Open AccessOctahedral spinel electrocatalysts for alkaline fuel cells
Author(s) -
Yao Yang,
Yin Xiong,
Megan E. Holtz,
Xinran Feng,
Rui Zeng,
Gary Chen,
Francis J. DiSalvo,
David A. Muller,
Héctor D. Abruña
Publication year - 2019
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.1906570116
Subject(s) - spinel , octahedron , fuel cells , materials science , alkaline battery , chemical engineering , inorganic chemistry , chemistry , metallurgy , crystallography , crystal structure , engineering , electrode , electrolyte
Significance We present a systematic study of a family of 15 types of octahedral spinel electrocatalysts for the oxygen reduction reaction (ORR) in alkaline fuel cells. Three specific candidates, MnCo2 O4 /C, CoMn2 O4 /C, and CoFe2 O4 /C, exhibited very promising ORR activity. In particular, CoMn2 O4 /C could rival the ORR activity and selectivity of Pt/C. Such performance was ascribed to a partial charge transfer between Co and Mn. The most active, MnCo2 O4 /C, exhibited a unique Co–Mn core–shell structure with heterogeneous valence states, which were probed at the single-nanoparticle level using scanning transmission and high-energy-resolution electron-loss near-edge structure. We believe that our approach, of combining advanced electron microscopy and spectroscopy, will enable the design of highly active nanocatalysts with unprecedented atomic-scale precision.
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