Using nitrates as precursors, a series of three-dimensionally ordered macroporous (3DOM) materials, such as Al₂O₃, CeO₂, Cr₂O₃, NiO, MgO, In₂O₃, CeO₂/Al₂O₃, Cr₂O₃/ Al₂O₃ and NiO/Al₂O₃, have been successfully fabricated. The role of alcohol and citric acid in the precursors has been described. Especially, the addition of citric acid may significantly improve the formation of 3DOM skeleton. SEM observation indicates that in the materials the macropores are arrayed highly periodically and connected each other by small windows, showing a super-cage morphology structure with diameter of several hundred nanometers. XRD and TEM determination show that walls consisted of the nanoparticles. The particle crystal size was increased along with increase of the calcination temperature, which can finally cause the destruction of the ordered macroporous structure at higher calcination temperature. This study indicates that the nitrate route to the preparation of 3DOM materials is a novel and convenient approach.

Key words: three-dimensionally ordered macropore, nitrate, metal oxide, PS colloidal crystal