A material is described in the form of a millimetric article constituted by coarse alumina particles with a median diameter in the range 10 to 200 μm, said coarse particles being at a distance, from one interface to another, of less than 10 μm, fine alumina particles with a median diameter in the range 0.5 to 10 μm, said fine particles being at a distance, from one interface to another, of less than 5 μm and being located in the space between the coarse particles, and a binder constituted by aluminium phosphate, said binder being located in the space between said fine and coarse particles, said material having a mesoporous volume, measured by mercury porosimetry, in the range 0.2 to 2 mL/g, a macroporous volume, measured by mercury porosimetry, in the range 0.05 to 0.2 mL/g and a BET specific surface area in the range 80 to 350 m2/g.