Palladium nanoparticles loaded on nitrogen and boron dual-doped single-wall carbon nanohorns with high electrocatalytic activity in the oxygen reduction reaction.

Palladium nanoparticles with a diameter of 2-4 nm supported on nitrogen and boron dual-doped single-wall carbon nanohorns (Pd-NBCNHs) are synthesized via a one-step method and their electrocatalytic activities are investigated for the oxygen reduction reaction (ORR) in alkaline media. The electrochemical results demonstrate that the oxygen reduction peak potential of Pd-NBCNHs is similar to that of commercial 20% Pt-C. Furthermore, Pd-NBCNHs show a more positive half-wave potential than 20% Pt-C and display better long-term stability and resistance to methanol than 20% Pt-C, which is attributed to the synergetic effect of the Pd nanoparticles and NBCNHs. As NBCNHs have abundant pyrrolic nitrogen, charged sites and defective structures, they not only act as a carrier, but also provide the active sites for oxygen adsorption during the oxygen reduction reaction process. The outstanding electrochemical performance makes Pd-NBCNHs promising to be applied in fuel cells.