Controllable active sites and facile synthesis of cobalt nanoparticle embedded in nitrogen and sulfur co-doped carbon nanotubes as efficient bifunctional electrocatalysts for oxygen reduction and evolution reactions

Abstract

Abstract Development of efficient and promising bifunctional electrocatalysts for oxygen reduction and evolution reactions is desirable. Herein, cobalt nanoparticles embedded in nitrogen and sulfur co-doped carbon nanotubes (Co@NSCNT) were prepared by a facile pyrolytic treatment. The cobalt nanoparticles and co-doping of nitrogen and sulfur can improve the electron donor-acceptor characteristics of the carbon nanotubes and provide more active sites for catalytic oxygen reduction and evolution reactions. The prepared Co@NSCNT, annealed at 900 °C, showed excellent electrocatalytic performance and better durability than commercial platinum catalysts. Additionally, Co@NSCNT-900 catalysts exhibited comparable onset potentials and Tafel slopes to ruthenium oxide. Overall, Co@NSCNT showed high activity and improved durability for both oxygen evolution and reduction reactions.