The invention discloses a composite catalyst for preparing
acrylic acid through selective oxidation of propylene and a preparation method of the composite catalyst, and relates to the technical field of
acrylic acid synthesis, and the preparation method of the catalyst comprises the following steps: (1) fully mixing pseudo-
boehmite, aluminum
hydroxide, a
magnesium compound, a reinforcing agent and a pore forming agent to form a mixture, adding
nitric acid into the mixture, forming a wet gel blank with
plasticity;
drying,
grinding and sieving the wet gel blank, and then carrying out segmented
calcination and
nitric acid treatment to obtain a
magnesium aluminate spinel carrier; and (2) preparing a
salt solution from
metal salts containing Mo, V, Cu, Ni, Ce and La, adding
ammonia water to prepare a complexing solution, loading the
metal in the
slurry onto a carrier by a ball milling method, carrying out surface boronizing treatment,
drying, and calcining to obtain the active catalyst. The prepared catalyst has good
acrylic acid selectivity in one-step propylene oxidation preparation of acrylic acid, and also has very high
mechanical strength and better stability.