Novel in-situ P-doped metal-organic frameworks derived cobalt and heteroatoms co-doped carbon matrix as high-efficient electrocatalysts

Abstract

Metal organic frameworks (MOFs) are considered as ideal templates for the synthesis of metal-heteroatom co-doped carbon materials. However, the tedious heteroatoms doping pathways hinders the maximizing of catalytic performances. Herein, we synthesize a series of high-efficient Co and N, P heteroatoms co-doped carbon-based composites by first constructing a novel in-situ P-doped MOF with novel larger N, P-containing ligands and 2-methylimidazole as mixed ligands, and then calcining these MOFs at high temperature. During the pyrolysis process, the generated gases derived from the thermal decomposition of organic ligands are liberated from inner of P-ZIF materials to make the Co–Co2P@NC-P catalysts become loose and porous. When being used as electrode materials, the optimal Co–Co2P@NC-P3-700 catalyst exhibits excellent ORR and OER activity, the ORR performance is superior to the Pt/C catalysts, and the OER performance can be comparable with the commercial RuO2 catalyst. Moreover, when applied in the assembled primary Zn-air battery, the performances of Co–Co2P@NC-P3-700 catalyst can outperform the commercial Pt/C catalysts, exhibiting a high peak power density, specific capacity and a long-term stability. Furthermore, the catalytic active sites of catalysts are carefully investigated in this work.