Dealloying of Pt Bimetallic Catalysts at Constant Electrode Potentials

Abstract

We present the synthesis and controlled dealloying of homogeneously alloyed well-dispersed PtNi3 nanoparticles. This material was studied by dealloying at various constant potentials for 24 hours in order to investigate structural changes as function of electrode potentials. Using electrochemical analysis techniques we have provided evidence that the structure and composition of the dealloyed nanoparticles depended sensitively on the applied electrode potential, yet, surprisingly were also influenced by the presence or absence of adsorbed surface species such as hydrogen or oxygenates. Based on this finding, new dealloying strategies could be designed in order to enhance the catalytic activity and stability toward the oxygen reduction reaction (ORR).