高指数晶面和梯度组成的PtCu3@Pt3Cu@Pt纳米枝晶氧还原电催化剂性能

燃料电池作为一种清洁、高效的能量转换装置,其大规模应用受到阴极氧还原反应(ORR)动力学缓慢以及铂资源稀缺和价格高昂等的极大制约.尽管研究人员在过去几十年中付出了巨大努力,但研制高效、耐用的低Pt合金催化剂仍亟待突破.近年的研究表明,Pt的一些高指数晶面能够表现出比Pt(111)晶面更高的ORR活性,尤其是Pt(332...

High index surface-exposed and composition-graded PtCu3@Pt3Cu@Pt nanodendrites for high-performance oxygen reduction

Alloying and nanostructuring are two strategies used to facilitate the efficient electrocatalysis of the oxygen reduction reaction (ORR) by Pt, where the high index surfaces (HISs) of Pt exhibit superior activity for ORR. Here, we report the fabrication of PtCu3 nanodendrites possessing rich spiny branches exposing n(111) × (110) HISs. The dendrites were formed through an etching-modulated seeding and growing strategy. Specifically, an oxidative atmosphere was initially applied to form the concaved nanocubes of the Pt-Cu seeds, which was then switched to an inert atmosphere to pro-mote an explosive growth of dendrites. Separately, the oxidative or inert atmosphere failed to pro-duce this hyperbranched structure. Electrochemical dealloying of the PtCu3 nanodendrites pro-duced Pt3Cu shells with Pt-rich surfaces where HIS-exposed dendrite structures were maintained. The resulting PtCu3@Pt3Cu@Pt nanodendrites in 0.1 M HClO4 exhibited excellent mass and area specific activities for ORR, which were 14 and 24 times higher than that of commercial Pt/C, respec-tively. DFT calculations revealed that Cu alloying and HISs both contributed to the significantly enhanced activity of Pt, and that the oxygen binding energy on the step sites of HISs on the PtCu3@Pt3Cu@Pt nanodendrites approached the optimal value to achieve a near peak-top ORR activity.