Described is a process for the preparation of a catalyst. The process comprises (i) providing a substrate which is optionally coated with one or more coating layers; (ii) impregnating one or more particulate support materials with one or more platinum group elements; (iii) adding one or more alkaline earth elements and one or more solvents to the product obtained in step (ii) to obtain a slurry; (iv) adjusting the pH of the slurry obtained in step (iii) to a value ranging from 7 to 10 (v) adjusting the pH of the slurry to a value ranging from 2 to 6; (vi) optionally milling the slurry obtained in step (v); (vii) providing the slurry obtained in step (vi) onto the optionally coated substrate in one or more coating steps. Describes is as a catalyst which is obtainable according to said process and its use in the treatment of exhaust gas.