Inner value: A new high‐concentration synthesis of Pt nanodendrite employs Au‐seed‐mediated growth inside a hollow silica nanosphere (see picture). The resulting material is substantially more active than commercial Pt black in the oxygen reduction reaction. Pt nanodendrite colloid with tunable dispersity as well as hybrid nanocrystals of various metals were also fabricated by the procedure.

Electrooxidation of glucose is investigated at nanoporous gold (NPG) with controlled surface structures by applying different deposition charges during the formation of AgÀAu layers. As the deposition charge increases, the NPG surfaces exhibit smaller ligament/pore structures and the electrocatalytic oxidation of glucose becomes more effective. Voltammetric responses of NPG suggest that the electrocatalytic oxidation arises from the enrichment of (110) or (100) surface orientation of gold with higher deposition charges. The electrooxidation of glucose is retained at NPG surfaces with higher deposition charges in the presence of Cl À , which suggests possible applications to the amperometric glucose detection in biological samples.

Nanostructured Au surfaces have unique and attractive properties as functional materials in many fields such as heterogeneous catalysis and electrocatalysis. Electrochemical deposition of Au has received much attention as a simple route for the fabrication of Au surface nanostructures. In this study, we report a simple electrodeposition of Au nanoplate structures from Au(CN)(2)(-) on Au surfaces in the absence of additives or premodification of electrode surfaces. The shape of the Au nanoplates as well as their surface structures is unique compared to other Au nanostructures electrodeposited from commonly employed AuCl(4)(-) complexes. The nanoplate Au surfaces exhibit unique electrocatalytic activities for oxygen reduction and glucose oxidation, which originate from the Au(110) and Au(100) facets present on nanoplate surfaces. A simple preparation of well-defined Au nanoplate structures would allow new opportunities in various areas utilizing Au-based substrates through further modification of Au surfaces.

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