Iron-Containing TS‑1 Zeolites with Controllable Mesopores by Desilication and Their Application in Phenol Hydroxylation

Hierarchical iron-containing TS-1 zeolites (FTS) were successfully synthesized via post-treatment desilication over microporous Fe-TS-1, which were prepared through a one-step hydrothermal synthesis. The prepared samples were characterized by X-ray diffraction, N₂ adsorption–desorption, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, and X-ray fluorescence spectrometry. The experimental results illustrated that the MFI structure of all the FTS samples remained unchanged after NaOH desilication and acid treatment. The newly created mesopores can be controlled by changing the amount of framework Fe, as the extraction of Si could be affected because of the inhibitory effect of iron species during the desilication process. The catalytic performance of the prepared samples in phenol hydroxylation with H₂O₂ was investigated. Among all the samples, FTS-50-D showed a highest phenol conversion of 45.2% and a dihydroxybenzene selectivity of 95.2%. Besides, FTS-50-D also showed good reusability for five recycling tests.