Insights into structure–performance relationship in the catalytic cracking of high density polyethylene

Dai, Leilei; Zhou, Nan; Cobb, Kirk; Chen, Paul; Ruan, Roger; Liu, Yuhuan; Zou, Rongge; Lei, Hanwu; Mohamed, Badr A.; Cheng, Yanling; Ruan, Roger

doi:10.1016/j.apcatb.2022.121835

Cited by 34 publications

(10 citation statements)

References 41 publications

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Section: The Structure–activity Relationships In Catalytic Cracking O...mentioning

confidence: 99%

“…As shown in Figure a, they observed that the introduction of mesopores in the zeolite greatly enhanced the catalytic activity because the mesopores increased the accessibility of the active sites and shortened the diffusion path. In a recent study, Ruan et al employed the C B factor (BAS surface density) to describe the relationship between BAS concentration and pore structure. , The modified zeolites have a moderate C B value and the relatively highest catalyst activity by two desilication methods to introduce a mesopore structure (H- and T-series) (Figure b). It is worth noting that the introduction of mesopores could be ineffective if the acid sites are severely damaged by an alkali treatment.…”

Section: The Structure–activity Relationships In Catalytic Cracking O...mentioning

confidence: 99%

“…In a recent study, Ruan et al employed the C B factor (BAS surface density) to describe the relationship between BAS concentration and pore structure. 57,136 The modified zeolites have a moderate C B value and the relatively highest catalyst activity by two desilication methods to introduce a mesopore structure (H-and T-series) (Figure 7b). It is worth noting that the introduction of mesopores could be ineffective if the acid sites are severely damaged by an alkali treatment.…”

Section: Effect Of a Mesoporousmentioning

confidence: 99%

“…As a class of crystalline nanoporous materials, zeolites have large specific surface areas, well-defined microporous channels, and adjustable acidities. − Due to their excellent catalytic activities, unique selectivities, and relatively low costs, zeolites have been commercially synthesized and widely applied in various petrochemical industries, especially in catalytic re-forming, aromatization, and cracking of hydrocarbons. − In fact, the catalytic cracking of polyolefins over zeolites has similarities to that of long-chain alkanes, which has inspired many research efforts devoted to the catalytic conversion of polyolefins using zeolites. − Previous studies and reviews have mainly focused on the catalytic activity and product distribution over different zeolite catalysts. An increasing number of current research studies investigated the structure–activity relationships over modified zeolites or composites. , However, there is still a lack of systematic and in-depth discussion.…”

Section: Introductionmentioning

confidence: 99%

“…An increasing number of current research studies investigated the structure− activity relationships over modified zeolites or composites. 57,58 However, there is still a lack of systematic and in-depth discussion.…”

Section: Introductionmentioning

confidence: 99%

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Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Dong

Liu

et al. 2022

ACS Catal.

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Polyolefins, the largest used commodity plastics in the world, find extensive application in many fields. However, most end up in landfills or incineration, leading to severe ecological crises, environmental pollution, and serious resource waste problems. As representatives on chemical upcycling of polyolefin plastics polyolefin waste to fuels and bulk/fine chemicals, polyolefin catalytic cracking and hydrocracking based on zeolite or metal/zeolite composite catalysts are considered the most effective paths due to their large capacity and strong adaptability to existing petrochemical equipment. After an overview of the reaction mechanisms of pyrolysis and catalytic cracking, this review aims to comprehensively discuss the influence of zeolite catalyst structure (acidity, pore structure, and morphology) on the catalytic activity, selectivity, and stability of polyolefin cracking, particularly emphasizing the importance for matching acidity and pore structure for target product formation. Subsequently, the structure–activity relationship between the metal site and zeolite’s acid site in polyolefin hydrocracking is also discussed. In the end, emerging opportunities and challenges are proposed to promote a more efficient way for polyolefin chemical upcycling.

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Section: The Structure–activity Relationships In Catalytic Cracking O...mentioning

confidence: 99%

Section: The Structure–activity Relationships In Catalytic Cracking O...mentioning

confidence: 99%

Section: Effect Of a Mesoporousmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Dong

Liu

et al. 2022

ACS Catal.

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Utilization of Deposited Coke on Zeolites During the Catalytic Cracking of Nitrogen‐Containing Polymer for the Oxygen Reduction Reaction

Kokuryo,

Shu,

Taniguchi

et al. 2023

Advanced Sustainable Systems

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This work focuses on the development of a new method to utilize deposited coke on zeolite catalysts, formed during the plastic waste cracking. Nitrogen‐doped carbon catalysts are prepared using nylon‐66 and Zn2+ ion‐exchanged ZSM‐5 zeolites. After the cracking reaction, nitrogen‐doped carbon materials are obtained by removing zeolites from zeolite/coke composites using base and acid treatment. The synthesized N‐doped carbon using Zn2+ type ZSM‐5 zeolites exhibits higher catalytic performance on the oxygen reduction reaction (ORR) with an onset potential of 0.95 V (vs RHE) and a half‐wave potential of 0.80 V (vs RHE) than that using H+ type ZSM‐5 zeolites. The characterization revealed that the evaporation of Zn2+ in zeolites significantly enhanced the porosity of N‐doped carbon. Moreover, the aromatization and poly‐cyclization reactions promoted the generation of highly active edge Valley‐N sites, leading to their outstanding activity on ORR. This work provides new directions for the utilization of deposited coke on zeolites.

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Micelles Cascade Assembly to Tandem Porous Catalyst for Waste Plastics Upcycling

Feng,

Duan,

Hung

et al. 2024

Angewandte Chemie

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Catalytic upcycling of polyolefins into high‐value chemicals represents the direction in end‐of‐life plastics valorization, but poses great challenges. Here, we report the synthesis of a tandem porous catalyst via a micelle cascade assembly strategy for selectively catalytic cracking of polyethylene into olefins at a low temperature. A hierarchically porous silica layer from mesopore to macropore is constructed on the surface of microporous ZSM‐5 nanosheets through cascade assembly of dynamic micelles. The outer macropore arrays can adsorb bulky polyolefins quickly by the capillary and hydrophobic effects, enhancing the diffusion and access to active sites. The middle mesopores present a nanoconfinement space, pre‐cracking polyolefins into intermediates by weak acid sites, which then transport into zeolites micropores for further cracking by strong Brønsted acid sites. The hierarchically porous and acidic structures, mimicking biomimetic protease catalytic clefts, ideally match the tandem cracking steps of polyolefins, thus suppressing coke formation and facilitating product escape. As a result, light hydrocarbons (C1‐C7) are produced with a yield of 443 mmol·gZSM‐5‐1, where 74.3% of them are C3‐C6 olefins, much superior to ZSM‐5 and porous silica catalysts. This tandem porous catalyst exemplifies a superstructure design of catalytic cracking catalysts for industrial and economical upcycling of plastic wastes.

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Insights into structure–performance relationship in the catalytic cracking of high density polyethylene

Cited by 34 publications

References 41 publications

Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Utilization of Deposited Coke on Zeolites During the Catalytic Cracking of Nitrogen‐Containing Polymer for the Oxygen Reduction Reaction

Micelles Cascade Assembly to Tandem Porous Catalyst for Waste Plastics Upcycling

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