Catalyst having a silver vanadium oxide and a promoter phase

Disclosed is a catalyst with a catalytically active composition which comprises a phase A and a phase B in the form of three isolated areas, wherein the phase A is a silver vanadium oxide bronze, and the phase B is a mixed oxide based on titanium dioxide and vanadium pentoxide. The catalyst used for the production of aldehydes, carboxylic acids and / or carboxylic anhydrides from aromatic or heteroaromatic hydrocarbons by gas phase oxidation.