The present invention relates to a selective catalytic reduction catalyst for the treatment of an exhaust gas of a diesel engine comprising (i) a flow-through substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the flow-through substrate extending therethrough; (II) a coating disposed on the surface of the internal walls of the substrate, where-in the surface defines the interface between the passages and the internal walls, wherein the coating comprises a vanadium oxide supported on an oxidic material comprising titania, and further comprises a mixed oxide of vanadium and one or more of iron, erbium, bismuth, cerium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium, yttrium, molybdenum, tungsten, manganese, cobalt, nickel, copper, aluminum and antimony.