Synthesis and Surface Reactivity of Nanocomposite Support Al2O3/α-Al2O3

A simple method leading to the preparation of homogeneous macroporous high surface area alumina composites is presented in this work. A simple incipient wetness impregnation of aluminum nitrate on α-Al 2 O 3 leads to high surface area macroporous composites. The impregnated phase is however not homogeneously dispersed on the support porosity, e.g. an important fraction of the α-Al 2 O 3 crystals remains free from the impregnated phase. A high dispersion of the impregnated phase is obtained after a supplementary step of basic impregnation. After this step, the impregnated phase completely covers the surface of the support, leading to highly homogeneous composites. Moreover, a precise control of the pH was found to be the key factor to control the morphology of the impregnated phase, and then the physical properties of the composites.