Synthesis, characterization, and testing of Pt-NPG catalysts developed by de-alloying of electrodeposited CuxAu(1-x) thin films

Electrodeposited CuxAu(1-x) thin films with different compositions have been found to undergo selective dissolution (de-alloying) in three specific potential ranges unlike their bulk counterparts that are known to de-alloy at composition dependent critical potentials. The general potential trend associated with co-existence of different thermodynamically stable alloy phases suggests increasing de-alloying rate in positive direction with the decreasing Cu content in the alloy. Following de-alloying, the resulting nanoporous Au (NPG) thin films exhibit significant surface area (SA) development, manifested by about three-fold increase in comparison with de-alloyed AgxAu(1-x) precursor counterparts. SEM characterization have seconded the SA results by revealing a finer structure of the NPG films which feature pores and ligaments of less than 10 nm. Formic acid oxidation tests suggest that the platinization of accordingly synthesized NPG thin films leads to the synthesis of catalysts exhibiting initial mass activities of 3-5 A mg(-1) (combined Pt-Au catalyst) and withstanding more than 2500 potential cycles. (C) 2016 Elsevier Ltd. All rights reserved.