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【答案】应助回帖
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超级老快: 金币+70, 翻译EPI+1, ★★★很有帮助 2016-12-10 15:01:07
1.由于Al2O3是玻璃网络中间体，在不同的情况下可以作为[AlO4]四面体进入玻璃网络结构形成体，也可以变为[AlO6]2-六面体游离于玻璃网络结构之外形成修饰体。玻璃热处理过程中，一部分游离于网络结构之外的[AlO6]2-六面体逐渐转变为[AlO4]四面体，并与游离于玻璃基质中的Ag+发生置换反应，失去电子与O2-离子，形成[AlO4]四面体和Ag0离子。Ag+被还原成Ag原子，在基质中Ag+与原子相互聚集团簇，不断形成Ag的二聚体、三聚体乃至多聚体等分子团簇形式，并最终在出现了Ag纳米颗粒的形成和析出，其机理图可见图所示。
As an intermediate of glass network, Al2O3 under different circumstance can be incorporated into glass either as [AlO4] tetrahedron glass former as a part of glass network, or [AlO6]2 hexadron glass modifier isolated from glass network structure. Under heat treatment, a portion of the isolated [AlO6]2 hexadrons react with Ag+ which is also isolated from the network, gradually turn to [AlO4] tetrahedron and AgO. Ag+ and Ag interact to form dimer, trimer and oligomer molecular clusters, eventually precipitate out as Ag nanoparticles. The mechanism is shown in Figure Z.
2.此外，我们对样品的激发光谱也进行了测试，如图分别在450nm和500nmAg团簇发光的波长监控下，激发光谱均存在280nm和340nm的两个宽带激发峰，分别可归属为Ag+和Ag团簇的电子跃迁吸收。
In addition, we measured emission spectrum for the sample, as shown in Figure X, when monitored for 450 nm and 500 nm emission characteristic to Ag clusters, two broad excitation peaks also co-existed at 280 and 340 nm, which can be assigned to Ag+ and Ag cluster electron transition, respectively. |
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