title: Intermediate stages of electrochemical oxidation of single-crystalline platinum revealed by in situ Raman spectroscopy.
abstract: Understanding the atomistic details of how platinum surfaces are oxidized under electrochemical conditions is of importance for many electrochemical devices such as fuel cells and electrolysers. Here we use in situ shell-isolated nanoparticle-enhanced Raman spectroscopy to identify the intermediate stages of the electrochemical oxidation of Pt(111) and Pt(100) single crystals in perchloric acid. Density functional theory calculations were carried out to assist in assigning the experimental Raman bands by simulating the vibrational frequencies of possible intermediates and products. The perchlorate anion is suggested to interact with hydroxyl phase formed on the surface. Peroxo-like and superoxo-like two-dimensional (2D) surface oxides and amorphous 3D α-PtO2 are sequentially formed during the anodic polarization. Our measurements elucidate the process of the electrochemical oxidation of platinum single crystals by providing evidence for the structure-sensitive formation of a 2D platinum-(su)peroxide phase. These results may contribute towards a fundamental understanding of the mechanism of degradation of platinum electrocatalysts.
authors: Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, PO Box 9502, 2300 RA Leiden, The Netherlands.
authors: Yi-Fan
authors: YF
authors: Huang
authors: ChemE, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.|Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.
authors: Patricia J
authors: PJ
authors: Kooyman
authors: Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, PO Box 9502, 2300 RA Leiden, The Netherlands.
authors: Marc T M
authors: MT
authors: Koper