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. 2024 Nov 21;146(48):33104–33111. doi: 10.1021/jacs.4c10793

Enhancing the Conversion Efficiency of Polyethylene to Methane through Codoping of Mn Atoms into Ru Centers and CeO2 Supports

Meng Zhao †,‡, Xiang Chu †,‡, Fei Wang †, Yizhu Fang †,‡, Lu Sun †,‡, Qing Xie †,‡, Ling-ling Zhang †,‡, Shuyan Song †,‡,*, Hongjie Zhang †,‡,§, Xiao Wang †,‡,*
PMCID: PMC11669166  PMID: 39571077

Abstract

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Chemical conversion has emerged as an effective approach for disposing waste plastics; however, the product diversity in traditional methods leads to pressing challenges in product separation and purification. As a pioneering advancement, the comprehensive transformation of waste plastics into CH4 presents an attractive prospect: directly yielding high-purity products. Significantly, CH4 is an important hydrogen carrier and an industrial feedstock. However, there is still much room for enhancing the overall efficiency. Herein, we show a new strategy to construct a high-efficiency and robust polyethylene (PE) upgrading catalyst by codoping Mn heteroatoms into both RuO2 and CeO2. We found that these Mn heteroatoms effectively bolster the stability of Ruδ+ species under high-temperature reduction conditions. The harmonious coexistence of Ru0 and Ruδ+ significantly refines the reaction pathway by enhancing the adsorption of the alkane intermediates. Consequently, we achieved an impressive PE conversion rate exceeding >99% with nearly 99% toward CH4 at a moderate temperature of 250 °C within 8 h. Our discovery not only opens a new window for catalyst upgrading but also presents exciting opportunities for the in-depth conversion of waste plastics into complex, high-purity fine chemicals through methane-mediated catalysis.

1. Introduction

Chemical conversion of waste plastics into value-added fuels and fine chemicals paves a new avenue to fight against white pollution and provide clean energy.1−8 The catalytic efficiency has been greatly improved by finely manipulating the reaction conditions and elaborately constructing the catalysts.9−13 A diverse array of products, encompassing saturated alkanes, olefins, and aromatic hydrocarbons, can be obtained through the conversion routes; however, these are always inherently mixtures, comprising a spectrum of homologues and isomers, leading to great difficulties in product separation. Therefore, significant efforts have been directed toward managing the unpredictable breakage patterns of lengthy plastic chains. Recently, a promising strategy has been proposed, emphasizing the comprehensive transformation of waste plastics into CH4, offering the potential to bypass costly separation methods and directly attain high-purity products. Significantly, CH4 is readily transformed into other crucial platform molecules like methanol through a well-established direct oxidation reaction.14−19 Otherwise, CH4 has the highest hydrogen content across all hydrocarbons. Its ease of storage and transportation renders it a highly promising hydrogen carrier.20,21 Exciting achievements have been made through a two-step tandem catalysis for converting plastic waste to CH4, entailing the pyrolysis of plastics into short-chain intermediates at 520 °C, followed by vaper-phase conversion.22 Taking into account the requirements for future scalable applications, undoubtedly, the one-step plastic-to-CH4 conversion under mild conditions would be more attractive, but it is still challenging.

Adhering to the Sabatier principle, the optimal interaction between a catalyst and its reactants necessitates a delicate balance, neither overly robust nor excessively feeble. Scientists have invested considerable effort to manipulate the surface state of the center metals, recognizing it as the pivotal determinant in the adsorption of substrate and intermediate molecules. The state-of-the-art investigations have underscored that catalytic processes are often driven synergistically by mixed-valence metals, as opposed to solely relying on a single valence-state center.23−28 For instance, Cu has garnered significant attention as a promising candidate in the selective hydrogenation of CO2 to methanol because it can generate highly active Cu0-Cu+ pairs during the catalytic process.29−32 When Pt0 and Pt+ species are coloaded on α-MoC for the water–gas shift reaction, they demonstrate a remarkable synergistic enhancement effect.33 Notably, the integration of metals with mixed-valence states into a single catalytic system offers a viable route for refining the reaction pathway. However, it is still challenging due to the inherent difficulties in simultaneously stabilizing the same metal ions in different oxidation states while meticulously maintaining a precise balance among them.

Herein, we reported a high-performance and robust polyethylene (PE) upgrading catalyst crafted by codoping Mn into RuO2 and CeO2 (denoted as RuMn/CeO2). Remarkably, the obtained RuMn/CeO2 catalysts exhibit excellent catalytic performance in PE upgrading, achieving over 99% PE conversion with a nearly 99% selectivity toward CH4 at a moderate temperature of 250 °C within 8 h. We further demonstrated the significance of the Mn heteroatoms, which greatly elevate the Ruδ+ content and improve its stability. The as-generated Ru0-Ruδ+ interface markedly strengthens the adsorption of alkane intermediates, thereby bolstering the overall catalytic performance.

