Enhancing activity and durability of Pd nanoparticle electrocatalyst by ceria undercoating on carbon support

One-pot synthesis of porous Pd-polypyrrole/nitrogen-doped graphene nanocomposite as highly efficient catalyst for electrooxidation of alcohols

Herein, a ternary-nanocomposite Pd-polypyrrole/nitrogen-doped graphene (Pd-PPy/NGE) has been prepared facilely by the one-pot method. In simple terms, PPy was in-situ polymerized on the surface of NGE with PdCl₄^2- as the oxidant, and simultaneously Pd nanopaticles were loaded on the surface of PPy or embedded in PPy particles. The obtained Pd-PPy/NGE nanocomposite exhibits promising electrocatalytic properties toward the oxidation reaction of alcohols in alkaline medium. Especially, the optimized Pd-PPy/NGE (1:50) catalyst possesses mass activity of 2176.7, 1192.7 and 498.9 mA mg_Pd^-1 toward ethylene glycol, methanol and ethanol electrooxidation, respectively, which are 4.3, 6.7 and 2.9 times of those for commercial Pd/C catalyst. Moreover, the Pd-PPy/NGE (1:50) also shows higher anti-poisoning ability and operating stability than the Pd/C catalyst. The promising electrocatalytic performance of the Pd-PPy/NGE (1:50) for alcohols oxidation can be ascribed to the well dispersion of Pd nanoparticles, the porous and stable three dimentional structure of the composite, and the synergistic effect between different components. The structural randomness of the conducting polymer and the potential synergistic effect between the metal nanoparticles and various supports would provide broad development space for these composites as electrocatalysts in direct alcohol fuel cell.