TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The process comprises: (i) depositing a composite material comprising at least one refractory metal and at least one non refractory filling metal on the substrate, at a temperature of 50-250 degrees C; (ii) oxidizing the composite material; (iii) eliminating non-refractory filling metal oxide obtained in step (ii), by selective chemical etching; and (iv) heat annealing at a temperature of greater than or equal to 600 degrees C, preferably greater than or equal to 650 degrees C. The process comprises: (ia) depositing, on the substrate, at a temperature of 50-250 degrees C, a composite material consisting of at least one refractory metal and at least one non-refractory filling metal, (iia) removing, by selective chemical etching, of the non refractory filling metal obtained in step (ia), (iiia) chemical oxidation or heat treatment under oxidizing atmosphere, (iva) heat annealing at a temperature of greater than or equal to 600 degrees C, preferably greater than or equal to 650 degrees C. The process comprises: (iaa) the depositing step, (iiaa) removing, by selective chemical etching, of the non refractory filling metal obtained in step (iaa), and (ivaa) thermal annealing in an oxidizing atmosphere at a temperature of 10 to above 600 degrees C, preferably greater than or equal to 650 degrees C. The deposition of the composite material is carried out at a temperature of 50-150 degrees C, by sputter deposition or thermal spraying or electrolyte deposition. The step of elimination by selective chemical etching is contacting the substrate coated with the composite material with an acidic or basic solution, preferably solutions of phosphoric acid (H3PO4), sodium carbonate (NaCO3), potassium hydroxide (KOH) and sodium hydroxide (NaOH). The oxidation step is a step of thermal, chemical or electrochemically oxidation. The oxidation step is an electrochemical oxidation, which is carried out by immersing the composite material in an aqueous acid having a concentration of 0.1-3 mole/l-1 at a temperature of 40-70 degrees C, then by applying a current density of 1-15 mAx cm-2 to obtain a potential of 70-250 V. The step (iiia) of oxidizing chemical treatment or heat treatment in the oxidizing atmosphere is either a chemical oxidation step performed in an oxidizing bath having sulfuric acid/hydrogen peroxide or hydrochloric acid/hydrogen peroxide base, or a thermal oxidation step carried out at a temperature of 400-500 degrees C, where the temperature of step (iiia) is less than the temperature of step (iva) of heat annealing, by introducing molecular oxygen at a pressure of 100 mbar to 1 bar. The step (iva) of heat annealing in oxidizing atmosphere is carried out by introducing molecular oxygen at atmospheric pressure. The pore walls have a thickness of 1-7 nm. The refractory metal oxide is titanium oxide, tungsten oxide, niobium oxide, and/or molybdenum oxide. The ultra-porous photocatalytic material has: a porosity of 50-95%; a specific surface of 500-700 m2x cm-3, preferably 600-700 m2x cm-3; and a thickness of greater than 2 mu m, preferably 8-100 mu m. Preferred Components: The refractory metal is titanium, tungsten (both preferred), niobium, and/or molybdenum, and non refractory filling metal is aluminum (preferred), and/or silicon. The atomic percentage of refractory metal in the composite material is 20-70%. The substrate is glass, metal, polymers, ceramics and semiconductor materials.