2. Results and Discussion

2.1. Material Characterization

The RuMn/CeO2 catalyst was synthesized via a facile impregnation route, as illustrated schematically in Figure S1. Inductively coupled plasma mass spectrometry (ICP-MS) analysis reveals that the Ru and Mn contents are ∼2.5 and ∼2 wt %, respectively (Table S1). For better comparison, different kinds of Ru–Mn–CeO2 catalysts, including CeO2 nanorods (NRs)-supported Ru (Ru/CeO2), Mn-doped CeO2 (Mn-CeO2), and Mn-doped CeO2 supported Ru catalysts (Ru/Mn-CeO2) were also fabricated with similar Ru or Mn feeding amounts (Figures 1c,d, S2 and S3).

Figure 1.

Figure 1

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Fine structure characterizations. (a, c) High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of RuMn/CeO2 (a) and Ru/CeO2 (c). (b, d) Corresponding energy-dispersive X-ray (EDX) mappings. (e, f) k2-weighted Fourier transform extended X-ray absorption fine structure (EXAFS) spectrum of Mn K-edge and Ru K-edge.

The powder X-ray powder diffraction (XRD) spectrum reveals that RuMn/CeO2 comprises a composite structure of CeO2 and RuO2 crystals (Figure S4).34 No signal belonging to the separated Mn species was detected. According to Bragg’s law (2d sin θ = nλ), the average crystallite size of the RuO2 was calculated to be ∼1.7 nm. Transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) characterizations were further carried out to gain deep insight into the fine structure (Figures 1a and S5). The rod-like morphology with smooth surface is well maintained after calcination. Through a closer observation, the lattice parameter of RuMn/CeO2 was identified as 5.3818 Å, which is smaller than that of Ru/CeO2 (5.3897 Å), indicating the successful doping of Mn into CeO2 crystals (Table S2).35 There are no distinguished species belonging to Ru or Mn, possibly owing to their relatively low contrasts and high dispersity. The corresponding energy-dispersive X-ray (EDX) mapping analysis firmly confirms the successful incorporation of Ru and Mn elements, and all of the elements are homogeneously dispersed over the whole particle (Figure 1b).

X-ray absorption spectroscopy (XAS) measurement was used to determine the local chemical environment of Mn and Ru species (Figure S6, Tables S3 and S4). Figure S7a displays the Mn K-edge absorption near-edge structure (XANES) spectra for Mn foil, MnO, and RuMn/CeO2. The Mn species exist in a high oxidation state since the adsorption edge position for RuMn/CeO2 is at a higher energy than that of MnO. The XANES spectrum for Ru K-edge demonstrates that the Ru is cationic because of its noticeable higher energy adsorption compared with standard Ru foil (Figure S7b). Fourier transformed (FT) k2-weighted Mn K-edge extended X-ray absorption fine structure (EXAFS) was collected in Figure 1e. For RuMn/CeO2, the main peak is located at ∼1.94 Å, corresponding to the first-shell scattering path of the Mn–O bond. The CN was calculated to be 5.5 ± 0.2. Moreover, three relatively weak peaks emerge at approximately 2.45, 3.83, and 4.73 Å, which can be assigned to the second shell Mn–Ce, Mn–Ru, and Mn–Mn multiple scattering processes,36−39 indicating that the Mn species incorporate into both CeO2 supports and surface-loaded RuOx species. The Ru K-edge EXAFS fitting curves demonstrate a common feature in both the RuMn/CeO2 and Ru/CeO2 catalysts: a dominant Ru–O scattering path, accompanied by a minor contribution from Ru–Ru scattering (Figure 1f). Compared to Ru/CeO2, RuMn/CeO2 possesses a shortened Ru–O bond (2.00 Å) with the Ru–O CN enhanced from 4.1 ± 0.1 to 4.7 ± 0.2, and the CN of Ru–Ru CN decreased from 3.1 ± 0.2 to 2.0 ± 0.2. The changes are in accordance with the previous reports, demonstrating the successful doping of Mn into RuO2 crystals.40−42

2.2. Catalytic Performance Investigation

The polyolefin depolymerization reaction was carried out in a Parr batch reactor. Low-density polyethylene (LDPE, Mn: ∼1700, Mw: ∼4000) was chosen as the model substrate, and the hydrogenolysis process was performed at 250 °C, a relatively low temperature at which chemical depolymerization happens in the polymer melt. For each test, the carbon balance was controlled within the experimental error (±10%) (Table S5). With the data shown in Figure 2a and Table S6, the RuMn/CeO2 catalyst demonstrates remarkable catalytic prowess, achieving a full conversion of PE within 0.5 h under a hydrogen pressure of 10 bar. The yield of gas products exhibits a swift increase over time, culminating in an exceptional yield of over 99.9% within 6 h. Furthermore, we meticulously tracked the carbon distribution of the gas products every hour. Consistent with the trend in gas product yield, the selectivity toward CH4 steadily rose, peaking at an impressive 99.2% after 8 h (Figure 3b and Table S7), which is much better than Ru/CeO2 (Figure S8). We further investigated the effect of H2 pressure; it is noteworthy that elevating the reaction pressure leads to a marked decrease in CH4 selectivity (Figures S9–S13). This phenomenon finds its explanation in Le Chatelier’s principle, which posits that an increase in pressure is adverse to reactions that increase the number of gas molecules. The cycling performance was also investigated. After five cycles, the catalyst also achieves nearly 100% PE conversion with 90.1% CH4 selectivity (Figure S14). These results demonstrate the excellent catalytic stability of the obtained RuMn/CeO2 catalysts. In addition, we also attempted to operate the catalysis with other substrates, including high-density polyethylene (HDPE, Mw ∼ 200,000) and PE wax (Mw ∼ 13,000). Remarkably, both feedstocks can be converted into CH4 with high efficiency (Figure S15).

