New reflections appear in the powder X-ray diffraction patterns of Ni-Al-Cl LDH films that have been subjected to repeated voltammetric scans in basic electrolytes (pH >= 12). They are attributed to the formation of new phases, one of which is beta-Ni(OH)(2). The intensities of the d(003), and d(006) reflections of the LDH layer were also reduced. This was not observed for Ni-Al-Cl LDH films that were simply soaked in basic solutions or cycled in pH 8 buffer electrolyte solutions. The XRD pattern of Ni-Al-CO3 LDH films was not affected by voltammetric scanning in basic electrolyte. (c) 2005 Elsevier B.V. All rights reserved.