掺杂剂
氧化物
材料科学
钙钛矿(结构)
化学物理
金属
钝化
退火(玻璃)
空间电荷
表面电荷
纳米技术
化学工程
兴奋剂
复合材料
化学
光电子学
物理化学
冶金
电子
工程类
物理
量子力学
图层(电子)
作者
Moritz L. Weber,Břetislav Šmíd,U. Breuer,Marc‐André Rose,Norbert H. Menzler,Regina Dittmann,Rainer Waser,Olivier Guillon,Felix Gunkel,Christian Lenser
标识
DOI:10.26434/chemrxiv-2022-v9z6n
摘要
Nanostructured composite electrode materials play a major role in the field of catalysis and electrochemistry. Self‐assembly of metallic nanoparticles on oxide supports via metal exsolution relies on the transport of reducible dopants towards the perovskite surface to provide accessible catalytic centers at the solid/gas interface. However, it is unclear if exsolution can be driven from the oxide bulk or if the process is limited to surfaces and interfaces, where strong electrostatic gradients and space charges typically control the properties of oxides. Here we reveal that the nature of the surface‐dopant interaction is the main determining factor for the exsolution kinetics of nickel in SrTi0.9Nb0.05Ni0.05O3‐ẟ and that the exsolution depth is strongly limited to the near‐surface region of the perovskite oxide. Electrostatic interaction of dopants with surface space charge regions forming upon thermal annealing result in strong surface passivation i.e. a retarded exsolution response. We furthermore demonstrate the controllability of the exsolution response via engineering of the perovskite surface chemistry. Our findings indicate that tailoring the electrostatic gradients at the perovskite surface is an essential step to improve exsolution type materials in catalytic converters.
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