Growth, characterization and interfacial reaction of magnetron sputtered Pt/CeO2 thin films on Si and Si3N4 substrates

Anandan, C.; Bera, Parthasarathi

doi:10.1002/sia.5774

Cited by 12 publications

(2 citation statements)

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“…These ionic species are experimentally observed in Pt/CeO 2 thin films prepared with magnetron sputtering deposition. 16,33 Our model of Pt− CeO 2 (111) solid solution was a (3 × 3) supercell in which one surface Ce ion is substituted by a Pt atom (Figure 1b). The analyses of DOS and PDOS of the Pt−CeO 2 (111) solid solution (Figure S1) show that the Ce(f) states are above the Fermi level, confirming that there is no surface reduction induced by Pt doping and that the Pt species are in 4+ oxidation state.…”

Section: Resultsmentioning

confidence: 99%

Probing the Reactivity of Pt/Ceria Nanocatalysts toward Methanol Oxidation: From Ionic Single-Atom Sites to Metallic Nanoparticles

2018

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Single-atom catalysts represent the ultimate extreme in heterogeneous catalysis for the maximum dispersion of mononuclear catalytic metal particles on supporting surfaces. Ultralow Pt loading has been achieved on nanostructured ceria surfaces that allow for stabilizing metallic and ionic Pt sites that are anchored at surface defects. Here, we assess the chemical reactivity of these different Pt species, which are experimentally known to coexist on Pt−ceria nanocatalysts, by taking methanol oxidation as a chemical probe. Our density functional theory calculations demonstrate that Pt 2+ and Pt 4+ single-ion species do not promote methanol oxidation by themselves. Instead, metallic sites of supported sub-nanometer Pt particles are always required to promote the oxidation reaction. Our finding generalizes the conclusions of recent photoemission experiments in the context of H 2 oxidation by ceria/Pt nanocatalysts. Moreover, the simulations predict that surface hydroxide groups may act as cocatalyst for the direct methanol oxidation to formaldehyde, thus proposing a viable strategy for catalyst design.

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Section: Resultsmentioning

confidence: 99%

Probing the Reactivity of Pt/Ceria Nanocatalysts toward Methanol Oxidation: From Ionic Single-Atom Sites to Metallic Nanoparticles

2018

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“…The Pt 4f spectra were deconvoluted into two pairs for all samples. The peaks at 72.65-72.68 eV and 75.98-76.08 eV are attributed to Pt 2+ species, and the peaks at 74.47-74.62 eV and 77.80-77.94 eV are associated with Pt 4+ species [40]. The ratio of Pt 4+ in the total Pt species was calculated based on the corresponding peak areas and listed in Table 3.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Steam Treatment Promotion on the Performance of Pt/CeO2 Three-Way Catalysts for Emission Control of Natural Gas-Fueled Vehicles

Liu,

Shao,

Ren

et al. 2023

Catalysts

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Three-way catalyst (TWC) is the mainstream technology for stoichiometric natural gas vehicle gas emission purification to meet the China VI emission standard for heavy-duty vehicles. Due to the high price of Pd-Rh TWC widely used at present, it is of great significance to develop cheaper Pt-only catalysts as substitutes. However, there are few studies on Pt-only TWC, especially for natural gas vehicles. It remains a formidable challenge to develop Pt-only TWC with excellent activity and stability. In this study, we significantly improved the catalytic performance of Pt/CeO2 TWC through thermal treatment, especially steam treatment at 800 °C, and used XRD, TEM, H2-TPR, and XPS techniques to investigate how Pt/CeO2 can be activated via these treatments. Our results suggested that after these treatments, CeO2 crystallites sintered slightly, while platinum particles remained highly dispersed. Moreover, these treatments also weakened the Pt-CeO2 interaction, promoted the formation of oxygen vacancies in CeO2 support, and generated a new type of active surface oxygen in the vicinity of Ptδ+, thus improving the activity of the catalyst. After 800 °C steam treatment, the T50 of CH4 and NO decreased by 31 and 36 °C, respectively. The results obtained in this study provide implications for the synthesis of efficient Pt-based catalysts.

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Nanoporous Platinum Doped Cerium Oxides Thin Films Grown on Silicon Substrates: Ionic Platinum Localization and Stability

Simon

Zanfoni

Avril

et al. 2016

Adv Materials Inter

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In this study, the characterization of nanostructured Pt‐doped CeO2 films with low platinum content and porous structure is reported, deposited on silicon substrate by direct liquid injection chemical vapor deposition. The platinum localization and concentration in the nanocomposite are determined by scanning transmission electron microscopy associated with energy dispersive X‐ray spectroscopy. Films are made of ≈3 nm diameter CeO2 particles and platinum is homogeneously dispersed through the layers. X‐ray photoelectron spectroscopy (XPS) also shows that platinum is mainly in an ionic Pt2+ state. After diffusion through the preformed porous structure of ceria films, the platinum precursor decomposes at the surface of each ceria particle forming the films, producing a homogeneous platinum‐doped CeO2 nanocomposite. This result is supported by synchrotron radiation XPS experiment, where the measured relative Pt concentration demonstrates that platinum is decomposed only at the surface of ceria particles. Finally, when the saturation of Pt2+ sites at the surface of ceria particles is reached, metallic nanoclusters are formed from platinum excess.

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Growth, characterization and interfacial reaction of magnetron sputtered Pt/CeO₂ thin films on Si and Si₃N₄ substrates

Cited by 12 publications

References 50 publications

Probing the Reactivity of Pt/Ceria Nanocatalysts toward Methanol Oxidation: From Ionic Single-Atom Sites to Metallic Nanoparticles

Probing the Reactivity of Pt/Ceria Nanocatalysts toward Methanol Oxidation: From Ionic Single-Atom Sites to Metallic Nanoparticles

Steam Treatment Promotion on the Performance of Pt/CeO2 Three-Way Catalysts for Emission Control of Natural Gas-Fueled Vehicles

Nanoporous Platinum Doped Cerium Oxides Thin Films Grown on Silicon Substrates: Ionic Platinum Localization and Stability

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