Formation of USY at lower steam temperature by embedding of Ga3+ into framework of NaY and its catalytic cracking performance

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• Zeolite [Ga,Al]-Y with high content of 24.4 wt% Ga 2 O 3 can be synthesized by hydrothermal method. • [Ga,Al]-Y can be operated at lower steam temperature to form [Ga,Al]-USY due to distorted structure. • [Ga,Al]-USY prepared at lower steam temperature has good catalytic performance for cracking of 1,3,5-TIPB and n -octane. Decreasing steam treating temperature of zeolite Y to prepare USY has great attraction for industrial production of FCC catalysts, which is often operated at high temperature thus leading to huge energy consumption. Heteroatoms in the framework of zeolite Y are easier to be removed under steam condition, but the introduction of heteroatoms often leads to the decrease of relative crystallinity of zeolite. When Ga 3+ is introduced into the framework of zeolite Y, high crystallinity is well maintained in this work. Interestingly [Al, Ga]-NaY can be treated at low steam temperature to form [Al, Ga]-USY with very good mesoporosity and high framework SiO 2 /Al 2 O 3 ratio. The sample [Al, Ga]-NaY-8 has a distinctive micropore size distribution at 0.92 nm which is much bigger than conventional microporous NaY. DFT study disclosed the reason of low temperature steam treatment. The catalytic cracking of 1,3,5-TIPB and n -octane showed that the catalyst [Al, Ga]-USY obtained at lower steam treating temperature presented good performance.