Figure 2.

Figure 2

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Catalytic performance investigations. (a, b) Time-programmed LDPE hydrogenolysis performance and the corresponding CH4 yields of RuMn/CeO2. (c) Catalytic performance comparison of the samples with various Mn content. (d) Performance comparison over prepared catalysts, including RuMn/CeO2, Ru/CeO2, Ru/Mn-CeO2, physically mixed Ru/CeO2 and Mn/CeO2, Ru/MnO2, and RuCe/MnO2. (Conditions: 10 bar H2, 250 °C, 0.08 g catalysts, 0.8 g LDPE).

Figure 3.

Figure 3

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Study the Mn promotion effect. (a) Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) spectra, (b) H2-TPD profile, and (c, d) in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy of PE hydrogenolysis reaction over RuMn/CeO2 and Ru/CeO2 catalysts.

Subsequently, we performed a control experiment by adjusting the Mn doping concentration. As shown in Figure 2c, the gas product fraction exhibits a volcanic curve with an increase of the Mn content. For the lowest Mn loading (0.2 wt %), while the polyethylene (PE) conversion remains constant at 100%, the selectivity toward methane (CH4) abruptly declines to 58.3% within 8 h, underscoring the crucial role of Mn heteroatoms in C–C bond breaking. In contrast, for the highest Mn loading (10 wt %), the PE conversion decreases to 78.4% accompanied by a relatively low CH4 selectivity of 21.3%, which may be attributed to the blocking effect caused by an excess of Mn (Figure S16). Additionally, we delved into the influence of post-treatment methods toward catalytic performance (Figure S17). When the RuMn/CeO2 catalysts were further calcined at 550 in H2/Ar mixed gas, the selectivity of gas products decreases to 38.9%, while the selectivity of liquid and solid products increases to 24.8 and 36.3%, respectively. These findings highlight the paramount importance of the partial oxidation surface state of Ru in optimizing the PE-to-CH4 conversion process.

For a better comparison, the catalytic properties of the reference samples were evaluated. As illustrated in Figure 2d, under the same conditions, the Ru/CeO2 catalyst yields merely 55.2% of the targeted CH4 product, whereas the Ru/Mn-CeO2 catalyst gives a higher CH4 yield of 58.9%. However, both of these yields pale in comparison to that achieved by the RuMn/CeO2 catalyst, emphasizing the paramount importance of codoping Mn atoms into both CeO2 and RuO2 for significant enhancement in catalytic activity. Meanwhile, we attempted to use physically mixed Ru/CeO2 and Mn/CeO2 as catalysts. The overall efficiency is relatively poor, suggesting the crucial role of the distance between the Ru and Mn species. We also synthesized MnO2-supported Ru (Ru/MnO2), MnO2-supported Ce-promoted Ru (RuCe/MnO2), SiO2-supported Mn-doped RuO2, and SiO2-supported RuO2 (Figure S18). Obviously, very little PE is converted, suggesting the significance of CeO2 as a support material in PE upgrading.

2.3. Structure-Performance Investigation

In situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was first conducted to study the reaction pathways. Characteristic LDPE vibrations, including Vas(CH2) at 2930 cm–1 and Vs(CH2) at 2850 cm–1, were identified and their intensity changes are associated with the cracking rate of PE polymer chains.43 For RuMn/CeO2, the intensity decreased sharply. In contrast, the intensity changes are relatively slight over the Ru/CeO2 catalyst, confirming the Mn promotion effect in PE conversion (Figure 3c,d). We further explored the structure evolution during the catalytic process by near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) analysis. With the data shown in Figures 3a and S19, the Ru 3p peaks can be fitted into three peaks according to their binding energies, corresponding to Ru 3p3/2 and Ru 3p1/2.44 The Ru0 content of RuMn/CeO2 was calculated to be 0.24, which is much smaller than that of Ru/CeO2 (0.43). Otherwise, the oxygen vacancy content of RuMn/CeO2 is much higher than that of Ru/CeO2 (0.15 vs 0.09). These results indicate that the incorporation of Mn significantly improves the surface state of the catalysts.

