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Understanding adsorbate‐induced surface segregation in PtCo/C electrocatalyst
Author(s) -
Budiman Abdul Hamid,
Purwanto Widodo Wahyu,
Dewi Eniya Listiani,
Dalimi Rinaldy,
Hwang Bing Joe
Publication year - 2011
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.613
Subject(s) - x ray absorption spectroscopy , catalysis , electrocatalyst , materials science , population , particle size , chemical engineering , electrochemistry , nanoparticle , absorption spectroscopy , nanotechnology , chemistry , electrode , organic chemistry , physics , demography , quantum mechanics , sociology , engineering
The X‐ray diffraction (XRD) was used to study the effect of treatment on particle size and catalyst structure of PtCo/C electrocatalysts. The XRD showed the grain sizes of N 2 ‐treated electrocatalysts increase with temperature treatment, while those treated with CO remain the same. The X‐ray absorption spectroscopy (XAS) was used to study the changes in atomic distribution, extent of alloying as well as the surface population of PtCo/C nanoparticles. The XAS revealed that the time of CO treatments influence the surface population due to phase segregation. Catalysts treatment for 1, 3 and 5 h lead to higher population of Pt on the core and Co on the surface resulting in Pt rich in core—Co rich in shell. In contrast, CO treatments for 7, 10 and 15 h lead to higher population of Pt on the shell and Co on the core resulting in Pt rich in shell—Co rich in core. The electrochemical results showed that PtCo/C CO‐treatment is more active than commercial PtCo/C for the oxygen reduction reaction and it is found that PtCo/C CO‐treatment 3 h has the highest catalytic activity; because it has higher J Pt and J Co values, indicating a higher extent of Pt and Co alloying. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.