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

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-enr...

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Bibliographic Details
Published in:Nanoscale 2023-01, Vol.15 (3), p.1136-1144
Main Authors: Jeon, Tae-Yeol, Lee, Han-Koo, Yoon, Geon-Hee, Lee, Si-Hwan, Yun, Hyung Joong, Kim, Ki-Jeong, Lee, Kug-Seung, Pinna, Nicola, Yu, Seung-Ho
Format: Article
Language:English
Subjects:
Alloying
Bimetals
Chemical reduction
Dealloying
Dissolution
Electrocatalysts
Hydroquinone
Nanoparticles
Oxygen enrichment
Oxygen reduction reactions
Platinum
Platinum base alloys
Selectivity
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Summary: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. Advantage of hydroquinone over sulfuric acid in selective dealloying of Pt-Ni nanoparticles to achieve a better ORR is shown. Hydroquinone treated nanoparticles exhibit the highest ORR activity after repeating the treatment twice.
ISSN:2040-3364
2040-3372
DOI:10.1039/d2nr02677e