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Sulfur‐Doped Carbon Aerogel as a Metal‐Free Oxygen Reduction Catalyst
Author(s) -
Seredych Mykola,
László Krisztina,
Bandosz Teresa J.
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500192
Subject(s) - aerogel , catalysis , sulfur , heteroatom , inorganic chemistry , resorcinol , chemistry , electrolyte , carbon fibers , adsorption , electrocatalyst , oxygen , methanol , metal , dispersion (optics) , materials science , electrochemistry , organic chemistry , electrode , nanotechnology , physics , composite number , optics , composite material , ring (chemistry)
Resorcinol‐formaldehyde‐based carbon aerogels were modified by treatment with H 2 S at 650 and 800 °C and used as catalysts for the oxygen reduction reaction (ORR) in an alkaline medium. On the material treated at high temperature, the electron transfer number was close to 4 e − and the onset potential for the ORR was shifted to a more positive value. An excellent tolerance to methanol crossover was also detected. The treatment resulted in sulfur doping in the form of thermally stable thiophenic compounds, which increased the surface hydrophobicity. This sulfur leads to a positive charge on the carbon atoms, which are the reaction sites. The hydrophobicity of the surface enhances the withdrawal of O 2 from the electrolyte and its adsorption on the surface. The specific micro‐/mesoporosity contributes to a high dispersion of sulfur heteroatoms on the surface and to the accessibility of the surface sites to the electrolyte and thus to oxygen dissolved in water.