Nanoparticles colloids and

Lithography techniques such as nanosphere lithography and electron-beam lithography are ideal methods to fabricate the reproducible SERS substrates [51]. They have been shown to improve the substrates performance by controlling the size and shape of colloidal nanoparticles and interparticle spacing [52]. Lithography techniques are simple to implement and of low cost. These advantages make them suitable platforms for the fabrication of SERS-active substrate. 

The preparation of nanocomposites by cogelation of preformed colloidal nanoparticles and of TEOS has also been adopted for the preparation of Ag-Si02 [56] and AuASi02 [57] nanocomposites. 

Deposition of Cold Nanoparticles and Clusters onto Carbons and Polymers 3.2.2.1 Cold Colloid Immobilization (Cl)... 

In order to obtain Pt nanoparticles, aqueous solution of 10 M K2PtCl4, which contained 10 M (as monomer unit) of poly-NIPA or poly-NEA, was bubbled with Ar gas and then H2 gas. Then the reaction vessel was sealed tightly and kept in a water bath at a suitable temperature. At given reaction times, the vessels were opened and the samples for transmission electron microscopy (TEM) were prepared by soaking a grid (carbon substrate, Oken) in the colloidal solution and then drying it in the air. The TEM (Hitachi H-8100) was operated at 200 kV. 

Multipods and Dendritic Nanoparticles of Platinum Colloidal Synthesis and Electrocatalytic Property... 

The catalytic activity of the Ru/Sn02 nanocomposite was eight times higher than that of the most effective Ru metal catalyst reported previously [56]. An o-CAN selectivity over 99.9% at a substrate conversion of 100% was obtained over the Ru/Sn02 catalyst. This selectivity was comparable to the result reported for a boride-modified PVP-Ru colloidal catalyst [56,57], and was better than that of the PVP-Ru catalyst with the same Ru nanoparticles. The Sn02 nanoparticles remarkably promoted both the catalytic activity and selectivity of the Ru nanoclusters. An extremely low dechlorination rate of o-CAN in the absence of o-CNB was observed over this catalyst, which was 20-fold lower than that over the PVP-Ru colloidal catalyst, and was 73-fold lower when compared with a Ru/Si02 nanocomposite catalyst. 

The main advantage of the salt reduction method in the liquid phase is that it is reproducible and allows colloidal nanoparticles with narrow size distribution to be prepared. 

Wu YD, Wang LS, Xiao MW, Huang XJ (2008) A novel sonochemical synthesis and nanostructured assembly of polyvinylpyrrolidone-capped CdS colloidal nanoparticles. J Non-Cryst Solid 354(26) 2993-3000... 

Wang, Z.F., Xiao, P.F., Shen, B. and He, N.Y. (2006) Synthesis of palladium-coated magnetic nanoparticle and its application in Heck reaction. Colloids and Surfaces A Physicochemical and Engineering Aspects, 276 (1-3), 116-121. 

---