Deposition gold nanoparticles

Jonas and coworkers deposited gold nanoparticles on silane-functionalized silica inverse opals prepared by the codeposition procedure. The gold/sihca hybrid inverse opals shown in Fig. 3a were then formed within the macrop-orous silica network by electroless deposition of HAuCU with hydroxylamine hydrochloride [35]. 

M. Sheffer and D. Mandler, Control of locally deposited gold nanoparticles on polyanihne films, Electrochim. Acta, 54, 2951-2956 (2009). 

By developing aerosol vapour assisted chemical vapour deposition (AACVD) techniques, Blackman and coworkers have deposited gold nanoparticles on the surface of WO3 nanoneedles in a single step. This method involves a codeposition using a precursor solution, which is deposited on a substrate in the form of an aerosol. Control over the nucleation and growth kinetics is realised by careful consideration of the deposition temperature and reactant concentration. Again, the choice of... 

Sepiolite has also been employed as support to deposit gold nanoparticles for designing catalyst for phenol acetylation reaction [95]. A gold hydrosol... 

Fig.17.7. SEM images of electrochemically deposited gold nanoparticles on an as-grown diamond film, (a) The sample was prepared in 0.5 M 0.5 M H2SO4 solution containing 5.0 x 10 M KAuCU, where the potential was held at 0 V for 14 sJ (h) after the deposition of Au the sample was oxidized at a potential of 1.300 V for 7 s, then swept linearly negatively firom 1.3 to 0.5 V with a scan rate of 0.030 V s in 0.1 M H2SO4 solution saturated with oxygen gas.

The last problem of this series concerns femtosecond laser ablation from gold nanoparticles [87]. In this process, solid material transforms into a volatile phase initiated by rapid deposition of energy. This ablation is nonthermal in nature. Material ejection is induced by the enhancement of the electric field close to the curved nanoparticle surface. This ablation is achievable for laser excitation powers far below the onset of general catastrophic material deterioration, such as plasma formation or laser-induced explosive boiling. Anisotropy in the ablation pattern was observed. It coincides with a reduction of the surface barrier from water vaporization and particle melting. This effect limits any high-power manipulation of nanostructured surfaces such as surface-enhanced Raman measurements or plasmonics with femtosecond pulses. 

One of the most interesting areas in the field of gold nanoparticles is when they are deposited over Ti02. As turns out from the following part, the results obtained by different research groups are still a subject of debate. 

Bates et al. reported the construction and characterization of a gold nanoparticle wire assembled using Mg -dependent RNA-RNA interactions for the future assembly of practical nanocircuits [31]. They used magnesium ion-mediated RNA-RNA loop-receptor interactions, in conjunction with 15 nm or 30 nm gold nanoclusters derivatized with DNA to prepare self-assembled nanowires. A wire was deposited between lithographically fabricated nanoelectrodes and exhibited non-linear activated conduction by electron hopping at 150-300 K (Figure 16). 

In order to deposit gold on the supports with high dispersion as nanoparticles (NPs) and clusters, there are at least nine techniques which can be classified into five categories well mixed precursors, specific surface interaction, mixing gold colloids [18], physical deposition [19,20], and direct reduction [21]. The former two categories are schematically presented in Figure 3. 

El-Deab M, Sotomura T, Ohsaka T. 2005a. Oxygen reduction at electrochemically deposited crystallographically oriented Au(100)-like gold nanoparticles. Electrochem Commun 7 29-34. 

Pol VG, Gedanken A, Calderon-Moreno J (2003) Deposition of gold nanoparticles on silica spheres a sonochemical approach. Chem Mater 15 1111-1118... 

Figure 2.9 DDT-stabilized silver nanoparticle films deposited via (a) hexane evaporation and (b) CXL nanoparticle deposition. Adapted from [15] 2005 American Chemical Society. DDT-stabilized gold nanoparticle...

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