Hybrid membranes containing titanium dioxide doped with fluorine

Hybrid membranes based on crystalline titanium dioxide containing fluorine atoms within the crystalline lattice comprising atoms of titanium and oxygen are described; these hybrid membranes are particularly suitable for the production of fuel cells and electrolysers. The titanium dioxide contained in them may be produced by a process comprising the following stages: a) a titanium core is reacted with a NH4HF2 aqueous solution of; b) the aqueous dispersion so obtauned is filtered with subsequent separation of a solid residue and an aqueous solution containing titanium salts; c) the aqueous solution so obtained is subjected to hydrolysis, said hydrolysis comprising a first stage at pH 6.5-8.0 and a second stage at pH 9-11; d) the aqueous dispersion thus obtained is filtered and the solide residue is subjected to pyrohydrolysis at a maximum temperture of approximately 500°C, preferably approxiamtely 450°C.