Controllable incorporation of Ag and Ag–Au nanoparticles in carbon spheres for tunable optical and catalytic properties
Controllable incorporation of Ag and Ag–Au nanoparticles in carbon spheres for tunable optical and catalytic properties
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DOI：
10.1039/c0jm00456a
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发表时间：
2010-06
影响因子：
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通讯作者：
S. Tang;S. Vongehr;Xiangkang Meng
中科院分区：
文献类型：
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作者：
S. Tang;S. Vongehr;Xiangkang Meng
以聚N-乙烯吡咯烷酮为还原剂，将多孔碳球（CS）悬浮于[Ag（NH3）2]+溶液中，通过微波加热，高收率地合成了含Ag纳米颗粒（NPs）的球形Ag-C复合材料。使用Ag-C复合物作为前体使我们能够将Au掺杂到CS的内部。通过将Ag-C复合材料浸入氯金酸（HAuCl 4）溶液中而不添加还原剂来制备各种Ag-Au掺杂的以及主要为Au的复合球。发现Au的产率比置换反应可以提供的要高得多，这是通过详细讨论决定纳米颗粒在CS中/上的位置的所涉及的生长机制来解释的。复合结构的光学性质和催化活性可通过由HAuCl 4浓度控制的Au与Ag原子比来调节。通过硼氢化钠还原4-硝基苯酚的实验表明，该复合物具有良好的催化活性。与单金属掺杂的CSs相比，复合材料的催化活性得到了很大的提高.
Spherical Ag–C composites containing Ag nanoparticles (NPs) have been synthesized in high yield by microwaving suspensions of porous carbon spheres (CSs) in [Ag(NH3)2]+ solutions with poly (N-vinylpyrrolidone) as the reducing agent. The use of Ag–C composites as precursors enables us to dope Au also into the CSs' interior. Various Ag–Au doped and also predominantly Au composite spheres are prepared via the immersion of the Ag–C composites in chloroauric acid (HAuCl4) solutions without additional reducing agent. The yield of Au is found to be much higher than a replacement reaction could provide, which is explained via a detailed discussion of the involved growth mechanisms that decide the locations of the NPs in/on the CSs. Optical properties and catalytic activities of the composite structures are tunable via the Au versus Ag atomic ratio as controlled by the HAuCl4 concentration. The composites exhibit excellent catalytic activity as demonstrated via the reduction of 4-nitrophenol by sodium borohydride. The catalytic activity of bimetallic composites is highly enhanced over the monometallically doped CSs.