局限在SiO <sub>2</sub>纳米球内部的Au-CuO异质结构纳米晶体之间转化化学的机理研究,Chemistry of Materials

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局限在SiO ₂纳米球内部的Au-CuO异质结构纳米晶体之间转化化学的机理研究
Chemistry of Materials ( IF 7.2 ) Pub Date : 2017-02-15 00:00:00 , DOI: 10.1021/acs.chemmater.6b05380
Ki-Wan Jeon , Dong-Gyu Lee , You Kyung Kim , Kangkyun Baek ₁ , Kimoon Kim ₁ , Taewon Jin , Ji Hoon Shim , Jeong Young Park , In Su Lee

Affiliation

通过采取NANOSPACE-局限于纳米晶体的转换协议的优点通过在SiO内的高温固相反应₂纳米球，进行了深入的研究进行到在Au-CuO的独特变行为异质结构纳米晶体（HNCS），这是在嵌入的AuCu合金纳米晶体（NC）的氧化退火过程中发现的。可以通过调节AuCu NCs中的退火温度（T _ann）或Cu含量（P _cu）来确定[电子邮件保护]和异二聚体之间的氧化AuCu NCs的异质结结构类型；[电子邮件保护]仅在低温下产生（T _ann≤250°C）或具有非常低的Cu含量（P _cu = 2.1），而在大多数情况下，在较高的热处理（> 250°C）下，Au / CuO异二聚体是主要产物。对HNC之间转换的系统研究可以通过动力学访问[电子邮件保护]来阐明Au / CuO异二聚体的独特进化途径，揭示了被包囊的Au核的逃逸运动，这通过较厚的CuO壳层更容易实现。这也证明了[受电子邮件保护]的高热稳定性。由于在CuO壳上没有足够的压缩晶格斑，无法驱动形态转变为异二聚体，因此壳厚度非常薄。此外，对于在CO催化氧化过程中具有最低Cu含量的[受电子邮件保护]，可以检测到更高的操作稳定性，这与其抗热变形性相关。

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Mechanistic Insight into the Conversion Chemistry between Au-CuO Heterostructured Nanocrystals Confined inside SiO2 Nanospheres

By taking advantage of a nanospace-confined nanocrystal conversion protocol via high-temperature solid-state reaction within the SiO₂ nanosphere, an in-depth study was conducted into the unique transformation behavior of the Au-CuO heterostructured nanocrystals (HNCs), which was discovered during the oxidative annealing of the embedded AuCu alloy nanocrystal (NC). The type of heterojuction structure of the oxidized AuCu NCs, between [email protected] and heterodimer, could be determined by modulating either the annealing temperature (T_ann) or Cu contents (P_cu) in AuCu NCs; [email protected] was generated only either at low temperature (T_ann ≤ 250 °C) or with very low Cu contents (P_cu = 2.1), whereas the Au/CuO heterodimer was obtained as a major product in most of the cases at relatively high heat treatment (>250 °C). The systematic investigation of the conversion between HNCs could elucidate the distinct evolution pathway of the Au/CuO heterodimer via the kinetically accessed [email protected], revealing the escaping motion of the encapsulated Au core, which is more facilitated through a thicker CuO shell. This also demonstrated the high thermal stability of the [email protected] with a very thin shell thickness due to the insufficient compressive lattice stain on the CuO shell to drive the morphological transformation into the heterodimer. Moreover, the higher operational stability could be detected for the [email protected] with the lowest Cu content during catalytic CO oxidation, which correlates with its resistance against the thermal deformation.

更新日期：2017-02-15

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