Synthesis and characterization of mesostructured alumina prepared in the presence of dodecylphosphate

摘要

The present study focuses on the mechanisms of formation of two dodecylphosphate (DDP)mesostructured alumina synthesized at pH = 5 and 8. Although the materials are both lamellar, theirmorphology, chemical composition and local structure are very different. Their mechanism pathwayalso differ. In the material synthesized under acidic conditions, the surfactant is in strong interactionwith the alumina layers. Indeed, NMR experiments seem to indicate the presence of Al-O-P bonds.The material would be of aluminophosphate type rather than a pure alumina. For the samplesynthesized under basic conditions, chemical analyses showed the incorporation of large amounts ofsodium. In this case, the interactions between the surfactant and the alumina framework are weakand the mechanism of formation would be of S-M~+I° type, where S is the surfactant (DDP), M thecounterion (Na~+) and I the inorganic framework (alumina).