Structure/Processing/Properties Relationships in Nanoporous Nanoparticles As Applied to Catalysis of the Cathodic Oxygen Reduction Reaction
Structure/Processing/Properties Relationships in Nanoporous Nanoparticles As Applied to Catalysis of the Cathodic Oxygen Reduction Reaction
复制标题
DOI：
10.1021/ja3019498
复制
发表时间：
2012-05-23
影响因子：
15
通讯作者：
Erlebacher, Jonah
中科院分区：
文献类型：
--
作者：
Snyder, Joshua;McCue, Ian;Erlebacher, Jonah
我们对阴极氧还原反应中脱合金纳米多孔Ni/Pt合金纳米颗粒的形成和活性进行了全面的实验研究。通过解决溶剂热合成过程中的成核动力学，我们开发了一种方法来控制Ni/Pt合金纳米颗粒的尺寸和组成在很宽的范围内，同时保持足够的尺寸分布。这些尺寸控制的纳米颗粒的电化学去合金化被用来探索纳米颗粒内的分级纳米孔隙率可以演变的条件。我们的研究结果表明，为了发展完全形成的孔隙度，颗粒必须具有类似于15 nm的最小直径，结果与表面动力学过程中发生的脱合金。纳米多孔纳米颗粒具有直径约为2 nm的韧带和空隙，通常与小得多的颗粒相关的高表面积/质量比，以及与覆盖Ni/Pt合金核的Pt骨架一致的组成。电化学测试结果表明，碳载纳米多孔Ni/Pt纳米颗粒的氧还原活性是商业Pt/C催化剂的近4倍，甚至超过了无孔Pt骨架Ni/Pt合金纳米颗粒。
We present a comprehensive experimental study of the formation and activity of dealloyed nanoporous Ni/Pt alloy nanoparticles for the cathodic oxygen reduction reaction. By addressing the kinetics of nucleation during solvothermal synthesis we developed a method to control the size and composition of Ni/Pt alloy nanoparticles over a broad range while maintaining an adequate size distribution. Electrochemical dealloying of these size-controlled nanoparticles was used to explore conditions in which hierarchical nanoporosity within nanoparticles can evolve. Our results show that in order to evolve fully formed porosity, particles must have a minimum diameter of similar to 15 nm, a result consistent with the surface kinetic processes occurring during dealloying. Nanoporous nanoparticles possess ligaments and voids with diameters of approximately 2 nm, high surface area/mass ratios usually associated with much smaller particles, and a composition consistent with a Pt-skeleton covering a Ni/Pt alloy core. Electrochemical measurements show that the mass activity for the oxygen reduction reaction using carbon-supported nanoporous Ni/Pt nanoparticles is nearly four times that of commercial Pt/C catalyst and even exceeds that of comparable nonporous Pt-skeleton Ni/Pt alloy nanoparticles.