Methanol electro-oxidation catalyzed by platinum deposited on various substrates using Electrochemical Atomic Layer Deposition (ECALD)

Abstract

Electrochemical atomic layer deposition technique was chosen in this study for the deposition of platinum nanostructures onto various substrates such as carbon paper, nickel foam and titanium mesh. Electrochemical evaluation and morphological studies were carried out on the electrodeposited Pt. Cyclic voltammograms of the electrodeposited platinum nanostructures showed features characteristic of polycrystalline platinum electrodes. The substrates were also modified with a layer of carbon black in 40 % Nafion. The Pt/C/Ni foam electrode with its higher real surface area proved to be the better substrate compared to others electrodes in terms of performance in hydrogen oxidation, methanol oxidation activity, CO tolerance in acidic electrolytes. Scanning electron microscopy images showed good quality deposits that uniformly covered the substrates and energy dispersive x-ray spectroscopy confirmed the presence of Pt in all electrodes. According to the Atomic Force Microscopy histogram analysis, the particle size was found to range from 24-99.2 nm. Inductively coupled plasma optical emission spectroscopy indicated an increase in weight with every repetition of Pt loading. The Pt/Ni foam electrode had a higher Pt loading due the higher surface area of Ni foam as compared to that of carbon paper and Ti mesh. This work has demonstrated the ease and flexibility of this technique for preparing nanostructures on various substrates.