Pulse electrodeposition

Morris GC, Vanderveen RJ (1993) Cadmium teUuiide films prepared by pulsed electrodeposition. Sol Energy Mater Sol Cells 30 339-351... 

Coutanceau C, Rakotondrainibe AF, Lima A, Gamier E, Pronier S, Leger JM, Lamy C. 2004. Preparation of Pt-Ru bimetallic anodes by galvanostatic pulse electrodeposition characterization and appbcation to the direct methanol fuel cell. J Appl Electrochem 34 61-66. 

Reisee et al. [52] first described a pulsed electrodeposition and pulsed out-of-phase ultrasound to prepare copper nanopowders. Such an electrochemical method has since then employed to synthesize a variety of nanoparticles. Mancier et al. [53] have prepared Cu20 nanopowders (8 nm) with very high specific surface area of 2,000 m2/g by pulsed ultrasound assisted-electrochemistry. 

FIGURE 9.10 TEM image of a Pt0 65Ru035/C catalyst prepared by galvanostatic pulse electrodeposition with t0ff= 2.5 s. 

Conditions of Catalyst Preparation by Galvanostatic Pulse Electrodeposition and... 

This critical compaction step is avoided in the case of the electrochemical route of pulsed electrodeposition (PED) [29] which transforms cations, i.e. atomic species, directly into nanomaterials without the detour via nanopartides. In this way densities up to 99% of the theoretical value can be achieved, such that these materials exhibit, for instance, intrinsic mechanical properties and not those dominated by voids. 

The pulsed electrodeposition technique (PED) is a versatile method for the preparation of nanostructured metals and alloys [47]. In the last two decades PED has received much attention worldwide because it allows the preparation of large bulk samples with high purity, low porosity and enhanced thermal stability. 

The bath composition, the pH-value, the hydrodynamic conditions and also the use of special current pulse shapes are further possibilities to influence the deposition process. It is advantageous to perform the pulsed electrodeposition in the galvanostatic mode because the average deposition rate can be simply derived from... 

Usually there is a lot of effort required to make nanomaterials by electrochemical means. In aqueous solutions the electrodeposition of nanocrystalline metals requires pulsed electrodeposition and the addition of additives whose reaction mechanism hitherto has only been partly understood (see Chapter 8). A further shortcoming is that usually a compact bulk material is obtained instead of isolated particles. The chemical synthesis of metal or metal oxide nanoparticles in aqueous or organic solutions by colloidal chemistry, for example, also requires additives and often the desired product is only obtained under quite limited chemical conditions. Changing one parameter can lead to a different product. 

To reduce the noble metals content in the electrode and to increase the catalyst activity, the electrode preparation by deposition of Pd, Ni, Bi and La on the surface of Pt/C catalyst [6], as well as the deposition of Ru and Mo on platinum by pulse electrodeposition at appropriate potentials have been elaborated [7]. 

Somasundaram, S., Chenthamarakshan, C. R., de Tacconi, N. R., Basit, N. A. and Rajeshwar, K. (2006). Composite W03-Ti02 films Pulsed electrodeposition from a mixed bath versus sequential deposition from twin baths. Electrochem. Commun. 8(4), 539-543. 

Models of deposition-rate distribution and shape change are likely to evolve in new directions as progress continues in the areas of alloy plating [76], electrodeposition of resists [77, 78], electrodeposition of composite materials [79], electrodeposited eompositionally modulated alloys [80], pulsed electrodeposition, and patterned electroless plating [81]. The success of electrodeposition in high-technology device fabrication will continue to depend on the degree to which rate-distribution effects can be understood, predicted, and controlled. 

Several studies were published in recent years on electrodeposition of W-Co alloys. Donten and Stojek used pulse electrodeposition to increase the tungsten content in amorphous Co-W alloys. These alloys contained, in addition, small amounts of boron or phosphorous. They showed that, if a symmetrical current pulse was used, the tungsten content in the alloys reached a maximum value of 41.4 at.%, which is higher than in the case of direct current deposition. However, when using any asymmetrical... 

Brankovic SR et al (2006) Pulse Electrodeposition of 2.4 T Co Fe alloys at nanoscale for magnetic recording application. IEEE Trans Magn 42 132-139... 

Synthesis of arrays of BiTe nano-wires by electrodeposition has been studied by different authors [63-66]. Li et al. employed pulsed electrodeposition into the nanochannels of porous anodized alumina membranes to fabricate nano-wire arrays of Be TCj [63]. The anodized alumina membrane with the pore sizes of about 40 and 60 nm were used. A 200 nm thick layer of Au film was sputtered onto one side of the anodized alumina membrane to serve as the working electrode in a two-electrode plating cell, and a graphite plate was used as the counter-electrode. 

H. (2011) In vitro dissolution and corrosion study of calcium phosphate coatings elaborated by pulsed electrodeposition current on Ti6A14V substrate. J. Mater. Sci. Mater. Med., 22, 753-761. 

Gopi, D., Khartika, A., Nithya, S., Kavitha, L. (2014) In vitro biological performance of mineral substituted hydroxyapatite coating by pulsed electrodeposition method. Mater. Chem. Phys., 144 (1-2), 75-85. 

From libraries of pulsed electrodeposited platinum (Pt) doped WO3, whereby a new means of creating nanoparticles has been developed. The nanoparticles show high activity for methanol oxidation without the poisoning problems of Pt... 

Nano-particulate tungsten oxide films were also synthesized by pulsed electrodeposition in libraries. Particle sizes between 45 330 nm were achieved by varying pulse duration from 5 ms to 500 ms. Films prepared by continuous electrodeposition had an average particle size of approximately 375 nm. As the pulse time decreased, particle size decreased as well. For a 5 msec pulsed deposition, the average particle size was approximately 45 nm. We checked the particle size with respect to deposition time (30 sec to 30 min, that is 3,000 to 180,000 pulses) and found that particle size was independent of total number of pulses the total number of pulses seemed to affect only film thickness and not the final particle size. 

High-concentration (40 weight percent [wt%]) ternary Pt alloy samples prepared using the carbothermal technique have yielded surface area and activity values comparable to commercial Pt samples. Platinum/Carbon (Pt/C) prepared by pulse-electrodeposition showed superior surface area and activity when compared to direct current deposited Pt/C electrodes. 

At the University of South Carolina, Pt/C electrodes were fabricated by using direct current (DC) and pulse current electrodeposition methods. With the use of current pulses rather than DC, a higher deposition current density could be used and Pt deposits with a higher surface area were possible. Figure 3 compares the polarization performance of electrodes prepared by pulse electrodeposition (current density=50 mA/cm and duty cycle=0.25) and DC deposition. Electrodes fabricated under pulse deposition conditions display better performance than the DC-plated electrode. The best performance is obtained when the ON time is 100 ms and OFF time is 300 ms. 

FORMATION OF METAL NANOWIRES ARRAYS BY PULSED ELECTRODEPOSITION... 

Nanowires of various metal were embedded into porous anodic alumina by pulsed electrodeposition. Pores of alumina were filled with Cd, Zn, In, Cu, Ag, In, Ni, Co, Sn,... 

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