Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, People's Republic of China.
Nanotechnology. 2012 Sep 14;23(36):365601. doi: 10.1088/0957-4484/23/36/365601. Epub 2012 Aug 21.
Galvanic replacement (GR) reactions involving active-metal nanoparticles (NPs) as seeds have a number of distinctive features and can produce various noble-metal nanoparticles. The oxide layer on the surfaces of such active-metal seeds may make a remarkable impact on the final products. Taking the Zn/Cu(2+) system as a model, we show that the GR reaction of pure Zn seeds with Cu(2+) ions leads to Cu nanodendrites, while oxide-covered Zn seeds result in ultrafine Cu NPs. We demonstrate here that the oxide layer does not block the GR reaction but slows down its rate. We also show that the growing Cu NPs can eventually detach from their ZnO substrate because of poor adhesion and disperse in the reaction liquid very well. Our studies provide detailed information on mechanisms of the GR reaction involving active-metal seeds, and therefore may be useful for further control of the morphology and properties of products prepared via this approach.
电置换（GR）反应涉及作为种子的活性金属纳米粒子（NPs），具有许多独特的特点，并可产生各种贵金属纳米粒子。这种活性金属种子表面的氧化层可能对最终产物产生显著的影响。以 Zn/Cu(2+)体系为例，我们表明纯 Zn 种子与 Cu(2+)离子的 GR 反应导致 Cu 纳米枝晶，而氧化层覆盖的 Zn 种子则导致超细微 Cu NPs。我们在这里证明氧化层不会阻止 GR 反应，而是会降低其反应速率。我们还表明，由于附着力差，生长中的 Cu NPs 最终可以从 ZnO 衬底上脱离，并在反应液中很好地分散。我们的研究提供了有关涉及活性金属种子的 GR 反应机制的详细信息，因此对于通过这种方法制备的产品的形态和性能的进一步控制可能是有用的。
