Morphology and electrochemical properties of Pd-based catalysts deposited by different thin-film techniques

• Published in: International journal of hydrogen energy Vol. 39; no. 27; pp. 14701 - 14711
• Main Authors: Sarto, F., Castagna, E., De Francesco, M., Dikonimos, T.M., Giorgi, L., Lecci, S., Sansovini, M., Violante, V.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 12.09.2014; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Cyclic voltammetry; Electrocatalysts; Electrodeposition; Energy; Exact sciences and technology; Fuels; Hydrogen; Nanostructures; Palladium; Sputtering; Cyclic voltammetry; Electrodeposition; Palladium; Nanostructures; Electrocatalysts; Sputtering; Hydrogen; Nanostructure; Thin film; Electrocatalysis; Electrochemical properties; Morphology; Catalyst
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2014.07.038

Pd/C-based electrodes for fuel cells applications were prepared by galvanostatic electrodeposition and DC sputtering of palladium on gas diffusion layers. Different sets of samples were realized by varying the Pd load, for each technique. The surface morphology of the deposits was investigated by scanning electron microscopy. Cyclic voltammetry in acidic solution was applied to study the catalytic behavior of the freshly deposited samples and to follow their evolution with increasing cycle numbers. The results showed that, depending on the sputtering or electrochemical technique and metal load, samples grew with different morphologies and showed different electrochemical behaviors, with electroactive surface values ranging between a few tens to some hundreds m2/g. Sputtered films were characterized by a microstructure made of sub-micrometric cauliflower-shaped clusters and showed the highest electroactive surface values after prolonged voltammetric scanning. Pd hydride formation with both α and β phases and high hydrogen absorption capability were observed in some of the electrodeposited samples, in association to flower-like micrometric-size clustered structure and hydrogen codeposition during the electrochemical growth process. ▪ •Pd was deposited on carbon/PTFE GDL substrate by electrodeposition and sputtering.•Electrochemical properties were correlated to surface morphologies of deposits.•Sputtered samples showed cauliflower-like clusters and best EAS after CV cycling.•Pd hydride was formed in electrodeposits with flower-like clusters structure.