Pulsed electrodeposition

The fundamental basis of the sonoelectrochemical technique to form nanoparticles is massive nucleation using a high current density electrodeposition pulse (ca. 150-300 mA cm ), followed by removal of the deposit from the sonoelectrode by the sonic pulse. Removal of the particles from the electrode before the next current pulse prevents crystal growth. Overall there are many experimental variables involved in sonoelectrochemical deposition electrolyte composition and temperature, electrodeposition conditions including current density (le), pulse-on time (te(on)) and ratio between pulse-on time and pulse-off time (te(off)) (the duty cyde) sonic probe conditions sonic power (Is), sonic pulse parameters, fs(on) and ts(off). 

There are three types of electrolytic metal deposition processes direct current electrodeposition, pulse plating, and laser-induced metal deposition. ... 

Pulse electrodeposition (pulsed potential or pulsed current) has been also employed for CdSe formation [30]. In addition, EC-ALE has been employed for the electrochemical synthesis of CdSe on Au substrates through the layer-by-layer UPD of Se and Cd in sequence [45,46]. 

To overcome some of the problems associated with aqueous media, non-aqueous systems with cadmium salt and elemental sulfur dissolved in solvents such as DMSO, DMF, and ethylene glycol have been used, following the method of Baranski and Fawcett [48-50], The study of CdS electrodeposition on Hg and Pt electrodes in DMSO solutions using cyclic voltammetry (at stationary electrodes) and pulse polarography (at dropping Hg electrodes) provided evidence that during deposition sulfur is chemisorbed at these electrodes and that formation of at least a monolayer of metal sulfide is probable. Formation of the initial layer of CdS involved reaction of Cd(II) ions with the chemisorbed sulfur or with a pre-existing layer of metal sulfide. 

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

Babu SM, Dhanasekaran R, Ramasamy P (1991) Electrodeposition of CdTe by potentiostatic and periodic pulse techniques. Thin Solid Films 202 67-75... 

Lokhande CD (1987) Pulse plated electrodeposition of CulnSe2 films. J Electrochem Soc 134 1727-1729... 

A novel method called pulsed light assisted electrodeposition (PLAE), involving the alternate depositions of two elements to form a compound semiconductor, one by electrochemical and the other by photoelectrochemical deposition, should be referred to in this context. Takahashi et al. [108] suggested that high-quality... 

Fig. 4.11 Schematic representation of the pulsed light assisted electrodeposition of CdTe. (a) Deposition of one Te monolayer in the dark (b) deposition of one Cd monolayer under illumination. (Reproduced with permission from [108], Copyright 2009, American Institute of Physics)...

Takahashi M, Todorobaru M, Wakita K, Uosaki K (2002) Heteroepitaxial growth of CdTe on a p-Si(lll) substrate by pulsed-light-assisted electrodeposition. Appl Phys Lett 80 2117-2119... 

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. 

Fig. 19. Sampled-current voltammogram constructed from the current-time transients that resulted from a series of potential-step experiments at a stationary Pt electrode in a 35.0 x 10 3 mol L-1 solution of Ni(II) in the 66.7 m/o AlCl3-EtMeImCl melt ( ) total current, ( ) partial current for the electrodeposition of Ni, (O) partial current for the electrodeposition of Al. The total current was sampled at 3 s after the application of each potential pulse. Adapted from Pitner et al. [47] by permission of The Electrochemical Society. 

Batley [28] examined the techniques available for the in situ electrodeposition of lead and cadmium in estuary water. These included anodic stripping voltammetry at a glass carbon thin film electrode and the hanging drop mercury electrode in the presence of oxygen and in situ electrodeposition on mercury coated graphite tubes. Batley [28] found that in situ deposition of lead and cadmium on a mercury coated tube was the more versatile technique. The mercury film, deposited in the laboratory, is stable on the dried tubes which are used later for field electrodeposition. The deposited metals were then determined by electrothermal atomic absorption spectrometry, Hasle and Abdullah [29] used differential pulse anodic stripping voltammetry in speciation studies on dissolved copper, lead, and cadmium in coastal sea water. 

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