Solar-driven photocatalysis for recycling and upcycling plastics

Applied Catalysis B Environment and Energy, Journal Year: 2023, Volume and Issue: 341, P. 123357 - 123357

Published: Sept. 30, 2023

Language: Английский

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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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Photothermocatalytic Wet Reforming of Waste Plastics to Syngas

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

The increasing accumulation of plastic waste in the environment poses a serious threat to ecosystem and health sector, urging us develop sustainable strategies tackle this issue. Converting into platform chemicals using energy primary resources can mitigate environmental pollution reduce CO2 emissions. In study, polyolefins were transformed syngas through wet reforming process over nickel-supported oxygen vacancy-rich titanium dioxide (Ni/TiO2-x) catalyst with water as reactant under light irradiation. focused irradiation readily increase temperature reactor for dehydrogenation degradation polyethylene (PE) occur, followed by PE-derived compounds gaseous hydrocarbons syngas. Additionally, transfer electrons from TiO2-x nickel components facilitates aforementioned reactions. current work presents strategy valorization syngas, serving feedstock subsequent production various chemicals.

Language: Английский

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Highly Selective and Efficient Perdeuteration of n‐Pentane via H/D Exchange Catalyzed by a Silica‐Supported Hafnium‐Iridium Bimetallic Complex

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(16)

Published: Feb. 19, 2024

A Surface OrganoMetallic Chemistry (SOMC) approach is used to prepare a novel hafnium-iridium catalyst immobilized on silica, HfIr/SiO

Language: Английский

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Alkene Isomerization Using a Heterogeneous Nickel-Hydride Catalyst

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(22), P. 15596 - 15608

Published: May 21, 2024

Transition metal-catalyzed alkene isomerization is an enabling technology used to install distal its original site. Due their well-defined structure, homogeneous catalysts can be fine-tuned optimize reactivity, stereoselectivity, and positional selectivity, but they often suffer from instability nonrecyclability. Heterogeneous are generally highly robust continue lack active-site specificity challenging rationally improve through structural modification. Known single-site heterogeneous for utilize precious metals bespoke, expensive, synthetically intense supports. Additionally, have mediocre inspiring us develop a catalyst with active site made readily available compounds of Earth-abundant elements. Previous work demonstrated that very formed upon protonation Ni[P(OEt)3]4 by H2SO4, generating [Ni–H]+ This incredibly active, also decomposes readily, which severely limits utility. Herein we show using solid acid (sulfated zirconia, SZO300), not only this decomposition prevented, high activity maintained, improved selectivity achieved, broader scope functional groups tolerated. Preliminary mechanistic experiments suggest the catalytic reaction likely goes intermolecular, two-electron pathway. A detailed kinetic study comparing state-of-the-art Ni Pd reveals highest seen Ni/SZO300 system. The reactivity Ni/SZO300, limited isomerization; it competent hydroalkenylation, hydroboration, hydrosilylation, demonstrating broad application catalyst.

Language: Английский

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Polypropylene Degradation Catalyzed by Tantalum Hydrides Supported on Sulfated Alumina

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(16), P. 10765 - 10769

Published: Aug. 1, 2023

Ta–H+ sites supported on sulfated aluminum oxide (SAO), [Ta(H)2(O−)2][SAO] (1), catalyze the hydrogenolysis of isotactic polypropylene (iPP, Mn = 13.3 kDa; Đ 2.4; mmmm 94%) to form low-molecular-weight branched alkanes (C11–C30) in good yields (70%). The formed lose stereochemical information originating from iPP, but residual iPP remains highly isotactic. In presence D2, similar mixtures are containing −CH3–xDx, −CHD, and −CD–. Residual maintains high tacticity incorporates deuterium primarily into −CH3 groups polymer (−CH3–xDx/–CHD–/–CD– ∼10:1:0). 1 reacts with pinacolborane [TaH(κ2-H2BPin)(O−)2][SAO] (2). At 200 °C an melt, 2 products indicative C–H bond activation at internal −CH2– a ∼1:3 ratio, indicating slight kinetic preference for groups. is more reactive toward than high-density polyethylene reactions

Language: Английский

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Treasuring trash: Pt/SrTiO3 catalysts process plastic waste into high-value materials

Matter, Journal Year: 2023, Volume and Issue: 6(10), P. 3296 - 3321

Published: Aug. 8, 2023

Language: Английский

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Effects of surface acidity on the structure of organometallics supported on oxide surfaces

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(28), P. 4115 - 4127

Published: Jan. 1, 2023

Well-defined organometallic cations supported on high surface area oxides are promising heterogeneous catalysts.

Language: Английский

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Mild Catalytic Degradation of Crystalline Polyethylene Units in a Solid State Assisted by Carboxylic Acid Groups

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(28), P. 19599 - 19608

Published: July 2, 2024

Crystalline polyethylenes bearing carboxylic acid groups in the main chain were successfully degraded with a Ce catalyst and visible light. The reaction proceeds crystalline solid state without swelling acetonitrile or water at temperature as low 60 80 °C, employing dioxygen air only stoichiometric reactant nearly quantitative recovery of carbon atoms. Heterogeneous features allowed us to reveal dynamic morphological change polymer crystals during degradation.

Language: Английский

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Active species in chloroaluminate ionic liquids catalyzing low-temperature polyolefin deconstruction

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: July 10, 2024

Abstract Chloroaluminate ionic liquids selectively transform (waste) polyolefins into gasoline-range alkanes through tandem cracking-alkylation at temperatures below 100 °C. Further improvement of this process necessitates a deep understanding the nature catalytically active species and correlated performance in catalyzing critical reactions for polyolefin deconstruction with isoalkanes low temperatures. Here, we address requirement by determining nuclearity chloroaluminate ions their interactions reaction intermediates, combining situ 27 Al magic-angle spinning nuclear magnetic resonance spectroscopy, Raman K-edge X-ray absorption near edge structure catalytic activity measurement. Cracking alkylation are facilitated carbenium initiated AlCl 3 - tert -butyl chloride (TBC) adducts, which formed dissociation 2 Cl 7 − presence TBC. The activate alkane polymer strands advance cycle multiple hydride transfer reactions. In 1 H NMR operando infrared spectroscopy demonstrate that cracking processes occur synchronously; alkenes during rapidly incorporated ion-mediated cycle. conclusions further supported ab initio molecular dynamics simulations coupled an enhanced sampling method, model experiments using n-hexadecane as feed.

Language: Английский

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