Formation of Pt-Ru Nanoparticles in Ethylene Glycol Solution: An in Situ X-ray Absorption Spectroscopy Study
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- 作者：Loka Subramanyam Sarma ; Ching-Hsiang Chen ; Sakkarapalayam Murugesan Senthil Kumar ; Guo-Rung Wang ; Shih-Chieh Yen ; Din-Goa Liu ; Hwo-Shuenn Sheu ; Kuan-Li Yu ; Mau-Tsu Tang ; Jyh-Fu Lee ; Christina Bock ; Ku
- 刊名：Langmuir
- 出版年：2007
- 出版时间：May 8, 2007
- 年：2007
- 卷：23
- 期：10
- 页码：5802 - 5809
- 全文大小：349K
- 年卷期：v.23,no.10(May 8, 2007)
- ISSN：1520-5827
文摘
The chemical state and formation mechanism of Pt-Ru nanoparticles (NPs) synthesized by using ethylene glycol(EG) as a reducing agent and their stability have been examined by in situ X-ray absorption spectroscopy (XAS) atthe Pt LIII and Ru K edges. It appears that the reduction of Pt(IV) and Ru(III) precursor salts by EG is not a straightforwardreaction but involves different intermediate steps. The pH control of the reaction mixture containing Pt(IV) and Ru(III)precursor salts in EG to 11 led to the reduction of Pt(IV) to Pt(II) corresponding to [PtCl4]2- whereas RuIIICl3 is changedto the [Ru(OH)6]3- species. Refluxing the mixture containing [PtCl4]2- and [Ru(OH)6]3- species at 160 
C for0.5 h produces Pt-Ru NPs as indicated by the presence of Pt and Ru in the first coordination shell of the respectivemetals. No change in XAS structural parameters is found when the reaction time is further increased, indicating thatthe Pt-Ru NPs formed are extremely stable and less prone to aggregation. XAS structural parameters suggest a Pt-richcore and a Ru-rich shell structure for the final Pt-Ru NPs. Due to the inherent advantages of the EG reduction method,the atomic distribution and alloying extent of Pt and Ru in the Pt-Ru NPs synthesized by the EG method are higherthan those of the Pt-Ru/C NPs synthesized by a modified Watanabe method.
C for0.5 h produces Pt-Ru NPs as indicated by the presence of Pt and Ru in the first coordination shell of the respectivemetals. No change in XAS structural parameters is found when the reaction time is further increased, indicating thatthe Pt-Ru NPs formed are extremely stable and less prone to aggregation. XAS structural parameters suggest a Pt-richcore and a Ru-rich shell structure for the final Pt-Ru NPs. Due to the inherent advantages of the EG reduction method,the atomic distribution and alloying extent of Pt and Ru in the Pt-Ru NPs synthesized by the EG method are higherthan those of the Pt-Ru/C NPs synthesized by a modified Watanabe method.