Density functional theory (DFT) simulations were then carried out to investigate the influence of Mn atoms on the structural stability of RuO2 (Figure S20). The total energy of the system (E) and the Ru–O bond length (R) were selected as the key parameters to assess the stability. All of these models present similar E and R values with the number of Mn atoms increasing from 1 to 6, elucidating that the small content of Mn doping is thermodynamics permitted for RuO2 lattice. Further increasing the number of Mn atoms leads to a rapid accumulation of lattice stress, ultimately resulting in the complete collapse of the RuO2 lattice when the doping level of Mn reaches 9. We further investigated the changes in hydrogen adsorption energy on Ru species as the doping level of the Mn atom varies (Figure S21). As the number of Mn dopant atoms surrounding the Ru atom increases, the adsorption capacity of the Ru atom for hydrogen molecule decreases significantly, suggesting a substantial decrease in the reducibility of Ruδ+, which fundamentally explains the stabilizing effect of Mn atoms on Ruδ+.

The H2-TPD spectra present notable differences (Figure 3b), where the utilized RuMn/CeO2 catalyst exhibits a prominent desorption peak at 222 °C, in stark contrast to the more intense peak at 396 °C observed for the used Ru/CeO2. The finding underscores that the introduction of Mn significantly improves the H2 desorption capability. Previous literature shows that a reduced H2 desorption capability facilitates H-spillover, which, in turn, promotes the hydrogenation process.45,46 The following H-spillover experiments also confirm the crucial role of Mn heteroatoms for H-spillover behaviors (Figure S22). Therefore, the disparity in H2 desorption between the two catalysts is considered to be one of the primary factors underpinning their distinct catalytic performance. Differing from H2-TPD, the C3H8-TPD spectra reveal that the C3H8 desorption peak of the used RuMn/CeO2 shifts to a higher temperature compared with the used Ru/CeO2, demonstrating the remarkable capacity of RuMn/CeO2 for C3H8 adsorption (Figure S16c). Given that the hydrogenolysis rate of PE is intimately tied to the strength of PE molecule adsorption on catalysts, the enhanced alkane-adsorption behavior of RuMn/CeO2 is thus recognized as another key contributor to its improved catalytic performance.

For better understanding the relationship between Ru surface state and catalytic behavior, we further calculated the adsorption energies of C3H8 on various catalysts.47,48 Considering the relatively inland positions of Mn elements and the coexistence of Ru0 and Ruδ+, a simplified structure was constructed, whereby a small cluster of RuOx is loaded on the Ru bulk. For starters, the most favorable adsorption modes and the adsorption energy of H2 and C3H8 are presented in Figures 4a and S23. The H2 molecule is strongly absorbed and subsequently dissociated into two H atoms on the surface of Ru NP with an adsorption energy of −1.33 eV. In contrast, on the interface of Ru-RuOx where one of the dissociated H atoms is bonded to the Ru atom of Ru NP and the other H is absorbed by the Ru atom of RuOx, the adsorption energy of H2 is only −0.31 eV, which is far less than the adsorption energy of H2 on Ru NP. Therefore, compared to the RuOx, Ru NP is the main H2 adsorption site in the catalyst. Meanwhile, the adsorption configuration of C3H8 in the interface is most stable with an adsorption energy of −1.43 eV. It indicates that the formation of the Ru-RuOx interface on the catalyst can effectively enhance the C3H8 adsorption capacity. The results imply that the coeffect of Ru0 and Ruδ+ species would reinforce the interaction between the LDPE molecule and the catalyst surface. This is also theoretical evidence that the hydrogenation activity of RuMn/CeO2 was higher than that of Ru/CeO2.

Figure 4.

Figure 4

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DFT simulation of the structure-performance relationship. (a) Adsorption configuration of H2 (left) and C3H8 (right) over the Ru/RuOx model structure. (b) Reaction energy profile on the Ru/RuOx model structure. (c) The corresponding reaction pathways.

To gain deeper insight into the complete evolution path of C3H8 on the Ru0-Ruδ+ interface, the reaction energy profile was simulated (Figure 4b,c). The adsorbed *C3H8 (ii) is first dissociated into *C3H7 + *H (iii), which demands +0.30 eV thermodynamically. This is the most endothermal step in view of the fact that the free energy changes for other elementary steps are either downhill or with smaller uphill energy. In the following step, the C–C bond of *C3H7 is broken into *CH2 + *C2H5 + *H (iv) with an energy of −0.26 eV, as reflected with a downhill step in the reaction energy profile. The obtained *CH2 was rapidly hydrogenated to *CH3 (v). Following a H2 dissociation step, the absorbed*C2H5 and *CH3 were hydrogenated to C2H6 (vii) and CH4 (viii) with uphill energies of +0.17 and +0.20 eV, respectively. This is in good accordance with the experimental observation whereby the RuMn/CeO2 overwhelms.

3. Conclusions

We have demonstrated that the content of oxidized Ru species in the reduction atmosphere could be greatly improved by incorporating heteroatoms into the RuO2 lattice. More importantly, the coexistence of Ru0 and Ruδ+ is essential for the efficient conversion of PE into CH4. In this process, Ru0 serves as the active site for H2 activation, while Ruδ+ plays a crucial role in adsorbing alkane intermediates. This discovery not only unlocks fresh avenues for catalyst design and engineering but also presents intriguing prospects for the profound conversion of waste PE into sophisticated, high-purity fine chemicals through methane-mediated catalysis. This finding holds immense potential for the sustainable utilization of plastic waste.

