Fluid catalytic cracking catalysts for increasing butylene yields

A method of making a microspherical fluid catalytic cracking catalyst, the method comprising:

• mixing microspheres with a barium solution to form a barium-microsphere mixture;
• and
• calcining the barium-microsphere mixture to form a first calcined material;
• wherein:
• prior to the mixing with the barium solution, the microspheres comprise Y-zeolite crystallized as a layer on the surface of a porous alumina-containing matrix;
• and
• the mixing with the barium solution is conducted at acidic pH conditions.