Palladium nanoparticles supported on phosphorus-doped carbon for ethanol electro-oxidation in alkaline media

摘要

Palladium nanoparticles supported on carbon Vulcan XC72 (Pd/C) and on phosphorus-doped carbon (Pd/P-C) were prepared by an alcohol reduction process. X-ray diffractograms of Pd/C and Pd/P-C showed the typical face-centered cubic (fcc) structure of Pd. The crystallite sizes of Pd fcc phase were around 8 nm for both samples. X-ray photoelectron spectroscopy revealed to Pd/C and Pd/P-C that Pd was found predominantly in the metallic state and to Pd/P-C, the presence of P increases the amount of oxygen on the electrocatalyst surface. The activity and stability of the electrocatalyts for ethanol electro-oxidation in alkaline medium was investigated by cyclic voltammetry and chronoamperometry experiments. The peak current density on Pd/P-C was 50% higher than on Pd/C, while the current density measured after 30 min at - 0.35 V vs. Hg/HgO was 65% higher on Pd/P-C than on Pd/C. The enhancement of the catalytic activity of Pd/P-C electrocatalyst might be related to the presence of higher amounts of oxygen species on the surface, which could contribute to the oxidation of intermediates formed during ethanol electro-oxidation process.