Au-Pd alloy and core-shell nanostructures: one-pot coreduction preparation, formation mechanism, and electrochemical properties.

It is a known fact that Pd-based bimetallic nanostructures possess unique properties and excellent catalytic performance. In this work, the Au-Pd alloy and core-shell nanostructures have been prepared by a simple one-pot hydrothermal coreduction route, and their formation process and mechanism are discussed in detail. A reducing capacity-induced controlled reducing mechanism is proposed for the formation process of Au-Pd bimetallic nanostructures. CTAB plays a key role in the formation of alloy Au-Pd nanostructures. When CTAB is absent, the products are typical core-shell nanostructures. Moreover, the as-prepared nanostructures exhibit excellent electrocatalytic ORR performance in alkaline media, especially for Au-Pd alloy nanostructures. The overpotential of oxygen reduction gets reduced significantly, and the peak potential is positive-shifted by 44 and 34 mV in comparison with the core-shell ones and Pd/C catalyst, respectively. Thus, the controllable preparation and excellent electrocatalytic properties will make them become a potentially cheaper Pd-based cathodic electrocatalyst for DAFCs in alkaline media.