Activating Nitrogen-doped Graphene Oxygen Reduction Electrocatalysts in Acidic Electrolytes using Hydrophobic Cavities and Proton-conductive Particles

Santosh K. Singh, Kotaro Takeyasu, Kaito Homma, Shigeharu Ito, Takashi Morinaga, Yuto Endo, Moeko Furukawa, Toshiyuki Mori, Hirohito Ogasawara, Junji Nakamura

Research output: Contribution to journalArticlepeer-review

Abstract

Although pyridinic-nitrogen (pyri-N) doped graphene is highly active for the oxygen reduction reaction (ORR) of fuel cells in alkaline media, the activity critically decreases under acidic conditions. We report on how to prevent the deactivation based on the mechanistic understanding that (Formula presented.) governs the ORR kinetics. First, we considered that the deactivation is due to the hydration of pyri-NH+, leading to a lower shift of the redox potential. Introducing the hydrophobic cavity prevented the hydration of pyri-NH+ but inhibited the proton transport. We then increased proton conductivity in the hydrophobic cavity by introducing SiO2 particles coated with ionic liquid polymer/Nafion® which kept the high onset potentials with an increased current density even in acidic media.

Original languageEnglish
Article numbere202212506
JournalAngewandte Chemie - International Edition
Volume61
Issue number51
DOIs
Publication statusPublished - Dec 19 2022
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

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