Postsynthesis of mesoporous ZSM-5 zeolites with TPAOH-assisted desilication and determination of activity performance in N₂O decomposition

Taking tetrapropylammonium hydroxide as a protector for the zeolite crystal during desilication, a series of alkaline-treated zeolite supports with different TPA⁺/OH⁻ molar ratios were obtained and applied in N₂O catalytic decomposition after iron modification. The experimental result shows that catalytic performance could be enhanced with a suitable TPA⁺/OH⁻ ratio, which is even better than that treated in pure NaOH alkaline solution. Among these samples, Fe–Z5–30–TPA_0.4 exhibits the best catalytic performance and 100% N₂O conversion is achieved at 500 °C. The characterization result shows that the crystalline structure becomes more uniform in the Fe–Z5–30–TPA_0.4 sample. In addition, not only the hierarchical structure is constructed but also the tetrahedrally coordinated aluminum as potential exchange sites are well preserved. This makes the Fe loading increased maximally, which explains the excellent activity of Fe–Z5–30–TPA_0.4 sample.