Synthesis, characterization, and electrocatalytic properties of a polypyrrole-composited Pd/C catalyst

Polypyrrole composition over carbon-supported palladium nanoparticles (Pd-PPy/C) is successfully performed as electrocatalysts for acid-based fuel cell. This approach demonstrates that PPy modification on a Pd surface remarkably suppresses the deactivation of Pd under acidic conditions. We attempted to determine the influence of PPy on the Pd surface with respect to stability. For this purpose, a potential cycling test and inductively coupled plasma mass spectrometry (ICP–MS) analysis are applied to this system to investigate how PPy affects Pd surface area loss by dissolution and particle growth/agglomeration. The electronic structure of the catalysts is also analyzed with X-ray absorption-near-edge spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS). The increase in stability upon PPy modification of Pd nanoparticles can be interpreted as a result of the redox properties of PPy polymer itself because the electronic interaction of Pd and PPy doesn’t reveal a shifting of the d-band center (ɛd). Consequently, our work may suggest that conjugated polymer-composited metal catalysts are good potential candidate in the development of efficient electrocatalysts because of the possibility of electrochemical role of the conjugated polymer.