potential over Co-Cu-N-S-C-900 reached 0.85 V in 0.1 M KOH, 10 mV higher than Pt/C (20 wt%) electro-catalysts. Co-Cu-N-S-C-900 also demonstrated better stability and methanol-tolerance properties, in contrast to commercial Pt/C catalysts (JM, 20wt%). The mixed using of sulfonated Cu and Co phthalocyanine precursors help to balance the graphitization-related electron transportation and doping defects-related active site density in Co-Cu-N-S-C-900. These results indicated that low-cost and high-efficency multi-doped carbon-based electrocatalysts for ORR could be facile prepared using commercial sulfonated phthalocyanines. (C) The Author(s) 2018. Published by ECS.