Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking

Nakai, Ryuga; Kokuryo, Shinya; Miyake, Koji; Murata, Yoshiki; Uchida, Yoshiaki; Mizusawa, Atsushi; Kubo, Tadashi; Nishiyama, Norikazu

doi:https://doi.org/10.1002/cmtd.202500157

Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking

Nakai, Ryuga; Kokuryo, Shinya; Miyake, Koji et al.

Chemistry–Methods, 2026, 6(1), e202500157

Number of Access:18（2026-02-18 09:16 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/103711

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Title	Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking
Creator	CreatorName Nakai, Ryuga
	CreatorName Kokuryo, Shinya
	NRID 1000040844717 1000040844717 ORCID 0000-0001-9868-5391 0000-0001-9868-5391 researchmap permalink 7000028816 7000028816 Scopus Author ID 56594314800 56594314800 CreatorName Miyake, Koji
	CreatorName Murata, Yoshiki
	NRID 1000060559558 1000060559558 ORCID 0000-0001-5043-9239 0000-0001-5043-9239 researchmap permalink Yoshiaki_Uchida Yoshiaki_Uchida Scopus Author ID 8348749200 8348749200 CreatorName Uchida, Yoshiaki
	CreatorName Mizusawa, Atsushi
	CreatorName Kubo, Tadashi
	NRID 1000010283730 1000010283730 researchmap permalink read0046501 read0046501 Scopus Author ID 7201750198 7201750198 CreatorName Nishiyama, Norikazu
Description	Nakai Ryuga, Kokuryo Shinya, Miyake Koji, et al. Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking. Chemistry–Methods 6, e202500157 (2026); https://doi.org/10.1002/cmtd.202500157.
Abstract	Zeolites are widely studied as promising catalysts for the chemical recycling of plastics due to their inherent microporosity and shape-selective properties. The accessibility of polymer chains to internal acid sites is limited, and initial reactions are supposed to occur near the external surface. A deeper understanding of the role of external acid sites is required to optimize the structure and morphology of the zeolites. In this study, a novel ZSM-5 zeolite catalyst with Brønsted acid sites selectively localized only on the external surface (ZSM-5-SA) is synthesized via selective ion exchange using bulky tetrapropylammonium ions, followed by calcination. Catalytic testing of low- and high-density polyethylene revealed that the initial degradation is mainly triggered at Brønsted acid sites located on the external surface and near-surface internal regions. Once protonated, the polymer chains undergo β-scission, leading to similar product distributions regardless of the acid site density. These findings highlight that a small number of spatially accessible acid sites can effectively initiate and propagate the cracking reaction. These findings establish a direct link between the acid site location and reaction pathway and offer a rational design principle for advanced zeolite catalysts tailored for polymer cracking and chemical upcycling.
Publisher	Wiley
Source Title	Chemistry–Methods
Volume (Issue)	6(1)
Page	e202500157
Date of Issued	2026-01-27
Language	English
Handle URL	https://hdl.handle.net/11094/103711
PISSN	26289725
eISSN	26289725
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1002/cmtd.202500157
Access Rights	open access
CopyRight	This article is licensed under a Creative Commons Attribution 4.0 International License.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCMI Type	Text
DCTERMS.bibliographicCitation	Chemistry–Methods. 2026, 6(1), p. e202500157
DC.title	Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking
DC.creator	Nakai, Ryuga
	Kokuryo, Shinya
	Miyake, Koji
	Murata, Yoshiki
	Uchida, Yoshiaki
	Mizusawa, Atsushi
	Kubo, Tadashi
	Nishiyama, Norikazu
DC.publisher	Wiley
DC.language' scheme='DCTERMS.RFC1766	English
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2026-01-27
DC.identifier	https://doi.org/10.1002/cmtd.202500157
DC.description	Nakai Ryuga, Kokuryo Shinya, Miyake Koji, et al. Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking. Chemistry–Methods 6, e202500157 (2026); https://doi.org/10.1002/cmtd.202500157.
DCTERMS.abstract	Zeolites are widely studied as promising catalysts for the chemical recycling of plastics due to their inherent microporosity and shape-selective properties. The accessibility of polymer chains to internal acid sites is limited, and initial reactions are supposed to occur near the external surface. A deeper understanding of the role of external acid sites is required to optimize the structure and morphology of the zeolites. In this study, a novel ZSM-5 zeolite catalyst with Brønsted acid sites selectively localized only on the external surface (ZSM-5-SA) is synthesized via selective ion exchange using bulky tetrapropylammonium ions, followed by calcination. Catalytic testing of low- and high-density polyethylene revealed that the initial degradation is mainly triggered at Brønsted acid sites located on the external surface and near-surface internal regions. Once protonated, the polymer chains undergo β-scission, leading to similar product distributions regardless of the acid site density. These findings highlight that a small number of spatially accessible acid sites can effectively initiate and propagate the cracking reaction. These findings establish a direct link between the acid site location and reaction pathway and offer a rational design principle for advanced zeolite catalysts tailored for polymer cracking and chemical upcycling.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	103711
citation_title	Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking
citation_author	Nakai, Ryuga
	Kokuryo, Shinya
	Miyake, Koji
	Murata, Yoshiki
	Uchida, Yoshiaki
	Mizusawa, Atsushi
	Kubo, Tadashi
	Nishiyama, Norikazu
citation_publisher	Wiley
citation_language	English
citation_date	2026-01-27
citation_journal_title	Chemistry–Methods
citation_volume	6
citation_issue	1
citation_firstpage	e202500157
citation_doi	https://doi.org/10.1002/cmtd.202500157
citation_public_url	https://hdl.handle.net/11094/103711

Selective H⁺ Exchange for External Surface of Zeolites to Elucidate the Role of External Acid Sites of Zeolite in Polyolefin Cracking

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