科研之友
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摘要
Controlling the morphologies of Pt nanocrystals provide effective opportunities to promote the electrochemical properties and enhance the mass activity. Recently we have reported that Pluronic F127 (PEO100PPO65PEO100) could serve as reducing reagent for synthesis of highly electrocatalytic activity of branched Pt nanocrystal. Herein, we further synthesize another novel Pt nanosponge foil (Pt-NSF) under the same system with Pluronic F127. We expect to build the relationship between block copolymer system and morphology design of synthesized nanocrystal with specific electrochemical property. The electrochemical active areas (ECSA) of Pt-NSF and Pt-black are of the order of 20 m(2) g(-1). On one hand, step atoms, dislocations, grain boundaries, which observed from HRTEM (high resolution transmission electron microscope), are all prevalent on Pt-NSF, which could serve as active adsorption sites. On the other hand, Pt-NSF looks like an aggregation of many Pt-black nanoparticles, the connection formed skeleton is conducive to electron transfer. These reasons aroused the mass activity and the specific activity of Pt-NSF were much higher than each of Pt-black toward the oxygen reduction reaction activity (ORR) at 0.9V respectively. Durability tests show that the ECSA of Pt-NSF and Pt-black declined, but the activity of Pt-NSF toward the ORR was almost unchanged. The impact of structures on the electrochemical properties is described in detail.
