Displacement preparation-induced effects on structure of Ag-Pd nanobrushes for catalyzing oxygen reduction

Ag-Pd nanobrushes containing Ag-rich material, a thick Pd shell, or a thin Pd shell were successfully prepared using galvanic displacement. After 10 min of displacement, Ag-rich nanobrushes were formed. With an increase in displacement time to 30 min or 50 min, nanobrushes covered with a Pd thick-film or Pd thin-film were prepared, respectively. In an application using an oxygen reduction reaction catalyst in a 1 M NaOH electrolyte, the electron numbers involved (at -0.15 V vs. Ag/AgCl) for the nanobrushes containing Ag-rich Ag-Pd, Pd thick-shell, and Pd thin-shell were 1.65, 2.37, and 3.76, respectively. Faster kinetics of the nanobrushes with a Pd thin-shell was observed. In the activation-control region, the mass activity (at -0.05 V) of these nanobrushes was 0.13 mA mg(-1), which was higher than 0.07 mA mg(-1), the mass activity of Pd nanoparticles. (C) 2013 Elsevier B.V. All rights reserved.