An inorganic material is described, which consists of at least two elementary spherical particles, each one of said spherical particles comprising metallic nanoparticles of size ranging between 1 and 300 nm and a mesostructured matrix based on an oxide of at least one element X selected from the group made up of silicon, aluminium, titanium, tungsten, zirconium, gallium, germanium, tin, antimony, lead, vanadium, iron, manganese, hafnium, niobium, tantalum, yttrium, cerium, gadolinium, europium and neodymium, and the mixture of at least two of these elements, said mesostructured matrix having a pore diameter ranging between 1.5 and 30 nm and having amorphous walls of thickness ranging between 1 and 30 nm, said elementary spherical particles having a diameter D greater than 10 μm and less than or equal to 100 μm. Said material can also contain zeolite nanocrystals trapped within said mesostructured matrix.