Acknowledgments

This work was supported by the financial aid from National Science and Technology Major Project of China (2022YFB3504000), National Natural Science Foundation of China (22020102003, 22025506, and 22271274), and Program of Science and Technology Development Plan of Jilin Province of China (20240402056GH). X.W. acknowledges funding from National Natural Science Foundation of China Outstanding Youth Science Foundation of China (Overseas).

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.4c10793.

  • Experimental procedure, tests of sample, and DFT computational details and characterizations (PDF)

The authors declare no competing financial interest.

Supplementary Material

ja4c10793_si_001.pdf (2.9MB, pdf)

References

  1. Miao Y.; Zhao Y.; Waterhouse G. I. N.; Shi R.; Wu L.; Zhang T. Photothermal recycling of waste polyolefin plastics into liquid fuels with high selectivity under solvent-free conditions. Nat. Commun. 2023, 14 (1), 4242 10.1038/s41467-023-40005-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Zhao X.; Boruah B.; Chin K. F.; Đokić M.; Modak J. M.; Soo H. S. Upcycling to Sustainably Reuse Plastics. Adv. Mater. 2022, 34 (25), 2100843 10.1002/adma.202100843. [DOI] [PubMed] [Google Scholar]
  3. Li L.; Luo H.; Shao Z.; Zhou H.; Lu J.; Chen J.; Huang C.; Zhang S.; Liu X.; Xia L.; Li J.; Wang H.; Sun Y. Converting Plastic Wastes to Naphtha for Closing the Plastic Loop. J. Am. Chem. Soc. 2023, 145 (3), 1847–1854. 10.1021/jacs.2c11407. [DOI] [PubMed] [Google Scholar]
  4. Zhou H.; Wang Y.; Ren Y.; Li Z.; Kong X.; Shao M.; Duan H. Plastic Waste Valorization by Leveraging Multidisciplinary Catalytic Technologies. ACS Catal. 2022, 12 (15), 9307–9324. 10.1021/acscatal.2c02775. [DOI] [Google Scholar]
  5. Sajwan D.; Sharma A.; Sharma M.; Krishnan V. Upcycling of Plastic Waste Using Photo-, Electro-, and Photoelectrocatalytic Approaches: A Way toward Circular Economy. ACS Catal. 2024, 14 (7), 4865–4926. 10.1021/acscatal.4c00290. [DOI] [Google Scholar]
  6. Martín A. J.; Mondelli C.; Jaydev S. D.; Pérez-Ramírez J. Catalytic processing of plastic waste on the rise. Chem 2021, 7 (6), 1487–1533. 10.1016/j.chempr.2020.12.006. [DOI] [Google Scholar]
  7. Jiao X.; Zheng K.; Hu Z.; Zhu S.; Sun Y.; Xie Y. Conversion of Waste Plastics into Value-Added Carbonaceous Fuels under Mild Conditions. Adv. Mater. 2021, 33 (50), 2005192 10.1002/adma.202005192. [DOI] [PubMed] [Google Scholar]
  8. Hu Q.; Zhang Z.; He D.; Wu J.; Ding J.; Chen Q.; Jiao X.; Xie Y. Progress and Perspective for “Green” Strategies of Catalytic Plastics Conversion into Fuels by Regulating Half-Reactions. J. Am. Chem. Soc. 2024, 146 (25), 16950–16962. 10.1021/jacs.4c04848. [DOI] [PubMed] [Google Scholar]
  9. Rorrer J. E.; Beckham G. T.; Román-Leshkov Y. Conversion of Polyolefin Waste to Liquid Alkanes with Ru-Based Catalysts under Mild Conditions. JACS Au 2021, 1 (1), 8–12. 10.1021/jacsau.0c00041. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Jia C.; Xie S.; Zhang W.; Intan N. N.; Sampath J.; Pfaendtner J.; Lin H. Deconstruction of high-density polyethylene into liquid hydrocarbon fuels and lubricants by hydrogenolysis over Ru catalyst. Chem. Catal. 2021, 1 (2), 437–455. 10.1016/j.checat.2021.04.002. [DOI] [Google Scholar]
  11. Nakaji Y.; Tamura M.; Miyaoka S.; Kumagai S.; Tanji M.; Nakagawa Y.; Yoshioka T.; Tomishige K. Low-temperature catalytic upgrading of waste polyolefinic plastics into liquid fuels and waxes. Appl. Catal., B 2021, 285, 119805 10.1016/j.apcatb.2020.119805. [DOI] [Google Scholar]
