Atomically Resolved Dealloying of Structurally Ordered Pt Nanoalloy as an Oxygen Reduction Reaction Electrocatalyst

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• 作者：Andraž Pavlišič ; Primož Jovanovič ; Vid Simon Šelih ; Martin Šala ; Marjan Bele ; Goran Dražić ; Iztok Arčon ; Samo Hočevar ; Anton Kokalj ; Nejc Hodnik ; Miran Gaberšček
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：August 5, 2016
• 年：2016
• 卷：6
• 期：8
• 页码：5530-5534
• 全文大小：324K
• 年卷期：0
• ISSN：2155-5435

文摘

The positive effect of intermetallic ordering of platinum alloy nanoparticles on oxygen reduction reaction (ORR) activity has been well established. What is still missing is an understanding of selective leaching of the less noble metal from the ordered structure and its correlation to long-term ORR performance. Using a combination of kinetic Monte Carlo simulations and advanced characterization techniques, we provide unprecedented insight into dealloying of intermetallic PtCu₃ nanoparticles—a well-known binary alloy. Comparison of ordered and disordered samples with identical initial compositions and particle size distributions reveals an unexpected correlation: whereas the copper dealloying rates in the ordered and disordered counterparts are almost the same, in the ordered structure Pt atoms are surrounded by 15–30% more Cu atoms throughout all the stages of acid leaching. This more convenient Pt–Cu coordination explains the statistically significant increase of 23–37% in ORR activity of the ordered structure at all stages of alloy degradation.