This question may be broad, i have the doubt many people are preparing core- shell nano-particles with 2 metals or one metal and another metal oxide or polymer etc., some groups are working with simple bimetallic nano composite (not core shell), but their ultimate aim is to increase the stability and applicability of the material for suitable application. which one will give good output, because if we prepare core shell, the shell material may hinder the real activity of core but it may exhibit the property of the new shell material. in simple bimetallic materials it is the chance to expose the properties of both the materials.can you give to explanation to understand the concept behind these two types of materials.
Hi, first of all it is important to note that the property of the core material will vary with respect to the shell thickness. Protecting a metal core such as Ag or Au using an oxide or a polymer shell is for enhancing the chemical stability of the core and also for applying the as formed core-shell material for a specific application, say Photocatalysis.
For ex. consider Ag@TiO2 as a photocatalyst, . When UV light is irradiated on this system, there will be generation of electron-hole pairs on the TiO2 shell and the excess electrons will be transferred to Ag core since a Schottky barrier is established at the metal-semiconductor interface. Therefore this structure works effectively as a good photocatalyst.
http://pubs.acs.org/doi/abs/10.1021/ja042925a
http://www.sciencedirect.com/science/article/pii/S0304389410000294
On the contrary, Ag NPs are embedded on the surface of TiO2 to make it active under visible light irradiation. Herein, there is a resonant energy transfer from the plasmonic metal (Ag NPs) to TiO2.
http://dx.doi.org/10.1039/C3CS60043B
In case of a bimetallic system new property will be generated which will be a mixture of both the metals. For ex. in Fe-Ag and Ni-Ag bimetallic NPs, the plamonic character of Ag is found to be hindered with the addition of transition metals (Fe and Ni), which enables good nonlinear optical absorption.
Article Single step synthesis and optical limiting properties of Ni–...
thanks for your reply kishore, for my understanding i am asking this, u have explained about Ag, TiO2 core shell, is it possible to make TiO2 Np alone with the same property like Ag core TiO2 shell for the same application.
Yes of course. TiO2 is the most efficient semiconductor photocatalyst. You can find a lot of papers on the photocatalytic activity of TiO2. Once you read them, you will understand why people chose to make core-shell like Ag@TiO2 or Au@TiO2.
You may refer to this review paper http://pubs.acs.org/doi/full/10.1021/jp204364a
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science