Insights into in-situ catalytic degradation of plastic wastes over zeolite-based catalyst from perspective of three-dimensional pore structure evolution

Xu, Didi; Lu, Xuekun; Zhang, Ye Shui; Shearing, Paul R.; Zhang, Shuping; Brett, Dan J. L.; Wang, Shurong

doi:10.1016/j.cej.2022.138402

Cited by 6 publications

(1 citation statement)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Zeolites are essential materials in many processes that are crucial to the current needs of our society. Some of the most recent examples are conversion of biomass to olefins, plastic waste degradation, NH 3 –SCR for NO x abatement, and a variety of adsorption and separation processes . Their widespread use has resulted not only in the preparation of many new materials with different topology types but also in the gradual optimization of the properties of zeolites of a given framework type via different syntheses and post-synthetic treatments.…”

Section: Introductionmentioning

confidence: 99%

Synthetic Control of the Defect Structure and Hierarchical Extra-Large-/Small-Pore Microporosity in Aluminosilicate Zeolite SWY

Chitac,

Zholobenko,

Fletcher

et al. 2023

J. Am. Chem. Soc.

View full text Add to dashboard Cite

The SWY-type aluminosilicate zeolite, STA-30, has been synthesized via different routes to understand its defect chemistry and solid acidity. The synthetic parameters varied were the gel aging, the Al source, and the organic structure directing agent. All syntheses give crystalline materials with similar Si/Al ratios (6–7) that are stable in the activated K,H-form and closely similar by powder X-ray diffraction. However, they exhibit major differences in the crystal morphology and in their intracrystalline porosity and silanol concentrations. The diDABCO-C82+ (1,1′-(octane-1,8-diyl)bis(1,4-diazabicyclo[2.2.2]octan)-1-ium)-templated STA-30 samples (but not those templated by bisquinuclidinium octane, diQuin-C82+) possess hierarchical microporosity, consisting of noncrystallographic extra-large micropores (13 Å) that connect with the characteristic swy and gme cages of the SWY structure. This results in pore volumes up to 30% greater than those measured in activated diQuin-C8_STA-30 as well as higher concentrations of silanols and fewer Brønsted acid sites (BASs). The hierarchical porosity is demonstrated by isopentane adsorption and the FTIR of adsorbed pyridine, which shows that up to 77% of the BASs are accessible (remarkable for a zeolite that has a small-pore crystal structure). A structural model of single can/d6r column vacancies is proposed for the extra-large micropores, which is revealed unambiguously by high-resolution scanning transmission electron microscopy. STA-30 can therefore be prepared as a hierarchically porous zeolite via direct synthesis. The additional noncrystallographic porosity and, subsequently, the amount of SiOHs in the zeolites can be enhanced or strongly reduced by the choice of crystallization conditions.

show abstract

Section: Introductionmentioning

confidence: 99%