Organic-Free Synthesis of High-Silica Zeolite Y with Aluminophosphate as the Aluminum Carrier

Abstract

The wide application of zeolite Y in petrochemical industry is well-known as one of the milestones in zeolite chemistry and heterogeneous catalysis. However, the traditional organic-free synthesis typically produces (hydro)thermally unstable zeolite Y with Si/Al atomic ratio (SAR) less than 2.5. Inspired by drug delivery process in which active components are kinetically controlled released, we develop a unique approach based on the pre-synthesized aluminum carrier to prepare one of the most siliceous zeolite Y with SAR up to 3.44 without using organics. The crystalline or amorphous aluminophosphates serve as the ideal carrier for the controlled incorporation of Al into zeolite framework during zeolite Y crystallization. Experimental and theoretical results reveal that the partial introduction of aluminophosphate as Al source would rationally regulate the crystallization kinetics, facilitating the formation of high-silica zeolite Y with random Al distribution. This approach enhances the hydrothermal stability and catalytic performance of zeolite Y in benchmark reaction.