Catalytic Properties of Silver Vanadium Phosphates in <i>n</i>‐Butane Oxidation – Considerations on the Impact of the [V_xO_y] Substructure

Abstract Catalysts based on silver vanadium phosphates with a general chemical formula Ag 2 VP x O d (1 ≤ x ≤ 2; 6 ≤ d ≤ 8) have been prepared and tested in gas phase oxidation of n ‐butane. This general chemical formula comprises the two known phosphates Ag 2 (V V O 2 )PO 4 ( x = 1; d = 6) and Ag 2 (V IV O)P 2 O 7 ( x = 2; d = 8) and one novel compound with an approximate composition Ag 2 V IV,V P 1.6 O 7+δ (0 ≤ δ ≤ 0.5). Among the prepared compounds, Ag 2 (V V O 2 )PO 4 shows the highest activity while Ag 2 (V IV O)P 2 O 7 is completely inactive. The novel phase Ag 2 V IV,V P 1.6 O 7+δ (0 ≤ δ ≤ 0.5) is the only compound with selectivity to maleic anhydride. A structure‐property relationship for the prepared catalysts is discussed.