Underpotential deposition of aluminum and alloy formation on polycrystalline gold electrodes from AlCl3/EMIC room-temperature molten salts

Interfacial processes occurring at polycrystalline gold in acidic 1-ethyl-3 -methytimidazolium chloroaluminate melts at room temperature, at potentials more positive than aluminum bulk deposition, include both Al underpotentia l deposition and the formation of Al/Au alleys. This information complement s that reported in the literature for Al electrodeposition on Au in AlCl3/N aCl melts at temperatures of 200 degrees C and higher. Cyclic voltammetry a nd chronopotentiometry suggest that at least two alloys farm, and there is fast phase transformation between these intermetallic compounds at room tem perature in the aluminum underpotential region. This transformation with th in gold films was slower than that in bulk gold electrodes. (C) 2000 The El ectrochemical Society. S0013-4651(99)07-009-3. All rights reserved.