Understanding the high hydrothermal stability and NH3-SCR activity of the fast-synthesized ERI zeolite

Zhu, Jin; Liu, Zhendong; Xu, Le; Ohnishi, Takeshi; Yanaba, Yutaka; Ogura, Masaru; Wakihara, Toru; Okubo, Tatsuya

doi:10.1016/j.jcat.2020.08.033

Cited by 38 publications

(27 citation statements)

References 63 publications

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“…Hence, the inorganic cations and protons could be transported via gme cages and empty aft cages. In contrast, the irremovable cations in ERI and RHO should be trapped in the closed cages of their structures ( can cages in the ERI structure and d 8 r in the RHO structure) that are not connected to other cages via eight or larger rings ( 59 , 60 ). The 13% of sodium cations remaining after the acid treatment of AFX zeolite may have been stuck in aft cages that are co-occupied by OSDA cations.…”

Section: Discussionmentioning

confidence: 99%

Dealumination of small-pore zeolites through pore-opening migration process with the aid of pore-filler stabilization

et al. 2022

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Small-pore zeolites are gaining increasing attention owing to their superior catalytic performance. Despite being critical for the catalytic activity and lifetime, postsynthetic tuning of bulk Si/Al ratios of small-pore zeolites has not been achieved with well-preserved crystallinity because of the limited mass transfer of aluminum species through narrow micropores. Here, we demonstrate a postsynthetic approach to tune the composition of small-pore zeolites using a previously unexplored strategy named pore-opening migration process (POMP). Acid treatment assisted by stabilization of the zeolite framework by organic cations in pores is proven to be successful for the removal of Al species from zeolite via POMP. Furthermore, the dealuminated AFX zeolite is treated via defect healing, which yields superior hydrothermal stability against severe steam conditions. Our findings could facilitate industrial applications of small-pore zeolites via aluminum content control and defect healing and could elucidate the structural reconstruction and arrangement processes for inorganic microporous materials.

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Section: Discussionmentioning

confidence: 99%

Dealumination of small-pore zeolites through pore-opening migration process with the aid of pore-filler stabilization

et al. 2022

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“…In addition to the CHA zeolite, many other types of zeolites, such as 8‐MR zeolites LTA, [ 16b,202 ] ERI, [ 203 ] AFX, [ 204 ] AEI, [ 205 ] KFI, [ 206 ] UFI, [ 202a ] RHO, [ 207 ] and RTH, [ 208 ] 10‐MR zeolites MFI, [ 209 ] SFW, [ 210 ] and FER, [ 211 ] and 12‐MRs zeolite MOR, [ 212 ] MSE, [ 213 ] and *BEA, [ 214 ] were also used as effective supports to anchor the Cu species for the NH 3 ‐SCR reaction. The hydrothermal stability and SO 2 resistance of Cu‐containing zeolites were key factors to meet the practical requirements in NH 3 ‐SCR reactions and numerous studies have been focused on these topics in the recent decade.…”

Section: Other Reactionsmentioning

confidence: 99%

Advances in Catalytic Applications of Zeolite‐Supported Metal Catalysts

2021

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“…Nitrogen oxides (NO x ) emitted from high-temperature combustion processes in diesel engines, power stations and industrial heaters are important atmospheric pollutants, which can lead to several environmental problems, for example, acid rain, ozone depletion, photochemical smog and greenhouse effects (Du et al 2020;Zhu et al 2020;Kim et al 2020). Over the past few decades, selective catalytic reduction (SCR) with NH 3 has become the most effective technology for abating NO x emissions from mobile and stationary sources (Gong et al 2020;Ma et al 2020).…”

Section: Introductionmentioning

confidence: 99%

An investigation on the promoting effect of Pr modification on SO2 resistance over MnOx catalysts for selective reduction of NO with NH3

Zhai

Han

et al. 2021

Environ Sci Pollut Res

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Manganese oxides (MnO x ) exhibit excellent low-temperature activities in SCR reaction of NO with NH 3 , and they are considered as a promising catalyst for future application. However, MnO x still suffer from poor resistance to SO 2 and H 2 O. In this work, Pr was used to modify MnO x catalysts via co-precipitation process, and MnPrO x catalyst exhibited superior SO 2 resistance over pure MnO x catalyst. A series of characterization techniques, such as XRD, BET, H 2 -TPR, XPS, TG and in-situ DRIFTS, were adopted to explore the promoting effect of Pr modi cation on SO 2 resistance over MnO x catalyst in detail. The results indicated that, in the presence of SO 2 in feed gas, it seemed that PrO x rather than MnO x were apt to react with SO 2 , which was favorable to protect Mn active sites on the catalyst surface to some extent. It was known that there was strong competitive adsorption between SO 2 and NH 3 /NO species on SCR catalyst surface. In-situ DRIFTS results revealed that the adsorption of NH 3 and NO on MnO x catalyst had been severely suppressed after the introduction of SO 2 , resulting in the relevant SCR reactions following either L-H or E-R mechanisms would be inhibited obviously. But for Pr-modi ed MnO x catalyst, the introduction of SO 2 almost had no effect on the adsorption of NH 3 on catalyst surface, while it exerted a relatively noticeable impact on the adsorption of NO. As a result, SCR reactions occurred on Pr-modi ed MnO x catalyst surface could still proceed in a near-normal way through E-R rather than L-H mechanisms.Therefore, Pr modi cation on MnO x catalyst exhibited a distinctively promoting effect on SO 2 resistance performance in SCR process. HighlightsPr-modi ed MnO x catalyst exhibited superior SO 2 resistance over MnO x catalyst.Pr modi cation could inhibit the sulfation of Mn active sites on the surface of MnO x catalyst.For Pr-modi ed MnO x catalyst, the adsorption of NH 3 on Lewis acid sites was almost not affected by SO 2 , and the inhibition degree of SO 2 for NO adsorption was lower than that of MnO x catalyst.The SCR reaction on Pr-modi ed MnO x catalyst might follow E-R mechanism in the presence of SO 2 .

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Understanding the high hydrothermal stability and NH3-SCR activity of the fast-synthesized ERI zeolite

Cited by 38 publications

References 63 publications

Dealumination of small-pore zeolites through pore-opening migration process with the aid of pore-filler stabilization

Dealumination of small-pore zeolites through pore-opening migration process with the aid of pore-filler stabilization

Advances in Catalytic Applications of Zeolite‐Supported Metal Catalysts

An investigation on the promoting effect of Pr modification on SO2 resistance over MnOx catalysts for selective reduction of NO with NH3

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