Palladium nanoparticles supported on nitrogen-doped carbon nanofibers: Synthesis, microstructure, catalytic properties, and self-sustained oscillation phenomena in carbon monoxide oxidation

The oxidation of CO over Pd nanoparticles supported on carbon nanofibers (CNFs) and N-doped carbon nanofibers (N-CNFs) has been studied. Investigation by scanning transmission electron microscopy together with electron energy-loss spectroscopy revealed that Pd nanoparticles are located on the N-CNFs surface patches that have a high concentration of N atoms. The N-doping of CNFs was shown to change the electric conductivity of N-CNFs and redox properties of Pd, which thus determines the self-oscillatory behavior of the catalysts during CO oxidation, the type of oscillations, and the conditions of their generation. Mechanisms that underlie the effect of N in N-CNFs on the electronic state of Pd as well as the occurrence of two types of oscillation mechanisms - the known redox mechanism and the mechanism related to Pd intercalation into graphene layers - are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.