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

Peczak, Ian L; Kennedy, Robert M.; Hackler, Ryan A.; Lee, Byeongdu; Meirow, Max; Luijten, Erik; Poeppelmeier, Kenneth R.; Delferro, Massimiliano

doi:10.1016/j.matt.2023.06.038

Cited by 9 publications

(10 citation statements)

References 106 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…C{ 1 H} NMR properties consistent with complete loss of diastereoselectivity and formation of regioirregular errors under 1 atm H 2 . These results show that a Ziegler−Natta-type active site is compatible in a common reaction used to digest waste plastic into smaller aliphatic fragments.…”

mentioning

confidence: 65%

“…Most polyolefins reach end-of-life as unrecyclable waste. 1 Treating plastic waste with H 2 and a catalyst forms low molecular weight alkanes that could be processed back to the monomer, which is a plausible strategy to a circular plastics economy. These hydrogenolysis reactions are usually catalyzed by supported nanoparticles 2 or the heterogeneous "single-site" d 0 metal hydrides shown in Figure 1.…”

mentioning

confidence: 99%

“…Ziegler–Natta olefin polymerization reactions are the foundation of the plastics economy and produce millions of tons of highly versatile polyethylene or polypropylene products per year. Most polyolefins reach end-of-life as unrecyclable waste . Treating plastic waste with H 2 and a catalyst forms low molecular weight alkanes that could be processed back to the monomer, which is a plausible strategy to a circular plastics economy.…”

mentioning

confidence: 99%

See 2 more Smart Citations

A Supported Ziegler-Type Organohafnium Site Metabolizes Polypropylene

Samudrala,

Conley

2023

J. Am. Chem. Soc.

View full text Add to dashboard Cite

Cp2Hf(CH3)2 reacts with silica containing strong aluminum Lewis sites to form Cp2Hf–13CH3 + paired with aluminate anions. Solid-state NMR studies show that this reaction also forms neutral organohafnium and hafnium sites lacking methyl groups. Cp2Hf–13CH3 + reacts with isotatic polypropylene (iPP, M n = 13.3 kDa; Đ = 2.4; mmmm = 94%; ∼110 C3H6/Hf) and H2 to form oils with moderate molecular weights (M n = 290–1200 Da) in good yields. The aliphatic oils show characteristic 13C{1H} NMR properties consistent with complete loss of diastereoselectivity and formation of regioirregular errors under 1 atm H2. These results show that a Ziegler–Natta-type active site is compatible in a common reaction used to digest waste plastic into smaller aliphatic fragments.

show abstract

mentioning

confidence: 65%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

A Supported Ziegler-Type Organohafnium Site Metabolizes Polypropylene

Samudrala,

Conley

2023

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…For platinum-based hydrogenolysis catalysts, research has primarily focused on Pt/Al 2 O 3 , , Pt/C, and Pt/SiO 2 , based systems, with inconsistent hydrogenolysis conditions making direct comparison between different Pt/support combinations challenging (Table ). In a pioneering work, ,, Pt nanoparticles (NPs) supported on strontium titanate (SrTiO 3 ) perovskite nanocuboids by atomic layer deposition (ALD) were shown to be highly active hydrogenolysis catalysts, converting polyethylene (PE; M w = 17,200–420,000 g/mol and M n = 8,000–158,000 g/mol) into high-quality liquid hydrocarbon products ( M w = 500–960 g/mol and M n = 480–820 g/mol) under relatively mild conditions with 46–99% yield (300 °C, 170 psi H 2 , solvent-free). ,, In the same system, postconsumer plastic waste, including single-use plastic bags ( M w = 115,150 g/mol and M n = 33,000 g/mol) and bubble wrap ( M w = 824,200 g/mol), was converted into value-added lubricants and waxes ( M w = 450–1,130 g/mol and M n = 460–990 g/mol) with properties similar to synthetic base oils, such as polyalphaolefins (PAOs), and enhanced properties compared to petroleum-based lubricants, such as Group III mineral oil . Additionally, life cycle and techno-economic analyses found this hydrogenolysis process to be energetically efficient and potentially economically feasible …”

Section: Introductionmentioning

confidence: 99%

Supported Platinum Nanoparticles Catalyzed Carbon–Carbon Bond Cleavage of Polyolefins: Role of the Oxide Support Acidity

Lamb,

Lee,

Sun

et al. 2024

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Supported platinum nanoparticle catalysts are known to convert polyolefins to high-quality liquid hydrocarbons using hydrogen under relatively mild conditions. To date, few studies using platinum grafted onto various metal oxide (M x O y ) supports have been undertaken to understand the role of the acidity of the oxide support in the carbon−carbon bond cleavage of polyethylene under consistent catalytic conditions. Specifically, two Pt/M x O y catalysts (M x O y = SrTiO 3 and SiO 2 −Al 2 O 3 ; Al = 3.0 wt %, target Pt loading 2 wt % Pt ∼1.5 nm), under identical catalytic polyethylene hydrogenolysis conditions (T = 300 °C, P(H 2 ) = 170 psi, t = 24 h; M w = ∼3,800 g/mol, M n = ∼1,100 g/ mol, Đ = 3.45, N branch/100C = 1.0), yielded a narrow distribution of hydrocarbons with molecular weights in the range of lubricants (M w = < 600 g/mol; M n < 400 g/mol; Đ = 1.5). While Pt/SrTiO 3 formed saturated hydrocarbons with negligible branching, Pt/ SiO 2 −Al 2 O 3 formed partially unsaturated hydrocarbons (<1 mol % alkenes and ∼4 mol % alkyl aromatics) with increased branch density (N branch/100C = 5.5). Further investigations suggest evidence for a competitive hydrocracking mechanism occurring alongside hydrogenolysis, stemming from the increased acidity of Pt/SiO 2 −Al 2 O 3 compared to Pt/SrTiO 3 . Additionally, the products of these polymer deconstruction reactions were found to be independent of the polyethylene feedstock, allowing the potential to upcycle polyethylenes with various properties into a value-added product.

show abstract

“…4,[6][7][8][9] Breaking the C-C, C-O, or C-N bonds in polymer backbones enables the transformation of post-consumer plastics into building blocks for new materials. For example, hydrogenolysis of polyolens produces valuable products such as liquid fuels, waxes, and lubricants; [10][11][12] solvolysis of polyesters yields corresponding monomers or value-added derivatives; 4,[13][14][15][16] and polyamides can be catalytically converted to either 3-caprolactam by a chain-end backbiting process or alcohols and amines by hydrogenolysis. 17,18 Despite the progress, the depolymerization of waste plastics oen requires harsh conditions to achieve bond cleavage, undermining the economic viability of these processes.…”

Section: Introductionmentioning

confidence: 99%