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Start Over Author "Jun-ichi Ozaki" Journal ecs meeting abstracts
10 results on '"Jun-ichi Ozaki"'

6. Electrochemical Oxygen Reduction on Carbon Nitride

Author

Shigeki Kuroki, Masa-aki Kakimoto, Nazrul Islam, Jun-ichi Ozaki, Seizo Miyata, Yuta Nabae, and Stephen Matthew Lyth

Subjects
chemistry.chemical_compound, Materials science, Chemical engineering, chemistry, Electrochemistry, Carbon nitride, Oxygen reduction, Electrochemical reduction of carbon dioxide
Abstract

Electrochemical oxygen reduction via non-precious, Fe-macrocycle-derived catalysts has potential to reduce the cost and increase acceptance of hydrogen-powered polymer electrolyte membrane fuel cells. However since these materials are a complex mixture of carbon, nitrogen and iron, the nature of the active site is still much debated. By using carbon nitride as an ideal, nitrogen-rich, iron-free catalyst we shed light on the role of carbon-nitrogen bonding in electrochemical oxygen reduction. Carbon nitride was synthesized on a carbon black support via a simple solvothermal process. The resulting material was pyrolyzed and characterized via a variety of techniques. Electrochemical testing revealed that carbon nitride pyrolyzed at 1000åC displayed the best oxygen reduction activity, with an onset potential of 0.90V and a low selectivity to H2O2 formation, indicating a 4-electron oxygen reduction pathway. The enhanced activity is attributed to enriched quaternary nitrogen in the material at this temperature, as confirmed by X-ray photoelectron spectroscopy.

Published
2010
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9. The Role of Fe in the Preparation of Carbon Alloy Cathode Catalysts

Author

Seizo Miyata, Masa Aki Kakimoto, Shogo Moriya, Yuta Nabae, Shigeki Kuroki, Katsuyuki Matsubayashi, Michal Malon, Jun-ichi Ozaki, Nazrul Islam, and Stephen Matthew Lyth

Subjects
Materials science, Metallurgy, chemistry.chemical_element, Carbon alloy, Nitrogen, Cathode, Catalysis, law.invention, chemistry.chemical_compound, chemistry, Elemental analysis, law, Phthalocyanine, Moiety, Pyrolysis, Nuclear chemistry
Abstract

Pyrolysis of iron phthalocyanine/phenolic resin (FePc/PhRs) and phthtalocyanine/phenolic resin (Pc/PhRs) was studied to clarify the effect of Fe during the preparation of carbon alloy cathode catalysts. FePc/PhRs pyrolyzed at 600° showed the best electrocatalytic activity for oxygen reduction. CHN elemental analysis suggests that the catalysts with higher nitrogen content tend to show better catalytic activities. The results of TG/DTA/MS and IR suggest that Fe increases the nitrogen content of the catalysts by enhancing the interaction of phthalocyanine moiety and phenolic resin.

Published
2009
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