Recently, the electrocatalytic activity of nanomaterials for the oxygen reduction reaction (ORR) is of great interest, particularly in the field of electrochemical energy-conversion systems such as fuel cells. Although Pt-based electrocatalysts are the most commonly used cathode catalysts in fuel cells due to the high activity toward a sluggish ORR, the high cost and limited supply of Pt as well as the requirement of a high Pt loading have impeded the wide spread applications of ORR. In this respect, a great deal of research has focused on the development of electrode materials as a replacement for Pt. Being a more economic and plentiful metal than Pt, Pd and Au have been investigated for their electrocatalytic activity. This presentation reports the facial synthesis and characterization of sponge-like nanoporous Pd (snPd) and Pd/Au (snPd/Au) prepared via a tailored galvanic replacement reaction (GRR). At first, a large amount of Co particles as sacrificial templates were electrodeposited onto the glassy carbon surface by using the cyclic voltammetric method. This is a key step to the subsequent fabrication of snPd/Au (or snPd) architectures by surface replacement reaction. By using Co films as sacrificial templates, snPd/Au catalyst has been prepared by a two-step GRR technique. In the first step, the Pd metal precursor, K2PdCl4, reacted spontaneously with the formed Co frames through the GRR, resulting in snPd. Then snPd/Au was prepared via the second GRR between snPd and various concentrations of Au precursor. The prepared snPd/Au catalyst was investigated as a cathodic electrocatalyst for ORR in alkaline solution. The morphology and surface area of the snPd/Au catalyst was characterized by FE-SEM, XRD, TEM, EDS and CV. Rotating disk electrode (RDE) voltammetric studies show that the snPd/Au has a higher catalytic activity than the commercial Pt/C catalyst.

Fabrication of sponge-like nanoporous Pd/Au electrocatalysts for oxygen reduction through a galvanic replacement reaction

246th National Meeting (2013)

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