  12. Chen L.; Zhu Y.; Meyer L. C.; Hale L. V.; Le T. T.; Karkamkar A.; Lercher J. A.; Gutiérrez O. Y.; Chemistry J. J. R. Effect of reaction conditions on the hydrogenolysis of polypropylene and polyethylene into gas and liquid alkanes. React. Chem. Eng. 2022, 7 (4), 844–854. 10.1039/D1RE00431J. [DOI] [Google Scholar]
  13. Wu X.; Wang X.; Zhang L.; Wang X.; Song S.; Zhang H. Polyethylene Upgrading to Liquid Fuels Boosted by Atomic Ce Promoters. Angew. Chem. 2024, 63 (8), e202317594 10.1002/ange.202317594. [DOI] [PubMed] [Google Scholar]
  14. Conrado R. J.; Gonzalez R. Envisioning the Bioconversion of Methane to Liquid Fuels. Science 2014, 343 (6171), 621–623. 10.1126/science.1246929. [DOI] [PubMed] [Google Scholar]
  15. Li Q.; Ouyang Y.; Li H.; Wang L.; Zeng J. Photocatalytic Conversion of Methane: Recent Advancements and Prospects. Angew. Chem. 2022, 61 (2), e202108069 10.1002/ange.202108069. [DOI] [PubMed] [Google Scholar]
  16. Kim J.; Kim J. H.; Oh C.; Yun H.; Lee E.; Oh H.-S.; Park J. H.; Hwang Y. J. Electro-assisted methane oxidation to formic acid via in-situ cathodically generated H2O2 under ambient conditions. Nat. Commun. 2023, 14 (1), 4704 10.1038/s41467-023-40415-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Murray E. P.; Tsai T.; Barnett S. A. A direct-methane fuel cell with a ceria-based anode. Nature 1999, 400 (6745), 649–651. 10.1038/23220. [DOI] [Google Scholar]
  18. Cargnello M.; Jaén J. J. D.; Garrido J. C. H.; Bakhmutsky K.; Montini T.; Gámez J. J. C.; Gorte R. J.; Fornasiero P. Exceptional Activity for Methane Combustion over Modular Pd@CeO2 Subunits on Functionalized Al2O3. Science 2012, 337 (6095), 713–717. 10.1126/science.1222887. [DOI] [PubMed] [Google Scholar]
  19. Murata K.; Mahara Y.; Ohyama J.; Yamamoto Y.; Arai S.; Satsuma A. The Metal-Support Interaction Concerning the Particle Size Effect of Pd/Al2O3 on Methane Combustion. Angew. Chem., Int. Ed. 2017, 56 (50), 15993–15997. 10.1002/anie.201709124. [DOI] [PubMed] [Google Scholar]
  20. Chen L.; Song Z.; Zhang S.; Chang C.; Chuang Y.; Peng X.; Dun C.; Urban J. J.; Guo J.; Chen J.; Prendergast D.; Salmeron M.; Somorjai G. A.; Su J. Ternary NiMo-Bi liquid alloy catalyst for efficient hydrogen production from methane pyrolysis. Science 2023, 381 (6660), 857–861. 10.1126/science.adh8872. [DOI] [PubMed] [Google Scholar]
  21. Upham D. C.; Agarwal V.; Khechfe A.; Snodgrass Z. R.; Gordon M. J.; Metiu H.; McFarland E. W. Catalytic molten metals for the direct conversion of methane to hydrogen and separable carbon. Science 2017, 358 (6365), 917–921. 10.1126/science.aao5023. [DOI] [PubMed] [Google Scholar]
  22. Zhang Z.; Wang J.; Ge X.; Wang S.; Li A.; Li R.; Shen J.; Liang X.; Gan T.; Han X.; Zheng X.; Duan X.; Wang D.; Jiang J.; Li Y. Mixed Plastics Wastes Upcycling with High-Stability Single-Atom Ru Catalyst. J. Am. Chem. Soc. 2023, 145 (41), 22836–22844. 10.1021/jacs.3c09338. [DOI] [PubMed] [Google Scholar]
  23. Hu P.; Zhang C.; Chu M.; Wang X.; Wang L.; Li Y.; Yan T.; Zhang L.; Ding Z.; Cao M.; Xu P.; Li Y.; Cui Y.; Zhang Q.; Chen J.; Chi L. Stable Interfacial Ruthenium Species for Highly Efficient Polyolefin Upcycling. J. Am. Chem. Soc. 2024, 146 (10), 7076–7087. 10.1021/jacs.4c00757. [DOI] [PubMed] [Google Scholar]
  24. Yu J.; Qin X.; Yang Y.; Lv M.; Yin P.; Wang L.; Ren Z.; Song B.; Li Q.; Zheng L.; Hong S.; Xing X.; Ma D.; Wei M.; Duan X. Highly Stable Pt/CeO2 Catalyst with Embedding Structure toward Water-Gas Shift Reaction. J. Am. Chem. Soc. 2024, 146 (1), 1071–1080. 10.1021/jacs.3c12061. [DOI] [PubMed] [Google Scholar]
  25. Shao Z.; Zhang S.; Liu X.; Luo H.; Huang C.; Zhou H.; Wu Z.; Li J.; Wang H.; Sun Y. Maximizing the synergistic effect between Pt0 and Ptδ+ in a confined Pt-based catalyst for durable hydrogen production. Appl. Catal., B 2022, 316, 121669 10.1016/j.apcatb.2022.121669. [DOI] [Google Scholar]
