Oxygen reduction activity of N-doped carbon-based films prepared by pulsed laser deposition

Hakoda, Teruyuki; Yamamoto, Shunya; Kawaguchi, Kazuhiro; Yamaki, Tetsuya; Kobayashi, Tomohiro*; Yoshikawa, Masahito

Carbon-based films having nitrogen species on their surface were prepared on a glassy-carbon (GC) substrate as a non-platinum cathode catalyst for polymer electrolyte fuel cells by depositing cobalt and carbon in the presence of N gas using a pulse laser deposition method and then removing metal Co by HCl-washing treatment. The oxygen reduction reaction (ORR) activity was electrochemically determined using a rotating disk electrode system where the film samples on the GC substrate were replaceable. The ORR activity increased with elevating temperature of the GC substrate during the deposition. A carbon-based film prepared at 600C in the presence of 66.7 Pa N showed the highest ORR activity among the tested samples; its ORR potential was 0.66 V (vs. NHE). This film was composed of amorphous carbons doped with pyridine-type nitrogen atoms on its surface.