A process for the preparation of an inorganic material with a hierarchical porosity in the micropore and mesopore domains, said material being constituted by at least two elementary spherical particles having a maximum diameter of 200 microns, each of said spherical particles comprising metallic particles that have a mean size greater than or equal to 0.6 nm and strictly less than 1 nm, and contain at least one or more metals selected from vanadium, niobium, tantalum, molybdenum, tungsten, iron, copper, zinc, cobalt and nickel, said metallic particles being trapped within a matrix in a homogeneous and uniform manner, wherein said matrix is mesostructured, based on silicon oxide, having microporous walls with a thickness in the range 1 to 60 nm, wherein said matrix is constituted either wholly by proto-zeolitic entities, or wholly by zeolitic entities or by a mixture of proto-zeolitic entities and zeolitic entities, said process comprising at least the following steps: a) preparing a solution containing zeolitic nanocrystals with a maximum nanometric dimension equal to 60 nm based on silicon and/or precursor elements of proto-zeolitic entities based on silicon; b) mixing, in solution, said metallic particles or at least one metallic precursor of said metallic particles, at least one surfactant and at least said solution obtained in accordance with a) such that the ratio of the volumes of inorganic and organic materials, V inorganic /V organic, is in the range 0.29 to 0.50; c) aerosol atomization of said solution obtained in step b) in order to result in the formation of spherical droplets; d) drying said particles; g) eliminating at least said template and at least said surfactant h) eliminating at least said template and at least said surfactant regenerating said metallic particles in the form of a polyoxometallate which may have decomposed during step g) by washing the solid obtained from said step g) with a polar solvent for a period of 1 to 24 hours, i) drying step i) that is carried out at a temperature in the range 40°C to 100°C for a period in the range 12 to 48 hours, wherein said metallic particles are in the form of a polyoxometallate with formula (X x M m O y H h) q-, where H is a hydrogen atom, O is an oxygen atom, X is an element selected from phosphorus, silicon, boron, nickel and cobalt and M is one or more elements selected from vanadium, niobium, tantalum, molybdenum, tungsten, iron, copper, zinc, cobalt and nickel, x being equal to 0, 1, 2, or 4, m being equal to 5, 6, 7, 8, 9, 10, 11, 12 or 18, y being in the range 17 to 72, h being in the range 0 to 12 and q being in the range 1 to 20 (y, h and q being integer numbers). a) preparing a solution containing zeolitic nanocrystals with a maximum nanometric dimension equal to 60 nm based on silicon and/or precursor elements of proto-zeolitic entities based on silicon; b) mixing, in solution, said metallic particles or at least one metallic precursor of said metallic particles, at least one surfactant and at least said solution obtained in accordance with a) such that the ratio of the volumes of inorganic and organic materials, V inorganic /V organic, is in the range 0.29 to 0.50; c) aerosol atomization of said solution obtained in step b) in order to result in the formation of spherical droplets; d) drying said particles; g) eliminating at least said template and at least said surfactant h) eliminating at least said template and at least said surfactant regenerating said metallic particles in the form of a polyoxometallate which may have decomposed during step g) by washing the solid obtained from said step g) with a polar solvent for a period of 1 to 24 hours, i) drying step i) that is carried out at a temperature in the range 40°C to 100°C for a period in the range 12 to 48 hours,