Bifunctional Ag@SiO <sub>2</sub> /Au Nanoparticles for Probing Sequential Catalytic Reactions by Surface-Enhanced Raman Spectroscopy [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Basic Energy Sciences, 2017. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 245-251 : digital, PDF file
- Additional Creators:
- Brookhaven National Laboratory, United States. Department of Energy. Office of Basic Energy Sciences, and United States. Department of Energy. Office of Scientific and Technical Information
- Here, we report the synthesis of bifunctional Ag@SiO<sub>2</sub>/Au nanoparticles with an “islands in the sea” configuration by titrating HAuCl<sub>4</sub> solution into an aqueous suspension of Ag@SiO<sub>2</sub> core–shell nanocubes in the presence of NaOH, ascorbic acid, and poly(vinyl pyrrolidone) at pH 11.9. The NaOH plays an essential role in generating small pores in the SiO<sub>2</sub> shell in situ, followed by the epitaxial deposition of Au from the Ag surface through the pores, leading to the formation of Au islands (6–12 nm in size) immersed in a SiO<sub>2</sub> sea. Furthermore, by controlling the amount of HAuCl<sub>4</sub> titrated into the reaction system, the Au islands can be made to pass through and protrude from the SiO<sub>2</sub> shell, embracing catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol by NaBH4. And while the Ag in the core provides a strong surface-enhanced Raman scattering activity, the SiO<sub>2</sub> sea helps maintain the Au component as compact, isolated, and stabilized islands. The Ag@SiO<sub>2</sub>/Au nanoparticles can serve as a bifunctional probe to monitor the stepwise Au-catalyzed reduction of 4-nitrothiophenol to 4-aminothiophenol by NaBH<sub>4</sub> and Ag-catalyzed oxidation of 4-aminothiophenol to trans-4,4'-dimercaptoazobenzene by the O<sub>2</sub> from air in the same reaction system.
- Published through SciTech Connect., 02/22/2017., "bnl--113587-2017-ja", "KC0403020", ChemNanoMat 3 4 ISSN 2199-692X AM, and Wu, Yiren; Su, Dong; Qin, Dong.
- Funding Information:
- SC00112704 and 16060
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