Noble metal clustering and nanopillar formation in an oxide matrix
Noble metal clustering and nanopillar formation in an oxide matrix
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DOI：
10.7567/1347-4065/ab57e2
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发表时间：
2019-12
影响因子：
1.5
通讯作者：
M. Lippmaa;Seiji Kawasaki;R. Takahashi;Takahisa Yamamoto
中科院分区：
文献类型：
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作者：
M. Lippmaa;Seiji Kawasaki;R. Takahashi;Takahisa Yamamoto
用于太阳能收集和分解水制氢的光电化学电极有两个基本功能区：一个是通过光吸收产生光载流子，另一个是通过电极表面的电化学水还原产生氢气。我们发现贵金属(Pt、Ir、Pd、Rh)的自发偏析可以用来生长由氧化物半导体基质(SrTiO_3)和垂直排列的金属纳米管阵列组成的复合材料，这两个功能区可以独立设计。我们讨论了贵金属的分凝机制，生长初期的聚集，以及几种不同贵金属纳米管束形成的热力学和动力学方面。特别是，我们重点研究了金属和氧化物物种的表面扩散以及贵金属的包裹在垂直排列的纳米复合材料形成中的作用。
Photoelectrochemical electrodes used for solar energy harvesting and hydrogen production by water splitting have two essential functional regions: one for photocarrier generation by light absorption and another for hydrogen generation by electrochemical water reduction at the electrode surface. We show that spontaneous segregation of noble metals (Pt, Ir, Pd, Rh) can be used to grow composite materials consisting of an oxide semiconductor matrix (SrTiO3) and an array of vertically-aligned metal nanopillars that allow these two functional regions to be independently engineered. We discuss the noble metal segregation mechanisms, clustering at the initial growth stage, and the thermodynamic and kinetic aspects of nanopillar formation for several different noble metals. In particular, we focus on the role of surface diffusion of metal and oxide species and noble metal encapsulation in the formation of vertically-aligned nanopillar composite materials.