  26. Hu B.; Warczinski L.; Li X.; Lu M.; Bitzer J.; Heidelmann M.; Eckhard T.; Fu Q.; Schulwitz J.; Merko M.; Li M.; Kleist W.; Hättig C.; Muhler M.; Peng B. Formic Acid-Assisted Selective Hydrogenolysis of 5-Hydroxymethylfurfural to 2,5-Dimethylfuran over Bifunctional Pd Nanoparticles Supported on N-Doped Mesoporous Carbon. Angew. Chem., Int. Ed. 2021, 60 (12), 6807–6815. 10.1002/anie.202012816. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Meng H.; Yang Y.; Shen T.; Yin Z.; Zhang J.; Yan H.; Wei M. Highly Efficient Hydrogen Production from Dehydrogenation Reaction of Nitrogen Heterocycles via Pd0-Pdδ+ Synergistic Catalysis. ACS Catal. 2023, 13 (13), 9234–9244. 10.1021/acscatal.3c01522. [DOI] [Google Scholar]
  28. Do V.-H.; Prabhu P.; Jose V.; Yoshida T.; Zhou Y.; Miwa H.; Kaneko T.; Uruga T.; Iwasawa Y.; Lee J.-M. Pd-PdO Nanodomains on Amorphous Ru Metallene Oxide for High-Performance Multifunctional Electrocatalysis. Adv. Mater. 2023, 35 (12), 2208860 10.1002/adma.202208860. [DOI] [PubMed] [Google Scholar]
  29. Zhao H.; Yu R.; Ma S.; Xu K.; Chen Y.; Jiang K.; Fang Y.; Zhu C.; Liu X.; Tang Y.; Wu L.; Wu Y.; Jiang Q.; He P.; Liu Z.; Tan L. The role of Cu1-O3 species in single-atom Cu/ZrO2 catalyst for CO2 hydrogenation. Nat. Catal. 2022, 5 (9), 818–831. 10.1038/s41929-022-00840-0. [DOI] [Google Scholar]
  30. Fernández-Villanueva E.; Lustemberg P. G.; Zhao M.; Soriano Rodriguez J.; Concepción P.; Ganduglia-Pirovano M. V. Water and Cu+ Synergy in Selective CO2 Hydrogenation to Methanol over Cu-MgO-Al2O3 Catalysts. J. Am. Chem. Soc. 2024, 146 (3), 2024–2032. 10.1021/jacs.3c10685. [DOI] [PubMed] [Google Scholar]
  31. Wang Q.-N.; Duan R.; Feng Z.; Zhang Y.; Luan P.; Feng Z.; Wang J.; Li C. Understanding the Synergistic Catalysis in Hydrogenation of Carbonyl Groups on Cu-Based Catalysts. ACS Catal. 2024, 14 (3), 1620–1628. 10.1021/acscatal.3c04740. [DOI] [Google Scholar]
  32. Yuan X.; Chen S.; Cheng D.; Li L.; Zhu W.; Zhong D.; Zhao Z.-J.; Li J.; Wang T.; Gong J. Controllable Cu0-Cu+ Sites for Electrocatalytic Reduction of Carbon Dioxide. Angew. Chem., Int. Ed. 2021, 60 (28), 15344–15347. 10.1002/anie.202105118. [DOI] [PubMed] [Google Scholar]
  33. Zhang X.; Zhang M.; Deng Y.; Xu M.; Artiglia L.; Wen W.; Gao R.; Chen B.; Yao S.; Zhang X.; Peng M.; Yan J.; Li A.; Jiang Z.; Gao X.; Cao S.; Yang C.; Kropf A. J.; Shi J.; Xie J.; Bi M.; van Bokhoven J. A.; Li Y.-W.; Wen X.; Flytzani-Stephanopoulos M.; Shi C.; Zhou W.; Ma D. A stable low-temperature H2-production catalyst by crowding Pt on α-MoC. Nature 2021, 589 (7842), 396–401. 10.1038/s41586-020-03130-6. [DOI] [PubMed] [Google Scholar]
  34. Song H.; Yong X.; Waterhouse G. I. N.; Yu J.; Wang H.; Cai J.; Tang Z.; Yang B.; Chang J.; Lu S. RuO2-CeO2 Lattice Matching Strategy Enables Robust Water Oxidation Electrocatalysis in Acidic Media via Two Distinct Oxygen Evolution Mechanisms. ACS Catal. 2024, 14 (5), 3298–3307. 10.1021/acscatal.3c06182. [DOI] [Google Scholar]
  35. Li H.; Lu G.; Dai Q.; Wang Y.; Guo Y.; Guo Y. Efficient low-temperature catalytic combustion of trichloroethylene over flower-like mesoporous Mn-doped CeO2 microspheres. Appl. Catal., B 2011, 102 (3), 475–483. 10.1016/j.apcatb.2010.12.029. [DOI] [Google Scholar]
  36. Li Y.; Qin T.; Xiong J.; Zhang P.; Ma Y.; Zhang S.; Liu X.; Zhao Z.; Liu J.; Chen L.; Wei Y. Mn-modified near-surface atomic structure of CeO2 nanorods for promoting catalytic oxidation of auto-exhaust carbon particles. Chem. Eng. Sci. 2023, 282, 119309 10.1016/j.ces.2023.119309. [DOI] [Google Scholar]
