Methods for synthesizing a mesoporous nano-sized ultra-stable Y zeolite include combining a microporous Y zeolite having a SiO2/Al2O3 molar ratio of less than 5.2 with water to form a microporous Y zeolite slurry and heating the microporous Y zeolite slurry to 30° C. to 100° C. to form a heated microporous Y zeolite slurry. Further the method includes adding a 0.1M to 2.0M ammonium hexafluorosilicate solution and a 0.1M to 2.0M ammonium hydroxide solution in a drop-wise manner, either sequentially or simultaneously, to the heated microporous Y zeolite slurry to form a treated zeolite solution and holding the treated zeolite solution at 50° C. to 100° C. Finally the method includes filtering and washing the dealuminated solution with water to form an ultra-stable Y zeolite precursor, drying the ultra-stable Y zeolite precursor, and calcining the dried zeolite precursor to form the nano-sized ultra-stable Y zeolite.