_~TRQpUCTIONGeneral trends between geometricalelectronic properties and electrocatalyst activity have been the subject of many papers and review articles (1-4). In fact, much of the interest may be traced to the "volcano relationship" between the logarithm of the reaction rate and the free energy of adsorption,/kG~d ~, derived from electrochemical ~rInciples for the hydrogen evolution reaction (5,6). Assuming that/kS d remains constant, many workers hav~ ~bserved the "volcano type" behavior between the logarithm of the reaction rate and various quantities which may be rationalized to be proportional to/kH ~ . This assumption should . s * Electrochemacal Society Active Member.

Final reductions: Alloyed Pt–Cu nanodendrites are synthesized through a two‐step co‐reduction method, in which the reduction rate is controlled by the oxidative etchants and the reducing agents. These dendritic nanostructures are the result of overgrowth along the <111> axis of the face‐centered cubic structure and the coalescence of small dendritic seeds. These nanodendrites are highly active for methanol electro‐oxidation because of their unique structure and the bifunctionality of Pt and Cu.

We have studied the phenomenology of the catalytic peak for oxygen reduction on the Au(100) surface using cyclic potential voltammetry. In the potential region of this catalytic peak, oxygen is reduced via the overall four-electron process to hydroxide with a half-wave potential significantly positive to that of the Au(111), Au(110), and polycrystallite gold surfaces. We have studied the effect of sweep rate, sweep direction, and potential limits on the formation and definition of the catalytic peak. Our data indicate that an "oxidized Au(100)" surface is uniquely catalytic and selective for the overall fourelectron reduction of oxygen to hydroxide: However, the oxygen reduction activity of the ',reduced Au(100)" surface is analogous to that of the Au(111) surface. The reduced Au(100) surface promotes the two-electron reduction of oxygen to peroxide ion, and the half-wave potential for oxygen reduction is more negative. We conclude that a potential-induced kinetically limited process is operative during oxygen reduction on oxidized and reduced Au(100) surfaces. Processes consistent with our conclusion are: (i) potential-induced surface reconstruction between a catalytic and n0ncatalytic surface and (it) potential-induced formation and destruction of a catalytic oxide or hydroxide. Additionally, trace level ionic species other than hydroxide ion could account for the behavior of the oxidized and reduced Au(100) surfaces. PSI Technology Company assisted in meeting the publication costs of this article.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 131.215.225.9 Downloaded on 2015-07-06 to IP

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022ChemInform Abstract using the novel technique of cyclic potential ring measurements (CPRM) and for comparison the conventional RRDE technique. Using the CPRM method, in which the ring electrode is continuously cleaned by sweeping it anodically and cathodically to the peroxide detection potential, a considerably larger fraction of H2O2 (50-60%) is produced during oxygen reduction on oxidized Pt compared to 20-25% in the case of RRDE. It is concluded that this discrepancy is due to a changing ring surface at the RRDE and that peroxide plays a greater role in oxygen reduction on oxidized Pt in alkaline media than previously reported.