RESUMO
In this work, oxygen reduction reaction (ORR) electrocatalysts Fe/Ni bimetal and nitrogen co-doped porous carbon fibers (Fex/Niy-NPCF), derived from electrospun nanofiber, have been prepared. In order to optimize the ORR performance of one dimension (1D) catalysts, SiO2 were used as template to create the hierarchical porous structure. The morphology of Fex/Niy-NPCF was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). By adjusting the ratio of iron and nickel, the influence of the trace of secondary-metal doping in electrocatalyst on catalytic activity was deeply studied. The electrochemical measurements suggested that the trace of secondary-metal doping was good for increasing the half-wave potential of electrocatalyst. The optimized Fe28/Ni2-NPCF exhibited an excellent catalytic activity with an onset potential of 0.96â¯V and a half-wave potential of 0.88â¯V, which are comparable to that of the benchmark 20â¯wt% Pt/C. This excellent catalytic performance was derived from secondary-metal doping and abundant pore structure.
RESUMO
Biomass derived porous carbon was wildly used in non-precious metal carbon based electrocatalysts for ORR due to its low cost and sustainability. Here, we develop a facile route to prepare Co/N doped hemp derived highly porous carbon (Co/NHPC) as ORR electrocatalyst. The prepared Co/NHPC-90 possess 3D hierarchically porous nanostructure with high specific surface areas (1251â¯m2 g-1) and large pore volumes (0.99â¯cm3 g-1) due to the chemical activation of NaHCO3, which is benefit for the mass/electron transfer and exposure of active sites. In addition, melamine and cobalt nitrate were selected as nitrogen and metal source respectively to enrich the density of active sites. Thus, Co/NHPC-90 exhibits excellent ORR electrocatalytic performance with high half-wave potential (0.826â¯V), superior catalytic stability and tolerance to methanol.