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Impact of Surface Functionalization on the Intrinsic Properties of the Resulting Fe–N–C Catalysts for Fuel Cell Applications
Author(s) -
Kübler Markus,
Wagner Stephan,
Jurzinsky Tilman,
Paul Stephen,
Weidler Natascha,
Gomez Villa Eduardo D.,
Cremers Carsten,
Kramm Ulrike I.
Publication year - 2020
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.202000433
Subject(s) - surface modification , catalysis , x ray photoelectron spectroscopy , chemistry , chemical engineering , carbon nanotube , electrochemistry , selectivity , sorption , materials science , electrode , analytical chemistry (journal) , inorganic chemistry , nanotechnology , organic chemistry , engineering , adsorption
Herein, Fe–N–C catalysts are prepared from surface functionalized carbon nanotubes (CNTs) in combination with iron acetate and phenanthroline. An improved performance and structural composition is obtained by surface functionalization of the CNTs with indazole or pyridine. Catalyst composition and morphology are characterized by transmission electron microscopy, N 2 sorption, photoelectron spectroscopy, and 57 Fe transmission Mössbauer spectroscopy. However, activity and selectivity toward oxygen reduction reaction are determined from rotating ring disc electrode (RRDE) experiments. The durability and stability are evaluated by accelerated stress tests (0.0–1.2 V) and differential electrochemical mass spectroscopy (DEMS), respectively. It is shown that surface functionalization with indazole enables the direct attachment of FeN 4 centers to CNTs so that no impurity species are detected and a high activity is achieved, that can be attributed to an improved turnover frequency and higher mass‐based site density. Even more striking is the excellent durability and stability of the realized catalyst. While these trends are well pronounced in RRDE and DEMS, challenges in the preparation of membrane electrode assemblies make the trend not as obvious in fuel cells (FCs).