Catalytic Upcycling of Polyolefins

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(16), P. 9457 - 9579

Published: Aug. 16, 2024

The large production volumes of commodity polyolefins (specifically, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride)), in conjunction with their low unit values multitude short-term uses, have resulted a significant pressing waste management challenge. Only small fraction these is currently mechanically recycled, the rest being incinerated, accumulating landfills, or leaking into natural environment. Since are energy-rich materials, there considerable interest recouping some chemical value while simultaneously motivating more responsible end-of-life management. An emerging strategy catalytic depolymerization, which portion C-C bonds polyolefin backbone broken assistance catalyst and, cases, additional molecule reagents. When products molecules materials higher own right, as feedstocks, process called upcycling. This review summarizes recent progress for four major upcycling strategies: hydrogenolysis, (hydro)cracking, tandem processes involving metathesis, selective oxidation. Key considerations include macromolecular reaction mechanisms relative to mechanisms, design transformations, effect conditions on product selectivity. Metrics describing critically evaluated, an outlook future advances described.

Language: Английский

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Review on Catalytic Depolymerization of Polyolefin Waste by Hydrogenolysis: State-of-the-Art and Outlook

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(3), P. 1676 - 1691

Published: Jan. 22, 2024

Mechanical recycling of plastic waste is not sustainable and inefficient in terms the resources needed to accomplish process, quality materials obtained from this technique substandard. Chemical polymers appears be preferable because technology allows for production new materials. This review compiles most recent research which selected transition metals are used as catalysts hydrogenolytic depolymerization polyolefins a polymer upcycling process. Hydrogenolysis an emerging chemical method that uses transition-metal complexes presence hydrogen cleave C–C bonds substances into shorter hydrocarbons. Transition such Ruthenium (Ru), Platinum (Pt), Nickel (Ni), Cobalt (Co), Zirconium (Zr), Tantalum (Ta), Rhodium (Rh) have been utilized recently type reaction. hydrogenolysis can produce valuable hydrocarbon products, gas/liquid fuels lubricating oils, under relatively milder operational conditions with less environmental impact. The focused on supported metal organometal catalytic system their mechanism polyolefin pathways detailed investigation impact reaction parameters high gasoline, diesel, light lubricants.

Language: Английский

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Upcycling Waste Plastics with a C–C Backbone by Heterogeneous Catalysis

Langmuir, Journal Year: 2024, Volume and Issue: 40(10), P. 5077 - 5089

Published: Feb. 15, 2024

Plastics with an inert carbon–carbon (C–C) backbone, such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC), are the most widely used types of plastic in human activities. However, many these polymers were directly discarded nature after use, few appropriately recycled. This not only threatens natural environment but also leads to waste carbon resources. Conventional chemical recycling plastics, including pyrolysis catalytic cracking, requires a high energy input due inertness C–C bonds C–H complex product distribution. In recent years, significant progress has been made development catalysts introduction small molecules additional coreactants, which could potentially overcome challenges. this Review, we summarize highlight strategies that address issues upcycling backbone plastics molecules, particularly heterogeneous catalysis. We believe review will inspire methods for using

Language: Английский

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Poisoning effect of polyvinyl chloride on the catalytic pyrolysis of mixed plastics over zeolites

Science China Chemistry, Journal Year: 2024, Volume and Issue: 67(7), P. 2265 - 2273

Published: June 4, 2024

Language: Английский

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Chemical Upcycling of Polyolefin Plastics Using Structurally Well-defined Catalysts

JACS Au, Journal Year: 2024, Volume and Issue: 4(6), P. 2081 - 2098

Published: June 4, 2024

Single-use polyolefins are widely used in our daily life and industrial production due to their light weight, low cost, superior stability, durability. However, the rapid accumulation of plastic waste low-profit recycling methods resulted a global crisis. Catalytic hydrogenolysis is regarded as promising technique, which can effectively selectively convert polyolefin value-added products. In this perspective, we focus on design synthesis structurally well-defined catalysts across mesoscopic, nanoscopic, atomic scales, accompanied by insights into future directions catalyst for further enhancing catalytic performance. These principles also be applied depolymerization other polymers ultimately realize chemical upcycling plastics.

