A standing Ag nanosheet array was successfully deposited using an electrochemical method. The results demonstrated that the adsorption of polyvinylpyrrolidone (PVP) over the Ag (111) plane during deposition (1) inhibits the crystalline growth in the [111] direction, (2) stacks atomic faults in the fcc structure, and (3) forms a standing Ag nanosheet composed essentially of (111) planes. In an application, this Ag nanosheet array can be successfully used as an oxygen reduction catalyst. Based on Koutecky-Levich equation, the involved electron number at -0.2 V was 3.97. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.