COMPOSITE OXIDE CATALYST AND METHOD FOR PRODUCING SAME

A method for producing a composite oxide catalyst that contains a composite oxide represented by the compositional formula Mo₁V_aSb_bNb_cW_dZ_eO_n (in the formula, component Z denotes an element such as La, Ce, Pr, Yb, Y, Sc, Sr or Ba, the values of a, b, c, d, e and n are such that 0.1 ≤ a ≤ 0.4, 0.1 ≤ b ≤ 0.4, 0.01 ≤ c ≤ 0.3, 0 ≤ d ≤ 0.2, 0 ≤ e ≤ 0.1, and the a/b and a/c atomic ratios are such that 0.85 ≤ a/b < 1.0 and 1.4 < a/c < 2.3), wherein the production method includes the following steps: a step of preparing a specific raw material preparation that contains Mo, V, Sb, Nb, W and Z; a step of drying the raw material preparation so as to obtain a dried powder; a step of subjecting the dried powder to preliminary firing so as to obtain a preliminarily fired body; a step of subjecting the preliminarily fired body to main firing so as to obtain a fired body having protrusions on the surface of particles; and a step of removing the protrusions by means of an air stream. The reduction rate of the preliminarily fired body is 8 to 12% and the specific surface area of the fired body is 7 to 20 m²/g.