An inorganic material is described that is composed of at least two elementary spherical particles, each of said spherical particles comprising metallic nanoparticles having a size between 1 and 300 nm and a mesostructured matrix based on an oxide of at least one element X chosen from the group composed 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 between 1.5 and 30 nm and having amorphous walls of thickness 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 may also contain zeolite nanocrystals trapped within said mesostructured matrix.