Catalytic Pt-on-Au nanostructures: why Pt becomes more active on smaller Au particles.
Catalytic Pt-on-Au nanostructures: why Pt becomes more active on smaller Au particles.
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DOI：
10.1021/nn204378t
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发表时间：
2012-03
期刊：
影响因子：
17.1
通讯作者：
Guirong Zhang;Dan Zhao;Yuanyuan Feng;Bingsen Zhang;D. Su;Gang Liu;Bo-Qing Xu
中科院分区：
文献类型：
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作者：
Guirong Zhang;Dan Zhao;Yuanyuan Feng;Bingsen Zhang;D. Su;Gang Liu;Bo-Qing Xu
铂是一种广泛用于催化纳米结构的贵金属。设计含Pt的双金属或多金属纳米结构的表面电子结构以提高Pt的固有活性和分散性仍然是一个挑战。通过使用尺寸范围为2-14 nm的一系列单分散Au纳米颗粒构建Pt-on-Au（Pt^Au）纳米结构，我们在此公开了一种新的方法，该方法通过减小Au纳米颗粒的尺寸来稳定地改变Pt在电催化中的两种性质。Pt分散和其表面电子结构的组合调谐示出作为Au的尺寸和价带结构的变化的结果，这导致小Au纳米颗粒上的Pt质量活性显著增强。在最小的Au纳米颗粒（2 nm）上完全分散的Pt实体表现出迄今为止对甲酸电氧化的最高质量活性，比常规Pt/C催化剂高2个数量级（75-300倍）。建立了Pt^Au纳米结构中Pt本征活性与Pt实体及其底层Au纳米颗粒的实验确定的表面电子结构（d带中心能量）之间的基本关系。
Platinum is a widely used precious metal in many catalytic nanostructures. Engineering the surface electronic structure of Pt-containing bi- or multimetallic nanostructure to enhance both the intrinsic activity and dispersion of Pt has remained a challenge. By constructing Pt-on-Au (Pt^Au) nanostructures using a series of monodisperse Au nanoparticles in the size range of 2-14 nm, we disclose herein a new approach to steadily change both properties of Pt in electrocatalysis with downsizing of the Au nanoparticles. A combined tuning of Pt dispersion and its surface electronic structure is shown as a consequence of the changes in the size and valence-band structure of Au, which leads to significantly enhanced Pt mass-activity on the small Au nanoparticles. Fully dispersed Pt entities on the smallest Au nanoparticles (2 nm) exhibit the highest mass-activity to date towards formic acid electrooxidation, being 2 orders of magnitude (75-300 folds) higher than conventional Pt/C catalyst. Fundamental relationships correlating the Pt intrinsic activity in Pt^Au nanostructures with the experimentally determined surface electronic structures (d-band center energies) of the Pt entities and their underlying Au nanoparticles are established.