Language: Английский

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Selectivity control by zeolites during methanol-mediated CO₂ hydrogenation processes

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

The thermocatalytic conversion of CO2 with green or blue hydrogen into valuable energy and commodity chemicals such as alcohols, olefins, aromatics emerges one the most promising strategies for mitigating global warming concerns in future. This process can follow either a CO2-modified Fischer-Tropsch synthesis route methanol-mediated route, latter being favored its high product selectivity beyond Anderson-Schulz-Flory distribution. Despite progress CO2-led over bifunctional metal/zeolite catalysts, challenges persist developing catalysts both activity due to complexity hydrogenation reaction networks difficulty controlling C-O bond activation C-C coupling on multiple active sites within zeolites. Moreover, different construction proximity modes bifunctionality involving redox-based metallic acidic zeolite have been explored, which not systematically reviewed derive reliable structure-reactivity relationships. To bridge this "knowledge gap", review, we will provide comprehensive critical overview contemporary research zeolite-confined metal alcohol zeolite-based tandem/cascade catalytic systems C2+ hydrocarbons via route. Accordingly, special emphasis be placed evaluating how confinement effects "redox-acid" influence outcomes, particularly regarding selectivity, has also analyzed from mechanistic standpoint. review examine synergistic interactions among various catalyst components that govern catalysis, offering insights rational design new improved systems. By discussing current recognizing future opportunities using aims contribute advancement sustainable efficient processes valorization.

Language: Английский

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Effective Methane Suppression in Upcycling of Polyethylene into Fuels via Alloying Platinum with Ruthenium Supported on ZSM-5 Zeolite

Nano Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 13, 2025

Ruthenium (Ru)-based catalysts are active in catalyzing polyethylene (PE) upcycling, but their tendency for methanation devalues the process. Although previous works confirmed that regulation of Ru structure can inhibit methane yields, mechanism is still unclear, and catalytic performance remains higher upside potential. Herein, we synthesized M-Ru/H-ZSM-5 (M = Pt, Pd, Rh) PE upcycling. Pt-Ru/H-ZSM-5 had better conversion (84.36%) liquid fuel selectivity (78.38%) extremely low (8.43%), which be ascribed to its more electron-deficient Ruδ+ species synergistic effect induced by Pt doping. Through density functional theory calculations, nature inhibition was uncovered reaction pathway proposed. Furthermore, catalyst demonstrated stability reusability, as well efficacy upcycling various PEs. This work reveals Ru-based reactions, promoting plastic recycling development.

Language: Английский

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Recent advances in polyolefin plastic waste upcycling via mild heterogeneous catalysis route from catalyst development to process design

Cell Reports Physical Science, Journal Year: 2024, Volume and Issue: 5(7), P. 102075 - 102075

Published: July 1, 2024

Plastics, integral to modern life since their inception, pervade our daily existence. However, conventional approaches managing plastic waste, especially polyolefin pose significant challenges resources and the environment. Recent years have witnessed remarkable advancements in realm of waste management through traditional heterogeneous catalysis pathways, notably under mild conditions such as hydrocracking, hydrogenolysis, metathesis. In this comprehensive review, we offer a systematic overview spanning catalyst development process design engineering. We intricately compare various reaction routes, elucidate mechanisms, rigorously evaluate processes. Additionally, present insights into future directions for both academic research industrial recycling via routes at conditions.

Language: Английский

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Consumer Grade Polyethylene Recycling via Hydrogenolysis on Ultrafine Supported Ruthenium Nanoparticles

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(11)

Published: Dec. 18, 2023

Catalytic hydrogenolysis has the potential to convert high-density polyethylene (HDPE), which comprises about 30 % of plastic waste, into valuable alkanes. Most investigations have focused on increasing activity for lab grade HDPEs displaying low molecular weight, with limited mechanistic understanding product distribution. No efficient catalyst is available consumer grades due their lower reactivity. This study targets HDPE used in bottle caps, a waste form generated globally at rate approximately one million units per hour. Ultrafine ruthenium particles (1 nm) supported titania (anatase) achieved up 80 conversion light alkanes (C

Language: Английский

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Increase in the effective viscosity of polyethylene under extreme nanoconfinement

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(2)

Published: Jan. 12, 2024

Understanding polymer transport in nanopores is crucial for optimizing heterogeneously catalyzed processes upcycling and fabricating high-performance nanocomposite films membranes. Although confined dynamics have been extensively studied, the behavior of polyethylene (PE)—the most widely used commodity polymer—in pores smaller than 20 nm remains largely unexplored. We investigate effects extreme nanoconfinement on PE using capillary rise infiltration silica nanoparticle packings with average pore radii ranging from ∼1 to ∼9 nm. Using situ ellipsometry Lucas–Washburn model, we discover a previously unknown inverse relationship between effective viscosity (ηeff) radius (Rpore). Additonally, determine that under these conditions primarily governed by physical confinement, rather surface chemistry. refine an existing theory provide generalized formalism describe over wide range (from 1 larger). Our results offer valuable insights catalyst supports improving fabrication.

Language: Английский

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