Fabrication of a Porous Pd Film on Nanoporous Stainless Steel Using Galvanic Replacement as a Novel Electrocatalyst/Electrode Design for Glycerol Oxidation, Electrochimica Acta, 2014, 136, 89-96, B. Rezaei, E. Havakeshian, Ali A. Ensafi
tIn this work, nanoporous stainless steel (NPSS) prepared by anodization process was used as an elec-trode material to support noble metal-based catalysts. To decorate NPSS with Pd, copper was depositedinto the pores of NPSS using pulsed electrodeposition, and followed by the galvanic replacement reactionbetween deposited Cu and PdCl2solution. The surface morphology and composition of the prepared elec-trode were determined using scanning electron microscopy (SEM), atomic force microscopy (AFM) andenergy dispersive X-ray spectroscopy (EDS). SEM and AFM images showed that self-organized nanoporeswith an average size of about 77 nm were formed on the stainless steel surface and then were successfullyfilled with Cu. Galvanic replacement resulted in the formation of a porous film with a high electrochemi-cally active surface area (EASA = 173.4 cm2mg−1) and greatly reducing Pd loading (29 g cm−2). The EDSanalysis revealed the presence of Cu and Pd in the prepared electrode (NPSS/Cu/Pd). Cyclic voltammetry,electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques were used to inves-tigate the electrochemical behavior of the NPSS/Cu/Pd electrode in alkaline media. It was found that theporosity of NPSS and the presence of Cu improve the long-term stability of the Pd film on the surface. Theelectrode exhibited a remarkable catalytic activity for electrooxidation of glycerol due to the large EASA.The obtained mass activity and onset potential for glycerol oxidation were 0.82 mA g−1Pdand −0.35 V,respectively, which are acceptable as compared with those of palladium-carbon substrates. The resultsalso indicated that the presence of Cu has a significant effect on the catalytic activity, the reaction kinet-ics and poisoning tolerance of the NPSS/Cu/Pd electrode. Accordingly, NPSS/Cu/Pd can be extended as apromising electrode for alcohol electrooxidation reactions in fuel cells and sensors.