  37. Gevers L. E.; Enakonda L. R.; Shahid A.; Ould-Chikh S.; Silva C. I. Q.; Paalanen P. P.; Aguilar-Tapia A.; Hazemann J.-L.; Hedhili M. N.; Wen F.; Ruiz-Martínez J. Unraveling the structure and role of Mn and Ce for NOx reduction in application-relevant catalysts. Nat. Commun. 2022, 13 (1), 2960. 10.1038/s41467-022-30679-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Zhang D.; Li M.; Yong X.; Song H.; Waterhouse G. I. N.; Yi Y.; Xue B.; Zhang D.; Liu B.; Lu S. Construction of Zn-doped RuO2 nanowires for efficient and stable water oxidation in acidic media. Nat. Commun. 2023, 14 (1), 2517 10.1038/s41467-023-38213-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Li L.; Bu L.; Huang B.; Wang P.; Shen C.; Bai S.; Chan T.-S.; Shao Q.; Hu Z.; Huang X. Compensating Electronic Effect Enables Fast Site-to-Site Electron Transfer over Ultrathin RuMn Nanosheet Branches toward Highly Electroactive and Stable Water Splitting. Adv. Mater. 2021, 33 (51), 2105308 10.1002/adma.202105308. [DOI] [PubMed] [Google Scholar]
  40. Chen S.; Huang H.; Jiang P.; Yang K.; Diao J.; Gong S.; Liu S.; Huang M.; Wang H.; Chen Q. Mn-Doped RuO2 Nanocrystals as Highly Active Electrocatalysts for Enhanced Oxygen Evolution in Acidic Media. ACS Catal. 2020, 10 (2), 1152–1160. 10.1021/acscatal.9b04922. [DOI] [Google Scholar]
  41. Zheng C. X.; Huang B.; Liu X. W.; Wang H.; Guan L. H. Mn-doped RuO2 nanocrystals with abundant oxygen vacancies for enhanced oxygen evolution in acidic media. Inorg. Chem. Front. 2024, 11 (6), 1912–1922. 10.1039/D4QI00013G. [DOI] [Google Scholar]
  42. Zhou C.; Chen X.; Liu S.; Han Y.; Meng H.; Jiang Q.; Zhao S.; Wei F.; Sun J.; Tan T.; Zhang R. Superdurable Bifunctional Oxygen Electrocatalyst for High-Performance Zinc-Air Batteries. J. Am. Chem. Soc. 2022, 144 (6), 2694–2704. 10.1021/jacs.1c11675. [DOI] [PubMed] [Google Scholar]
  43. Zhou Q.; Wang D.; Wang Q.; He K.; Lim K. H.; Yang X.; Wang W.-J.; Li B.-G.; Liu P. Mechanistic Understanding of Efficient Polyethylene Hydrocracking over Two-Dimensional Platinum-Anchored Tungsten Trioxide. Angew. Chem., Int. Ed. 2023, 62 (40), e202305644 10.1002/anie.202305644. [DOI] [PubMed] [Google Scholar]
  44. Morgan D. J. Resolving ruthenium: XPS studies of common ruthenium materials. Surf. Interface Anal. 2015, 47 (11), 1072–1079. 10.1002/sia.5852. [DOI] [Google Scholar]
  45. Xia S.; Yuan Z.; Wang L.; Chen P.; Hou Z. Hydrogenolysis of glycerol on bimetallic Pd-Cu/solid-base catalysts prepared via layered double hydroxides precursors. Appl. Catal., A 2011, 403 (1), 173–182. 10.1016/j.apcata.2011.06.026. [DOI] [Google Scholar]
  46. Guo Y.; Mei S.; Yuan K.; Wang D.-J.; Liu H.-C.; Yan C.-H.; Zhang Y.-W. Low-Temperature CO2 Methanation over CeO2-Supported Ru Single Atoms, Nanoclusters, and Nanoparticles Competitively Tuned by Strong Metal–Support Interactions and H-Spillover Effect. ACS Catal. 2018, 8 (7), 6203–6215. 10.1021/acscatal.7b04469. [DOI] [Google Scholar]
  47. Chen S.; Tennakoon A.; You K.-E.; Paterson A. L.; Yappert R.; Alayoglu S.; Fang L.; Wu X.; Zhao T. Y.; Lapak M. P.; Saravanan M.; Hackler R. A.; Wang Y.-Y.; Qi L.; Delferro M.; Li T.; Lee B.; Peters B.; Poeppelmeier K. R.; Ammal S. C.; Bowers C. R.; Perras F. A.; Heyden A.; Sadow A. D.; Huang W. Ultrasmall amorphous zirconia nanoparticles catalyse polyolefin hydrogenolysis. Nat. Catal. 2023, 6 (2), 161–173. 10.1038/s41929-023-00910-x. [DOI] [Google Scholar]
  48. Xie T.; Wittreich G. R.; Vlachos D. G. Multiscale modeling of hydrogenolysis of ethane and propane on Ru (0001): Implications for plastics recycling. Appl. Catal., B 2022, 316, 121597 10.1016/j.apcatb.2022.121597. [DOI] [Google Scholar]

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