3D N, S-co-doped carbon nanotubes/graphene/MnS ternary hybrid derived from Hummers' method for highly efficient oxygen reduction reaction

Abstract Designing and preparing oxygen reduction reaction (ORR) catalysts with low cost, high activity and strong stability play a crucial function in the application of fuel cells and metal-air batteries. In this work, we use pristine graphite and carbon nanotubes (CNT) mixture as initial carbon source, and for the first time successfully prepare N, S-co-doped carbon nanotubes/graphene/MnS ternary hybrid (NSCNT/NSG/MnS) by modified Hummers' method followed by a pyrolysis process. The morphology, structure, composition and ORR performance of the obtained sample are measured by scanning electron microscope, X-ray diffraction and lots of other techniques. The results show that the successful synthesis of NSCNT/NSG/MnS is achieved by the combination of effective exploitation of residual Mn and S species and strong reducibility of carbon under high temperature. Besides, we find that the resultant NSCNT/NSG/MnS can not only effectively stabilize and disperse MnS nanoparticles, but also possess large specific surface area, high N content and unique 3D architecture. Compared to other counterparts, the obtained 3D NSCNT/NSG/MnS exhibits superior ORR performance (the onset potential moves positively to 1.00 V; limiting-current density achieves 4.93 mA/cm2; ORR electron transfer number is close to four), which is proven to approach that of commercial Pt/C catalyst.