Preparation and characterisation of platinum- and gold-coated copper, iron, cobalt and nickel deposits on glassy carbon substrates

• Published in: Electrochimica acta Vol. 53; no. 22; pp. 6559 - 6567
• Main Authors: Papadimitriou, S., Tegou, A., Pavlidou, E., Armyanov, S., Valova, E., Kokkinidis, G., Sotiropoulos, S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 20.09.2008; Elsevier
• Subjects: Bimetallic catalysts; Chemistry; Electrochemistry; Electrodes: preparations and properties; Electroless deposition; Exact sciences and technology; General and physical chemistry; Gold catalysts; Hydrogen evolution; Other electrodes; Platinum catalysts; Bimetallic catalysts; Hydrogen evolution; Gold catalysts; Platinum catalysts; Electroless deposition; Hydrogen; Gas release; Iron; Cobalt; Acidic solution; Surface structure; Electrodes; Electrocatalysis; Platinum; Surface properties; Copper; Electrochemical reaction; Modified material; Scanning electron microscopy; Gold; Core-shell particulate; Transition metal; Carbon; Tafel curve; Perchloric acid; Morphology; Nickel; Kinetics; Surface area; Catalyst activity; Electroless plating; Glassy state
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2008.04.015

Pt- and Au-coated Cu, Fe, Co and Ni deposits have been formed on glassy carbon (GC) substrates by electrodeposition of controlled amounts of the core metal onto the substrate and its subsequent partial replacement by Pt or Au upon immersion into a chloroplatinic or chlorolauric solution. This process resulted in a thin Pt or Au shell over the bimetallic particle as electrochemical evidence suggests, while indicative sputter-etch Auger Electron Spectroscopy points to the coexistence of the two metals in the particle core. SEM/EDS characterisation of the deposits revealed the existence of Pt(M) and Au(M) extensively agglomerated nanoparticles (M: Cu, Fe, Co, Ni). The surface electrochemistry of the deposits (hydrogen adsorption/desorption on Pt and oxide formation/stripping on Au) proved the complete coverage of the bimetallic particles by Pt or Au and allowed an estimate of their electroactive surface area. The study of hydrogen evolution at these deposits points to a modification of the electronic properties of the Pt and Au surface layers by the core metal (due to strain effects and/or ligand–electronic interactions) and further confirmed that these layers form a very thin outer shell.