Metal-support interaction in platinum and palladium nanoparticles loaded on nitrogen-doped mesoporous carbon for oxygen reduction reaction.

Mesoporous carbons are highly porous materials, which show large surface area, chemical inertness and electrochemical performances superior to traditional carbon material. In this study, we report the preparation of nitrogen-doped and undoped mesoporous carbons by an optimized hard template procedure employing silica as template, sucrose and ammonia as carbon and nitrogen source, respectively. Surface area measurements assert a value of 900 and 600 m(2) g(-1) for the best doped and undoped samples, respectively.

Palladium nanoparticles supported on nitrogen-doped HOPG: a surface science and electrochemical study.

We have investigated by photoemission spectroscopy and scanning tunnelling microscopy what are the chemical and structural changes induced by nitrogen ion implantation (500 eV) on highly oriented pyrolytic graphite and how the defects induced by this process modify the growth and thermal stability of palladium nanoparticles, deposited in situ by physical vapour deposition. Since nitrogen derived defects are mostly buried below the surface, they are not accessible for a chemical interaction with metal nanoparticles; however, the amorphization induced by the ion beam in the outermost layers of the substrate beneficially affects the metal morphology, limiting the size of the nanoparticles and improving their thermal stability. The supported nanoparticles have been tested towards the oxygen reduction reaction indicating that the electrochemical activity does not depend significantly on the ion implantation, but mostly on the amount of palladium.