Particles suitable for catalyzing oxygen reduction or hydrogen oxidation and being proton-conducting by grafting specific proton-conducting fluorinated polymers to the surface thereof

Particles comprising a material for catalysing oxygen reduction or hydrogen oxidation and being grafted by grafts having the following formula (III):

• a curly bracket indicating the location at which the grafts are bound in a covalent manner to the particles in which:
• R1 represents an organic spacer group;
• Z represents a single bond or an organic spacer group;
• R2 represents a halogen atom;
• Y1 corresponds to a repeating unit resulting from polymerisation of a fluorinated styrenic monomer, and n1 corresponds to a number of repetitions of the repeating unit placed within parentheses, this number of repetitions being a positive integer that is at least equal to 2;
• Y2 corresponds to a repeating unit resulting from polymerisation of a non-fluorinated styrenic monomer bearing at least one proton-conducting group, and n2 corresponds to a number of repetitions of the repeating unit placed within parentheses, this number of repetitions being equal to 0 or being a positive integer that is at least equal to 2;
• and the group —Z—(Y1)n1—(Y2)n2—R2, which intersects a carbon-carbon bond of the phenyl group, signifying that it can be bound to any one of the carbon atoms of the phenyl group.