Selective dealloying of chemically disordered Pt-Ni bimetallic nanoparticles for the oxygen reduction reaction

Tae Yeol Jeon, Han Koo Lee, Geon Hee Yoon, Si Hwan Lee, Hyung Joong Yun, Ki Jeong Kim, Kug Seung Lee, Nicola Pinna, Seung Ho Yu

Research output: Contribution to journalArticlepeer-review

Abstract

Changes in electronic and compositional structures of Pt-Ni electrocatalysts with 44% of Ni fraction with repeated chemical dealloying have been studied. By comparing the Pt-enriched surfaces formed using hydroquinone and sulfuric acid as a leaching agent, we found that hydroquinone generated Pt-enriched surfaces exhibit the highest oxygen reduction reaction (ORR) activity after repeating the treatment twice. In particular, it was found that while sulfuric acid causes an uncontrollable dissolution of Ni clusters, the unique selectivity of hydroquinone allows the preferential dissolution of Ni atoms alloyed with Pt. Despite its wide usage in the field, the results show that traditional acid leaching is unsuitable for Pt-Ni alloys with a high Ni content and an incomplete alloying level. We finally proved that the unique and lasting selectivity of hydroquinone enables an incompletely alloyed Pt-Ni catalyst to obtain a highly ORR active Pt shell region without an extensive loss of Ni.

Original languageEnglish
JournalNanoscale
DOIs
Publication statusAccepted/In press - 2022

ASJC Scopus subject areas

  • Materials Science(all)

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