Process for preparing a catalyst for the oxidation and ammoxidation of olefins

A process for preparing an antimonate-based mixed metal oxide catalyst in a catalytically active oxidized state, wherein the catalyst is represented by the empirical formula Me_aSb_bX_cQ_dR_eO_f, wherein Me, X, Q, R, a, b, c, d, e, and f are as defined herein, comprising (a) contacting an aqueous Sb₂O₃ slurry with HNO₃ and one or more Me compounds, and, optionally, one or more compounds selected from X, Q, or R compounds to form a first mixture; (b) heating and drying the first mixture to form a solid product; and (c) calcining the solid product to form the catalyst, the catalysts prepared by the process, and the use of the catalysts in ammoxidation and oxidation processes. The catalysts of the invention are particularly useful for the production of acrylonitrile from propylene, ammonia, and an oxygen-containing gas.