V. K. Puthiyapura et al., Journal of Power Sources, 269 (2014), pp. 451-460, describe the preparation of an ATO-supported IrO₂ catalyst via a so-called Adams fusion method, wherein H₂IrCl₆ and NaNO₃ are added to an aqueous dispersion of antimony-doped tin oxide (ATO) particles. The solvent is evaporated and the obtained mixture is dried and calcined at 500° C. By this Adams fusion method, a composition of relatively low electrical conductivity is obtained, as shown by FIG. 6 of said publication. Emma Oakton et al., New J. Chem., 2016, 40, pp. 1834-1838, describe the preparation of a high surface area iridium oxide/titanium oxide composition via the Adams fusion method by dissolving a Ti salt, an Ir salt and NaNO₃ in water, evoparating the water, drying the mixture, followed by calcination at 350° C. A composition of relatively low electrical conductivity is obtained, as shown by FIG. 4 of said publication.

EP 2 608 297 A1 describes a catalyst composition for water electrolysis, comprising iridium oxide and a high surface area inorganic oxide, having a BET surface area in the range of 30 to 200 m²/g, wherein the inorganic oxide is present in an amount of from 25 to 70 wt % based on the total weight of the catalyst and wherein the electrical conductivity of the catalyst is >0.01 S/cm.

The object of the present invention is to provide a composition which is an effective electrocatalyst, in particular for the oxygen evolution reaction, shows high stability under very corrosive conditions (e.g. in PEM water electrolysers or PEM fuel cells), and is viable from an economical point of view.