In the field of catalyst support and adsorption, mesoporous petal-like MgAl₂O₄ has attracted much attention because of their large surface area, abundant and accessible catalytic sites and not easy to aggregate. Mesoporous petal-like MgAl₂O₄ was prepared by a molten salt assisted non-hydrolytic sol–gel method with aluminum wire as aluminum source, magnesium powder as magnesium source, absolute ethyl alcohol as a solvent and Na₂MoO₄ as a molten salt, respectively. The effects of heat treatment temperature and soaking time on the phase composition and morphology of petal-like MgAl₂O₄ were investigated by X-ray diffraction and field emission scanning electron microscopy. The microstructure of the petal-like MgAl₂O₄ was determined by transmission electron microscopy (TEM), and the specific surface area and pore volume were measured by N₂ adsorption–desorption analysis. The results show that heat treatment temperature and soaking time both have an influence on the morphology. MgAl₂O₄ prepared has a petal-like morphology with a length of 140–160 nm when the heat treatment temperature and time are 900 ℃ and 8 h. The specific surface area of the prepared MgAl₂O₄ is 76 m²/g. Based on the results by TEM and N₂ adsorption–desorption analysis, the petal-like MgAl₂O₄ exhibits a mesoporous structure. This work paves a promising approach to prepare mesoporous petal-like MgAl₂O₄.

CeO₂ nanosheets were directly synthesized by a precipitation process with the aid of 1-butyl-3-methyl-imidazolium ionic liquids at room temperature. The anion species and the concentration of the room temperature ionic liquids (RTILs) have a great influence on the morphology of the resulting products. The as-prepared CeO₂ is irregular and agglomerated seriously in the absence of RTILs, while it changes from nanocube to nanosheet with increasing the RTIL concentration or decreasing the polarity and hydrophilicity in the orders [Bmim]Cl > [Bmim]Br > [Bmim]BF₄ > [Bmim]PF₆. The CeO₂ nanocubes have relatively uniform grain size distribution with size of 4.5–6.4 nm, and the nanosheets are assembled by a great deal of nanocrystalline whose length and width extend to hundreds of nanometers. The as-synthesized CeO₂ exhibits an excellent removal capacity for the organic pollutant Congo red dye, indicating its potential use in practical wastewater treatment.