Visualizing Dealumination of a Single Zeolite Domain in a Real‐Life Catalytic Cracking Particle

摘要

Fluid catalytic cracking (FCC) catalysts play a central role in the chemical conversion of crude oil fractions. Using scanning transmission X‐ray microscopy (STXM) we investigate the chemistry of one fresh and two industrially deactivated (ECAT) FCC catalysts at the single zeolite domain level. Spectro‐microscopic data at the Fe L3, La M5, and Al K X‐ray absorption edges reveal differing levels of deposited Fe on the ECAT catalysts corresponding with an overall loss in tetrahedral Al within the zeolite domains. Using La as a localization marker, we have developed a novel methodology to map the changing Al distribution of single zeolite domains within real‐life FCC catalysts. It was found that significant changes in the zeolite domain size distributions as well as the loss of Al from the zeolite framework occur. Furthermore, inter‐ and intraparticle heterogeneities in the dealumination process were observed, revealing the complex interplay between metal‐mediated pore accessibility loss and zeolite dealumination.