The Role of Citric Acid in Perfecting Platinum Monolayer on Palladium Nanoparticles during the Surface Limited Redox Replacement Reaction. Issue 12 (28th July 2016)

• Record Type: Journal Article
• Authors: Zhu, Shangqian; Yue, Jeffrey; Qin, Xueping; Wei, Zidong; Liang, Zhixiu; Adzic, Radoslav R.; Brankovic, Stanko R.; Du, Zheng; Shao, Minhua
• Is Part Of: Journal of the Electrochemical Society. Volume 163:Issue 12(2016)
• Page Start: D3040
• Page End: D3046
• Publication Date: 2016-07-28
• Subjects: Core-shell -- density functional theory -- fuel cells -- monolayer -- surfactant; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0061612jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Cu-mediated-Pt-displacement method that involves the displacement of an underpotentially deposited (UPD) Cu monolayer by Pt has been extensively studied to prepare core-shell catalysts. It has been found that Pt clusters instead of a uniform Pt monolayer were formed in the gram batch synthesis. With a suitable surfactant, such as citric acid, the Pt shell could be much more uniform. In this study, the role of citric acid in controlling the Cu-Pt displacement reaction kinetics was studied by electrochemical techniques and theoretical approaches. It was found that citric acid strongly adsorbed on Pd, Pt, Cu/Pd, and Pt/Pd surfaces, especially in the double layer region in acid solutions. The strong adsorption of citric acid slowed down the Cu-Pt displacement reaction. The main characteristics of such strong interaction most likely arises from the OH groups in the citric acid molecule according to the molecular dynamics simulation results.