Epitaxial Growth of Twinned Au鈥揚t Core鈥揝hell Star-Shaped Decahedra as Highly Durable Electrocatalysts

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• 作者：Ting Bian ; Hui Zhang ; Yingying Jiang ; Chuanhong Jin ; Jianbo Wu ; Hong Yang ; Deren Yang
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：15
• 期：12
• 页码：7808-7815
• 全文大小：562K
• ISSN：1530-6992

文摘

Pt epitaxial layer on a nanoparticle with twinned structure and well-defined shape is highly desirable in order to achieve high performance in both catalytic activity and durability toward oxygen reduction reaction (ORR). However, it remains tremendously challenging to produce conformal, heterogeneous, twinned nanostructures due to the high internal strain and surface energy of Pt. In addition, these twinned nanostructures may be subject to degradation in highly corrosive ORR environments due to the high energy of twin boundary. Here we report the synthesis of Au鈥揚t core鈥搒hell star-shaped decahedra bounded mainly by {111} facets, in which Pt shells with controlled thickness epitaxially grew on Au cores with a 5-fold twinned structure. The incorporation of the amine group decreases the surface energy of Pt by strong adsorption and thus facilitates the epitaxial growth of Pt on Au core instead of the dendritic growth. In addition, Br^{鈥?/sup> ion could largely stabilize the {111} facets of Pt, which prevent the formation of spherical nanoparticles. The Au鈥揚t core鈥搒hell decahedra with thicker Pt shell exhibited enhanced ORR properties in terms of activity and durability. Specifically, AuPt_1.03 star-shaped decahedra achieved the highest mass activity (0.94 mA/渭g_Pt) and area activity (1.09 mA/cm2_Pt), which is 鈭?.7 and 5 times, respectively, as high as those of the commercial Pt/C (ETEK). Significantly, such star-shaped decahedra were highly stable with 鈭?0% loss in area activity and 鈭?0% loss in mass activity after 30鈥?00 CV cycles in O₂ saturated acid solution.}