Electrodeposition of gold

Hundreds of baths exist for electrodeposition of gold and its alloys . The latter are more wear resistant, so better for contacts . Polymers incorporated in cyanide-bath deposits affect wear and contact resistance . 

Jamil, E., et ah, Electrodeposition of gold thin films with controlled morphologies and their applications in electrocatalysis andSERS. Nanotechnology, 2012. 23(25) p. 255705. 

The electrodeposition of gold was made in an acidic electrolyte of 0.005 M HAUCI4 per liter. The open circuit potential (OCP) after deposition was +820 mV versus SCE. The pulse potentials were varied between +800 and +600 mV versus SCE. Particles between 10 and 500 nm diameter were prepared. 

T vo different approaches have been made to increase the maximum deposition rate which is reached under a given set of deposition conditions. The first approach involves addition of a depolarizer, such as lead or thallium ions [162-164]. These ions are known to adsorb strongly on gold and to bring about underpotential deposition (UPD) during electrodeposition of gold [165]. The depolarization effect amounts to as much as 0.2 V, as reported by Matsuoka et al. [164] and illustrated in Fig. 34. These authors show that addition of such depolarizers to a borohydride bath increases the deposition rate by a factor of as much as 8 to 10 (Fig. 35). 

Fig. 9 Cycling voltammetry (5 mV/sec) for gold electrodes of different roughness [28]. SI untreated (as received) surface. S2-S4 surfaces obtained by electrodeposition of gold at currents densities close to the limiting current density. Inset approximate values of the half-width of resonance. Curves S2 and S3 lie between curves SI and S4, in some parts coinciding with them. Arrows P(S1) and P(S4), show the peak currents for reduction of the surface oxide, measured for the surfaces SI and S4, respectively. (From [28])...

After plating, the first test of deposit was controlling the mechanical adhesion of Cu layers using the adhesive tape test. All films passed successfully this test whereas films obtained from an acid CUSO4 solution never passed the same test. The excellent mechanical properties of Cu films deposited from alkaline cyanide solutions is therefore presumably related to some specific interactions between the CN ions and the Si surface as recently observed for the electrodeposition of gold on n-Si from KAu(CN)2 solutions (6). 

J. Li and X. Lin, Electrodeposition of gold nanoclusters on overoxidized polypyrrole film modified glassy carbon electrode and its application for the simultaneous determination of epinephrine and uric acid under coexistence of ascorbic acid. Anal. Chim. Acta, 596, 222-230 (2007). 

Although this chapter is limited to electrodeposition of semiconductors, it is only fair to mention, even if briefly, some examples of electrodeposition of metal nanostructures. This is important because the principles and techniques used in electrodepositing metals are essentially the same as those used for depositing semiconductors - the main difference is that almost all studies on electrodeposition of nanocrystalline semiconductors involve compound semiconductors, with the added comphcations this entails. Examples include pulsed electrodeposition of metal multilayers [1, 2], porous membrane-templated electrodeposition of gold nanotubes [3], and Ni nanowires [4]. 

Oyama, T, Okajima, T, and Ohsaka, T. [2007]. Electrodeposition of gold at glassy carbon electrodes in room-temperature ionic liquids. / Electrochem. Soc, 154, pp. D322-D327. 

Afkhami et al. [162] used a graphite paste electrode containing MWCNT modified by the electrodeposition of gold NPs from a HAuCl solution to successfully determine cefixime, methadone [163], and nitrite [164] in a pharmaceutical form, in urine and saliva in several food stuffs and water samples, respectively. Fe203... 

Gao F, El-Deab MS, Ohsaka T (2005) Electrodeposition of gold nanorods with a unidirectional crystal growth and lower Au(l 11) facets area. Indian J Chem A 44(5) 932—937... 

Tian Y, liu H, Zhao G, Tatsuma T (2006) Shape-controlled electrodeposition of gold nanostructures. J Phys Chem B 110(46) 23478-23481... 

Xiao F, Mo Z, Zhao F, Zeng B (2008) Ultrasonic-electrodeposition of gold-platinum alloy nanoparticles on multi-walled carbon nanotubes-ionic liquid composite film and their electrocatalysis towards the oxidation of nitrite. Electrochem Commnn 10 1740-1743... 

Xiao F, Zhao F, Zhang Y, Guo G, Ztaig B (2009) Ultrasmiic electrodeposition of gold-platinum alloy nanoparticles on ionic liqnid-chitosan cmnposite film and their applicatimi in fabricating nonenzyme hydrogen peroxide sensors. J Phys Chcm C 113 849-855... 

Bozzini, B., D Urzo, L., Mele, C. and Romanello, V. (2008) A SERS investigation of cyanide adsorption and reactivity during the electrodeposition of gold, silver, and copper from aqueous cyanocomplexes solutions. The Journal of Physical Chemistry C, 112, 6352-6358. 

Dong S, Li N, Zhang P, Li Y, Chen Z, Huang T (2012) Fabrication of hemoglobin/ionic liquid modified carbon paste electrode based on the electrodeposition of gold nanoparticles/CdS quantum dots and its electrochemical application. Electroanal 24 (7) 1554-1560... 

Another strategy is chemical reduction of metal ions on a BCP-derived porous template in a metal salt solution, whereby reduced metals precipitate into the nanopores. The reduction can be achieved by electrodeposition, i.e., by applying an electric potential to a conductive substrate with a nanoporous film in a metal salt solution. As a metamaterial, nanostructured gyroidal gold was fabricated by a combination of BCP SA, ozonolysis, and electrodeposition of gold [38]. To that end, triblock terpolymer PI-h-PS-h-PEO solution was spun-cast (uito a transparent... 

Cross, C. E., Hemminger, J. C., and Penner, R. M. 2007. Physical vapor deposition of one-dimensional nanoparticle arrays on graphite Seeding the electrodeposition of gold nanowires. Langmuir 23 10372-10379. 

Halpem, A. R. Com, R. M. Lithographically patterned electrodeposition of gold, silver, and nickel nanoring arrays with widely tunable near-infrared plasmonic resonances. ACS Nano 2013,7,1755-1762. 

Hariri, M. B. Dolati, A. Moakhar, R. S. The potentiostatic electrodeposition of gold nanowire/nanotube in HAUCI4 solutions based on the model of recessed cyhndrical ultramicroelectrode array. J. Electrochem. Soc. 2013,160, D279-D288. 

Yang, G. Li, L. Jiang, J. Yang, Y. Direct electrodeposition of gold nanotube arrays of rough and porous wall by cyclic voltammetry and its applications of simultaneous determination of ascorbic acid and uric acid. Mater. Sci. Eng. C 2012, 32, 1323-1330. 

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