Understanding adsorbate-induced surface segregation in PtCo/C electrocatalyst

Abdul Hamid Budiman, Widodo Wahyu Purwanto, Eniya Listiani Dewi, Rinaldy, Bing Joe Hwang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)604-612
Number of pages9
JournalAsia-Pacific Journal of Chemical Engineering
Volume7
Issue number4
DOIs
Publication statusPublished - 1 Jul 2012

Keywords

  • alloying extent
  • coordination number
  • phase segregation
  • XAS
  • XRD

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