Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/16301
Title: Shape controlling of silver and gold nanocrystals
Authors: ZHOU XUEDONG
Keywords: Nanocrystal, Nanoprism, shape controlling, crystal growth, surface sensitive reaction, Ab initio modelling
Issue Date: 3-Aug-2009
Source: ZHOU XUEDONG (2009-08-03). Shape controlling of silver and gold nanocrystals. ScholarBank@NUS Repository.
Abstract: Reactive oxygen species (ROS) can be produced by hydrogen peroxide and the reduction of oxygen. In the hydrogen peroxide case, ROS can be produced by dissociation of hydrogen peroxide catalysed on silver nanocrystals or by light. In the oxygen case, ROS is produced by chemical or electrochemical reduction of oxygen. These ROS play a critical role in shaping silver and gold nanoprisms due to their surface sensitivity to silver and gold surfaces. Further, the crystal growth process is pH sensitive due to participation of ROS. The dimensions of silver and gold nanoprisms can be tuned by just adjusting the pH value of the growth bath.It is further found that citrate, ethanol and PVP activated by ROS can reduce silver ions and produce silver nanoprisms in high yield.Ab initio modelling discovers that dynamic symmetry breaking exists in the atomic processes of crystal growth due to the large difference in activation energy of gold atoms diffusing over the edge of Au (111)/Au (1-10) and Au (111)/Au (110). This atomic mechanism is key in determining the plate formation and is first reported in this study.
URI: http://scholarbank.nus.edu.sg/handle/10635/16301
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