Synthesis and characterization of layered and hexagonal nickel–aluminum oxides

Layered and hexagonal mesostructures of nickel–aluminum oxides templated by alkyl sulfate assemblies were synthesized for the first time by the homogeneous precipitation method using urea. X-ray diffraction patterns and transmission electron microscopy (TEM) proved that there was a transformation from layered to hexagonal mesostructure within a prolonged time of 20 h. The Brunauer–Emmett–Teller surface area was reported after solvent extraction and calcinations at a large range of temperatures. The mesostructured hexagonal solid by the anion-exchange with acetate species results in a mesoporous material with a specific surface area of as large as 277 m2 g−1. The specific surface area decreased from 299 to 71 m2 g−1 as the temperatures of calcination increasing from 523 to 1033 K.