MOF-derived N-doped carbon coated Co/RGO composites with enhanced electrocatalytic activity for oxygen reduction reaction

During recent years, increasing demand of new, clean, and renewable energy resources has stimulated wide study on exploitation of non-platinum-group cathode catalysts for oxygen reduction reaction (ORR). Here, a series of nitrogen-doped carbon coated Co nanoparticle supported on reduced graphene oxide (Co@NC/RGO) were prepared by growth of ZIF-67 on GO with subsequent carbonation. The influence of incorporating dose of GO on the catalyst structure and activity was studied. The phase structure, morphology, element distribution, element composition, specific surface area, and pore-size distribution were characterized by various characterization techniques. The highest catalytic performance is achieved when the adding proportion of GO is 2.6% with the onset potential of 0.96 V and half-wave potential of 0.82 V. The introduction of RGO not only improves the electronic conductivity but also accelerates charge transfer. The special porous structure makes it have high specific surface area (313.7 m(2) g(-1)) and large pore size (12.6 nm). The contents of pyridinic-N (53.4%) and graphitic-N (19.3%) in Co@NC/RGO-2.6 are higher than those in Co@NC (50.2% and 10.3%). Co@NC/RGO-2.6 exhibits much higher durability than commercial Pt/C. The ORR mechanism on the home-made catalyst is similar to that on Pt/C.