The electrochemistry of metals in room-temperature chloroaluminate molten salts

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7283746

Xu, Xiao-Hong

The room-temperature chloroaluminate molten salt, aluminum chloride-1-methyl-3-ethylimidazolium chloride has proven to be useful electrolyte for the electrodeposition and electrodissolution of metals. The electrodeposition of lead, tin, silver, gold, and mercury was studied in this melt. Evidence for the underpotential deposition of lead and silver in acidic (66.7-33.3 mol%) melt and tin in acidic and basic (44.4-55.6 mol%) melt was found at polycrystalline gold. Nucleation overpotentials were observed for the deposition of mercury on gold in basic melt. The deposition of lead and silver from acidic melt and the deposition of gold from basic melt on glassy carbon involves progressive 3-D nucleation on a large number of active sites with hemispherical diffusion-controlled growth of the nuclei. The deposition of tin and and mercury from acidic melt exhibits progressive 3-D nucleation on a finite number of active sites. The deposition of tin and mercury from basic melt on glassy carbon involves instantaneous 3-D nucleation. The electrode-position of lead and silver from acidic melt on tungsten involves instantaneous 3-D nucleation, whereas the electrodeposition of gold and mercury from basic melt exhibits 3-D progressive nucleation. The deposition of lead and silver from acidic melt and the deposition of tin from both acidic and basic melt on platinum does not exhibit obvious evidence for either UPD or nucleation. The electrodeposition of gold and mercury on platinum from basic melt involves progressive 3-D nucleation. The voltammetric oxidation of Sn(II) to Sn(IV) is hindered by the weak adsorption of Sn(II). Sn(IV) is complexed as [SnCl[sub 6]][sup 2[minus]] in basic melt. The voltammetric reduction of gold(III) at glassy carbon and platinum in basic melt produces an intermediate gold(I) species. The reduction of Hg[sup 2+] in acidic melt involves two steps, whereas the reduction of [HgCl[sub 2+p]][sup p[minus]] in basic melt proceeds by a single two-electron step.

• Research Organization: Mississippi Univ., University, MS (United States)
• OSTI ID: 7283746
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMBIENT TEMPERATURE
CHALCOGENIDES
CHEMICAL COATING
CHEMICAL REACTIONS
CHEMISTRY
CHLORINE COMPOUNDS
DEPOSITION
ELECTROCHEMICAL COATING
ELECTROCHEMISTRY
ELEMENTS
HALOGEN COMPOUNDS
METALS
MOLTEN SALTS
NUCLEATION
OXIDES
OXYGEN COMPOUNDS
PH VALUE
SALTS
SURFACE COATING