Sierpinski gasket-like Pt-Ag octahedral alloy nanocrystals with enhanced electrocatalytic activity and stability
Sierpinski gasket-like Pt-Ag octahedral alloy nanocrystals with enhanced electrocatalytic activity and stability
复制标题
具有增强电催化活性和稳定性的谢尔宾斯基垫片状 Pt-Ag 八面体合金纳米晶
DOI：
10.1016/j.nanoen.2019.04.093
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发表时间：
2019
期刊：
影响因子：
17.6
通讯作者：
Xie Zhaoxiong
中科院分区：
文献类型：
--
作者：
Zhang Jiawei;Li Huiqi;Ye Jinyu;Cao Zhenming;Chen Jiayu;Kuang Qin;Zheng Jun;Xie Zhaoxiong
贵金属纳米晶体的结构工程可以使其结构多样化和复杂化，从而提供具有多功能性质的催化剂。本文报道了一种独特的Sierpinski衬垫状Pt-Ag八面体合金纳米结构，该结构具有三维超支化结构，包含丰富的富pt{111}稳定面和密集的低配位活性位点。与广泛接受的分形结构的远程极限扩散控制生长模型不同，我们的成功依赖于表面活性剂在晶体表面附近创造局部耗尽层。制备的Sierpinski衬垫状Pt-Ag八面体纳米晶体使我们实现了电催化剂的三个里程碑，即高催化活性、高耐久性和在酸性介质中对甲醇氧化反应的稳定性。具体来说，该催化剂表现出高比活性（6.61 mA cm−2，优于大多数已报道的pt基催化剂），出色的抗coads中毒能力和稳定性（经过2000次循环后，催化剂的形态和组成仍保持不变）。该研究为开发具有结构多样性和复杂性的分形纳米结构形式的高效催化剂提供了一种新的途径，以平衡催化剂活性和稳定性之间的微妙权衡。
Architectural engineering of noble metal nanocrystals can result in structural diversity and complexity, thereby providing catalysts with multifunctional properties. Herein, a unique Sierpinski gasket-like Pt–Ag octahedral alloy nanostructure with a three-dimensional hyperbranched architecture containing abundant well-defined Pt-rich {111} stable facets and dense low-coordinated active sites is reported. Unlike the well-accepted long-range limiting diffusion govened growth model for fractal structures, our success relies on creating local depletion layer near the crystal surface by surfactant. The as-prepared Sierpinski gasket-like Pt–Ag octahedral nanocrystals allows us to achieve three milestones for electrocatalysts, i.e. high catalytic activity, great durability, and stability towards the methanol oxidation reaction in acidic media. Specifically, the catalyst shows a high specific activity (6.61 mA cm−2, is superior than most of reported Pt-based catalysts), outstanding COads-poisoning tolerance and stability (the morphology and composition of the catalyst are preserved after 2000 cycles). This study points to a new approach to develop highly efficient catalysts in the form of fractal nanostructures with structural diversity and complexity to balance the delicate trade-off between activity and stability of catalysts.