Reduction of Ni2+-Al3+ and Cu2+-Al3+ Layered Double Hydroxides to Metallic Ni0 and Cu0 via Polyol Treatment

Abstract

The reduction of nickel (Ni2+) and copper (Cu2+) to their metallic forms is reported for Ni-Al and Cu-Al layered double hydroxides (LDHs). Ethylene glycol is used as the reducing agent (the so-called polyol process). The degree of reduction of both cations was found to be dependent on the time and temperature of treatment and the nature of the anions located between the hydroxide layers. The process was found to be more efficient in reducing Cu2+ than Ni2+; substantial reduction of Cu2+ was obtained after 3 h at 200°C, whereas the Ni2+ is not completely reduced after 192 h of treatment at this temperature.