Method for synthesizing mesoporous nano-sized ultra-stable Y zeolite

A method for synthesizing a mesoporous nano-sized ultra-stable Y zeolite, the method comprising:

• preparing a 0.1 to 2.0 M ammonium hexafluorosilicate solution;
• preparing a 0.1 to 2.0 M ammonium hydroxide solution;
• combining a microporous nano-sized Y zeolite having a SiO2/Al2O3 molar ratio of less than 5.2 with 30 to 1,000 milliliters water per gram of the microporous Y zeolite on a dry basis 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;
• adding the ammonium hexafluorosilicate solution and the ammonium hydroxide solution in a drop-wise manner to the heated microporous Y zeolite slurry to form a treated zeolite solution;
• holding the treated zeolite solution at 50° C. to 100° C. with stirring for a period of 1 to 24 hours;
• filtering and washing the treated zeolite solution with water to form an ultra-stable Y zeolite precursor;
• drying the ultra-stable Y zeolite precursor at 80° C. to 150° C. for 6 to 24 hours to form a dried zeolite precursor;
• and
• calcining the dried zeolite precursor at 250° C. to 600° C. for 1 to 8 hours to form the mesoporous nano-sized ultra-stable Y zeolite.