Formation of AgPt alloy nanoislands via chemical etching with tunable optical and catalytic properties.
ABSTRACT An effective way is developed to fabricate AgPt alloy nanoislands on gold nanorods based on the galvanic replacement between Ag and PtCl(4)(2-) in the presence of cetyltrimethylammonium bromide (CTAB). The optical and catalytic properties benefit from the porous structure composed of AgPt nanoislands. A large red shift (265 nm) after etching is observed for longitudinal surface plasmon resonance (SPR) in comparison with Au@Pt0.1@Ag. Alloy compositions in bulk miscibility gap can be obtained and finely tuned from Ag(0.56)Pt(0.44) to Ag(0.38)Pt(0.62). A unique composition dependence is found for both electrocatalytic oxidation of methanol and catalytic oxidation of o-phenylenediamine (OPD) by hydrogen peroxide. In both systems, the highest catalytic activity is achieved at the alloy composition of Pt(0.62)Ag(0.38). Proper alloying with Ag not only improves the CO poisoning of Pt catalyst but also enhances the catalytic activity greatly.
Article: Preparation of Pt Ag alloy nanoisland/graphene hybrid composites and its high stability and catalytic activity in methanol electro-oxidation.[show abstract] [hide abstract]
ABSTRACT: ABSTRACT: In this article, PtAg alloy nanoislands/graphene hybrid composites were prepared based on the self-organization of Au@PtAg nanorods on graphene sheets. Graphite oxides (GO) were prepared and separated to individual sheets using Hummer's method. Graphene nano-sheets were prepared by chemical reduction with hydrazine. The prepared PtAg alloy nanomaterial and the hybrid composites with graphene were characterized by SEM, TEM, and zeta potential measurements. It is confirmed that the prepared Au@PtAg alloy nanorods/graphene hybrid composites own good catalytic function for methanol electro-oxidation by cyclic voltammograms measurements, and exhibited higher catalytic activity and more stability than pure Au@Pt nanorods and Au@AgPt alloy nanorods. In conclusion, the prepared PtAg alloy nanoislands/graphene hybrid composites own high stability and catalytic activity in methanol electro-oxidation, so that it is one kind of high-performance catalyst, and has great potential in applications such as methanol fuel cells in near future.Nanoscale Research Letters 01/2011; 6(1):551. · 2.73 Impact Factor