Carbon supported silver nanowires with enhanced catalytic activity and stability used as a cathode in a direct borohydride fuel cell

Abstract

Carbon supported silver nanowires prepared via a wet chemical method have been used as a cathode catalyst in a direct borohydride fuel cell. Structural characterization reveals that most of the silver nanowires are bicrystals twinned at the {111} planes with a corresponding growth direction of . The silver nanowires and carbon particles form an open porous microstructure, in which the silver nanowires are sufficiently surrounded by carbon particles, while also retaining plenty of free surfaces. The carbon supported silver nanowire catalyst exhibits a better catalytic activity for the oxygen reduction reaction in an alkaline medium than carbon supported silver nanoparticles. The cell performance and durability are improved when using the carbon supported silver nanowires as a cathode catalyst compared with commercial Ag/C. The anisotropic growth of the silver nanowires and the open porous microstructure help to maintain the structural stability resulting in better electron transport properties and fewer defect sites, which are beneficial for achieving high electrocatalytic activity and good durability. Thus, carbon supported silver nanowire cathodes are promising candidates for cathode catalysts in direct borohydride fuel cells.