PNNL

Abstract

Controlling the nanostructure of a metallic catalyst material has become an efficient strategy to tune and to optimize its catalytic properties for electrochemical reactions. Reported herein is a unique nanoporous silver (np-Ag) structure, a multigrain, whose surface is predominantly enclosed by interlaced facets and thus defect-enriched surfaces. The synthesis is accomplished by a facile method involving hydrothermal treatment of a mixture containing Ag+ ions and reduced polyoxometalate (rPOM) nanoclusters. The confinement and reduction of Ag+ by rPOM creates the nanoporous structure of Ag. Catalytic results show that the np-Ag catalyst can electrocatalyze the oxygen reduction reaction (ORR) with activity superior to Pt/C in alkaline solution. The catalysts’ excellent electrocatalytic performance originates from the increased availability of surface defect and the features of nanoporous structure. It is anticipated that this work will offer a new route to surface-controlled synthesis and ORR catalysts design.