Electrodeposition of photocatalytic AlInSb semiconductor alloys in the Lewis acidic aluminum chloride−1-ethyl-3-methylimidazolium chloride room-temperature ionic liquid

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, ∼ 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.