Pt nanoparticles embedded in CeO2 and CeZrO2 catalysts for biogas upgrading: Investigation on carbon removal mechanism by oxygen isotopic exchange and DRIFTS

Marinho, A. L. A.; Rabelo‐Neto, Raimundo C.; Epron, Florence; Bion, Nicolas; Noronha, Fábio B.; Toniolo, Fabio Souza

doi:10.1016/j.jcou.2021.101572

Cited by 10 publications

(9 citation statements)

References 66 publications

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“…Though there was a clear occurrence of the RWGS reaction (H2/CO ratio ~0.5 mol/mol), the Ni-SiO2@CeO2 showed a superior carbon oxidation capacity (0.047gC/gcatalyst after 72 h) due to the synergic Ni-CeO2 interaction that, as evidenced by in situ DRIFTS analysis, surprisingly changed the dry reforming reaction pathway (Figure 5). Similar results were obtained from Marinho et al [113] for Pt@CeO2 and Pt@CeZrO2. The formation of an embedded structure enhances the extent of ceria reduction and the creation of oxygen vacancies on the catalyst surface.…”

Section: Metal Oxides As Activity Promoterssupporting

confidence: 91%

“…Ni-CeO2 catalysts were also applied in combined steam and dry reforming in a recent work by Gao et al [114]. A ZSM-5 support was chosen to deposit Ni-CeO2 because of its Similar results were obtained from Marinho et al [113] for Pt@CeO2 and Pt@CeZrO2. The formation of an embedded structure enhances the extent of ceria reduction and the creation of oxygen vacancies on the catalyst surface.…”

Section: Metal Oxides As Activity Promotersmentioning

confidence: 81%

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Catalytic Upgrading of Clean Biogas to Synthesis Gas

et al. 2022

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Clean biogas, produced by anaerobic digestion of biomasses or organic wastes, is one of the most promising substitutes for natural gas. After its purification, it can be valorized through different reforming processes that convert CH4 and CO2 into synthesis gas (a mixture of CO and H2). However, these processes have many issues related to the harsh conditions of reaction used, the high carbon formation rate and the remarkable endothermicity of the reforming reactions. In this context, the use of the appropriate catalyst is of paramount importance to avoid deactivation, to deal with heat issues and mild reaction conditions and to attain an exploitable syngas composition. The development of a catalyst with high activity and stability can be achieved using different active phases, catalytic supports, promoters, preparation methods and catalyst configurations. In this paper, a review of the recent findings in biogas reforming is presented. The different elements that compose the catalytic system are systematically reviewed with particular attention on the new findings that allow to obtain catalysts with high activity, stability, and resistance towards carbon formation.

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Section: Metal Oxides As Activity Promoterssupporting

confidence: 91%

Section: Metal Oxides As Activity Promotersmentioning

confidence: 81%

Catalytic Upgrading of Clean Biogas to Synthesis Gas

et al. 2022

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“…The distribution and coordination transformation of varied Pt 1 O n –Ce δ+ species are further investigated by Raman spectroscopy (Figure a). All catalysts show an intense band at 463 cm –1 of the CeO 2 support, which is attributed to the F 2g band associating with the symmetrical stretching of the Ce–O bonds in the cubic [CeO 8 ] unit. , The upshift of the F 2g band on Pt/CeO 2 SACs (Figure S6) is attributed to the incorporation of Pt SAs into the CeO 2 lattice . Other than the F 2g band, three additional Raman vibrational modes are identified by bands at ∼300, ∼520, and ∼680 cm –1 , which are associated with the characteristic peaks of the Pt–O/Pt–O–Ce linkage , (Figure a).…”

Section: Resultsmentioning

confidence: 92%

“…29,30 The upshift of the F 2g band on Pt/CeO 2 SACs (Figure S6) is attributed to the incorporation of Pt SAs into the CeO 2 lattice. 31 Other than the F 2g band, three additional Raman vibrational modes are identified by bands at ∼300, ∼520, and ∼680 cm −1 , which are associated with the characteristic peaks of the Pt−O/Pt−O− Ce linkage 32,33 (Figure 3a). According to literatures, bands at ∼300 and 520 cm −1 are ascribed to the asymmetric vibration of the Pt−O−Ce linkage, while the band at 680 cm −1 is attributed to the Pt−O species with the square-planar coordinated Pt 2+ ion formed on the CeO 2 surface.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Reversible Transformation and Distribution Determination of Diverse Pt Single-Atom Species

Ding

et al. 2023

J. Am. Chem. Soc.

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In single-atom catalysts (SACs), the complexity of the support anchoring sites creates a vast diversity of single-atom species with varied coordination environments. To date, the quantitative distribution of these diverse single-atom species in a given SAC has remained elusive. Recently, CeO2-supported metal SACs have been extensively studied by modulating their local environments via numerous synthetic strategies. However, owing to the absence of a quantitative description, unraveling the site-specific reactivity and regulating their transformation remain challenging. Here, we show that two distinct Pt/CeO2 SACs can be reversibly generated by oxidative and nonoxidative dispersions, which contain varied Pt1O n –Ceδ+ single-atom species despite similar Pt charge states and coordination numbers. By means of Raman spectroscopy and computational studies, we semiquantitatively reveal the distribution of diverse Pt1O n –Ceδ+ species in each specific SACs. Remarkably, the minority species of Pt1O4–Ce3+–Ov accounting for only 14.2% affords the highest site-specific reactivity for low-temperature CO oxidation among the other abundant counterparts, i.e., Pt1O4–Ce4+ and Pt1O6–Ce4+. The second nearest oxygen vacancy (Ov) not only acts synergistically with the nearby active metal sites to lower the reaction barrier but also facilitates the dynamic transformation from six-coordinated to four-coordinated sites during cyclic nonoxidative and oxidative dispersions. This work elucidates the quantitative distribution and dynamic transformation of varied single-atom species in a given SAC, offering a more intrinsic descriptor and quantitative measure to depict the inhomogeneity of SACs.

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“…The high temperature required to obtain high syngas yield is also responsible for the sintering of the active site and/or the support [6][7][8][9][10][11]. MDR was widely studied on supported noble metal (Ru, Rh, Pd, Pt, Ir) catalysts, which are active and generally resistant to the formation of carbon, but their high costs restrict their industrial application [1,2,[12][13][14][15]. Non-noble metal (Ni, Mg, Co, Fe…) catalysts have therefore concentrated much attention as low-cost materials in the last decade.…”

Section: Introductionmentioning

confidence: 99%