Sub 10 nm Pd core @Pt shell nanocrystals (NCs) were prepared by a facile and green reduction method in aqueous solutions using commercially available and nontoxic poly(ethylene oxide)−poly(propylene oxide)−poly-(ethylene oxide) amphiphilic triblock copolymers as the reductant, stabilizer, and capping agent. The growth mode and morphology of the Pt shell on the Pd surface can be adjusted simply by the Pt/Pd molar ratio. The activity of carbonsupported Pd@Pt NCs toward oxygen reduction reaction exhibited a Pt shell morphology dependence, with Pd 2 @Pt 1 (Pt/Pd molar ratio 1/2) having the highest mass activity and Pd 1 @Pt 2 (Pt/Pd molar ratio 2/1) having the best areaspecific activity, and both of them were significantly enhanced in comparison with that of commercial Pt/C catalysts. Moreover, single-fuel-cell testing indicated superior activity and durability of Pd 2 @Pt 1 NCs, which made Pd 2 @Pt 1 NCs promising cathode catalysts for fuel cell applications.

A super gelator (F3) with an excellent gelation ability was synthesized; the organogel of F3 could allow two channel recognition of F-, AcO- and H2PO4- through proton controlled reversible sol-gel transition and color changes.

No abstract