Pt nanoplates were synthesized by galvanic displacement from Ag nanoplates and tested for performance as oxygen reduction catalysts for fuel cells. The Pt nanoplates exhibit improved specific activity by a factor of 3.7 compared to Pt nanoparticles (i(s)(0.9V) = 1000 and 270 mu A/cm(Pt)(2) for Pt nanoplates and nanoparticles, respectively) which indicates significant potential for future development of nanoplate electrocatalysts. The 2-d extended surface morphology of nanoplates was studied as a strategy to attain bulk material properties in a high surface area nanostructured material. The Pt nanoplates demonstrate more bulk-like properties approaching the specific activity of bulk polycrystalline Pt (i(s)(0.9V) = 2300 mu A/cm(Pt)(2)) and exceeding that for Pt black (i(s)(0.9V) = 840 mu A/cm(Pt)(2)). In addition, cyclic voltammetry reveals that the onset of oxide formation on the Pt nanoplates more closely resembles bulk polycrystalline Pt and Pt black as opposed to Pt nanoparticles. Pt nanoplate electrocatalysts synthesized by galvanic displacement highlight and expose a promising new strategy to achieve a class of nanostructured electrocatalysts with enhanced specific activity. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.029210jes] All rights reserved.