Tyre for vehicle wheels

A process for producing iron oxide and/or aluminium oxide catalysts substantially free of Co, Ni, and Mo comprising:

• preparing an aqueous solution (i) comprising a Fe3+ soluble salt and an Al3+ soluble salt, wherein the solution (i) comprises a molar concentration of Fe3+ ranging from 0.3 to 1.5 M and a molar concentration of Al3+ ranging from 0.8 to 2.4 M,
• preparing an aqueous solution (ii) comprising ammonium hydroxide, wherein the solution (ii) comprises a molar concentration of NH3 ranging from 1.8 to 18 M,
• adding solution (ii) to solution (i), wherein an amount of NH3 added per minute ranges from 1.3·10−4 to 4.5·10−1 moles per total moles of iron or aluminium or both iron and aluminium, resulting in a combined solution with a pH ranging from 6 to 8, wherein a gel of the combined solution forms,
• drying the gel at a temperature ranging from 35° C. to 100° C. to obtain a solid, and
• calcining the obtained solid at a temperature ranging from 250° C. to 750° C. under an atmosphere chosen from air and nitrogen.