The electrodeposition of AlIn, AlSb, and AlInSb alloys was examined at copper rotating wire electrodes in the Lewis acidic 66.7-33.3 mol.% (m/o) aluminum chloride-1-ethyl-3-methylimidazolium chloride room-temperature ionic liquid. The Sb content in the AlSb binary electrodeposits depended on the applied current density, but the In content in the AlIn alloys was quite low, similar to 1 at.% (a/o), and independent of the current density. Variation of the partial current densities for the In and Sb during AlInSb deposition suggested that the deposition of a second phase rich in In and Sb, possibly InSb, occurs simultaneously at higher applied current densities. However, no X-ray diffraction patterns are apparent in these deposits other than that for face-centered cubic Al. Thus, the AlInSb deposit most likely consists of a non-equilibrium mixture of Al(x)In(y)Sb(100-x-y) and amorphous or nanocrystalline InSb. The AlInSb alloy semiconductor deposits prepared during this investigation exhibited photocatalytic behavior and could catalyze the photodecomposition of water under illumination with visible light. (C) 2007 Elsevier B.V. All rights reserved.