TY - JOUR
T1 - Rate enhancements in structural transformations of Pt-Co and Pt-Ni bimetallic cathode catalysts in polymer electrolyte fuel cells studied by in situ time-resolved X-ray absorption fine structure
AU - Ishiguro, Nozomu
AU - Kityakarn, Sutasinee
AU - Sekizawa, Oki
AU - Uruga, Tomoya
AU - Sasabe, Takashi
AU - Nagasawa, Kensaku
AU - Yokoyama, Toshihiko
AU - Tada, Mizuki
PY - 2014/7/24
Y1 - 2014/7/24
N2 - In situ time-resolved X-ray absorption fine structure spectra of Pt/C, Pt3Co/C, and Pt3Ni/C cathode electrocatalysts in membrane electrode assemblies (catalyst loading: 0.5 mgmetal cm-2) were successfully measured every 100 ms for a voltage cycling process between 0.4 and 1.0 V. Systematic analysis of in situ time-resolved X-ray absorption near-edge structure and extended X-ray absorption fine structure spectra in the molecular scale revealed the structural kinetics of the Pt and Pt3M (M = Co, Ni) bimetallic cathode catalysts under polymer electrolyte fuel cell operating conditions, and the rate constants of Pt charging, Pt-O bond formation/breaking, and Pt-Pt bond breaking/re-formation relevant to the fuel cell performances were successfully determined. The addition of the 3d transition metals to Pt reduced the Pt oxidation state and significantly enhanced the reaction rates of Pt discharging, Pt-O bond breaking, and Pt-Pt bond re-forming in the reductive process from 1.0 to 0.4 V.
AB - In situ time-resolved X-ray absorption fine structure spectra of Pt/C, Pt3Co/C, and Pt3Ni/C cathode electrocatalysts in membrane electrode assemblies (catalyst loading: 0.5 mgmetal cm-2) were successfully measured every 100 ms for a voltage cycling process between 0.4 and 1.0 V. Systematic analysis of in situ time-resolved X-ray absorption near-edge structure and extended X-ray absorption fine structure spectra in the molecular scale revealed the structural kinetics of the Pt and Pt3M (M = Co, Ni) bimetallic cathode catalysts under polymer electrolyte fuel cell operating conditions, and the rate constants of Pt charging, Pt-O bond formation/breaking, and Pt-Pt bond breaking/re-formation relevant to the fuel cell performances were successfully determined. The addition of the 3d transition metals to Pt reduced the Pt oxidation state and significantly enhanced the reaction rates of Pt discharging, Pt-O bond breaking, and Pt-Pt bond re-forming in the reductive process from 1.0 to 0.4 V.
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U2 - 10.1021/jp504738p
DO - 10.1021/jp504738p
M3 - Article
AN - SCOPUS:84904977271
VL - 118
SP - 15874
EP - 15883
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 29
ER -