Design of a core–shell Pt–SiO2 catalyst in a reverse microemulsion system: Distinctive kinetics on CO oxidation at low temperature

AlMana, Noor; Phivilay, Somphonh P.; Laveille, Paco; Hedhili, Mohamed N.; Fornasiero, Paolo; Takanabe, Kazuhiro; Basset, Jean‐Marie

doi:10.1016/j.jcat.2016.06.002

Cited by 64 publications

(26 citation statements)

References 55 publications

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“…In one hand, these high-performance catalysts always require reducible oxides as supports, such as CeO 2 2 , FeO x 3 , MnO 2 4 , and Co 3 O 4 4 , due to their rich surface oxygen vacancy and the so-called “strong metal-support interaction” 6 – 8 . In another hand, the irreducible oxide (SiO 2 and Al 2 O 3 )-supported platinum catalysts with the advantages of commercial production, low cost, and extensive application frequently show poor catalytic activity in CO oxidation especially in low temperature because of the lack of surface activated oxygen and suitable active site 9 , 10 . Meanwhile, the aggregation of platinum species in SiO 2 -supported platinum catalysts frequently results in the deactivation of catalysts in CO oxidation.…”

Section: Introductionmentioning

confidence: 99%

Unique structure of active platinum-bismuth site for oxidation of carbon monoxide

Nan

et al. 2021

Nat Commun

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As the technology development, the future advanced combustion engines must be designed to perform at a low temperature. Thus, it is a great challenge to synthesize high active and stable catalysts to resolve exhaust below 100 °C. Here, we report that bismuth as a dopant is added to form platinum-bismuth cluster on silica for CO oxidation. The highly reducible oxygen species provided by surface metal-oxide (M-O) interface could be activated by CO at low temperature (~50 °C) with a high CO2 production rate of 487 μmolCO2·gPt−1·s−1 at 110 °C. Experiment data combined with density functional calculation (DFT) results demonstrate that Pt cluster with surface Pt−O−Bi structure is the active site for CO oxidation via providing moderate CO adsorption and activating CO molecules with electron transformation between platinum atom and carbon monoxide. These findings provide a unique and general approach towards design of potential excellent performance catalysts for redox reaction.

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Section: Introductionmentioning

confidence: 99%

Unique structure of active platinum-bismuth site for oxidation of carbon monoxide

Nan

et al. 2021

Nat Commun

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“…The catalytic oxidation of carbon monoxide (CO) is an important topic because of its numerous practical applications, including lowtemperature CO oxidation, preferential CO oxidation and automotive exhaust control [1][2][3]. Among the various proposed heterogeneous catalysts, mixed metal oxide catalysts containing Cu, Ce and Zr have attracted great interest in low-temperature CO oxidation because of their low cost and good sintering resistance, which are comparable or superior to those of noble metal catalysts [4,5].…”

Section: Introductionmentioning

confidence: 99%

Reaction mechanism and kinetics of CO oxidation over a CuO/Ce0.75Zr0.25O2-δ catalyst

Kang

Wei

Bin

et al. 2018

Applied Catalysis A: General

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A B S T R A C T The CuO/Ce 0.75 Zr 0.25 O 2δ and Ce 0.75 Zr 0.25 O δ catalysts were prepared by the sol-gel method, and Cu 0.07 Ce 0.75 Zr 0.25 O 2-δ was obtained by treating CuO/Ce 0.75 Zr 0.25 O 2δ with nitric acid to remove the well-dispersed CuO on the surface. Various characterizations were used to reveal the different active sites, such as surface-dispersed CuO and Cu-Ce-Zr-O δ solid solutions in CuO/Ce 0.75 Zr 0.25 O 2δ , Cu-Ce-Zr-O δ solid solutions in Cu 0.07 Ce 0.75 Zr 0.25 O 2-δ and Ce-Zr-O δ solid solutions in Ce 0.75 Zr 0.25 O δ . The Raman and O 2 -TPD results showed that the concentration of oxygen vacancies in Cu-Ce-Zr-O δ solid solutions was higher than that in Ce-Zr-O δ solid solutions. CO oxidation testing suggested that the catalytic activity decreases in the order of CuO/ Ce 0.75 Zr 0.25 O 2δ > Cu 0.07 Ce 0.75 Zr 0.25 O 2-δ > Ce 0.75 Zr 0.25 O δ .Combined with the in situ diffuse-reflectance Fourier transform (in situ DRIFT) results, the reaction sensitivity followed the order of CO linear chemisorption onto dispersed CuO x species (Mars-van Krevelen mechanism) > carbonate species onto a Cu-Ce-Zr-O δ solid solution (Langmuir-Hinshelwood mechanism) > carbonate species onto a Ce-Zr-O δ solid solution (Langmuir-Hinshelwood mechanism). Kinetic studies suggested that the power-law rate expressions and apparent activation energies were r = 6.02 × 10 −7 ×P CO 0.68 P O2 0.03 (53 ± 3 kJ/mol) for CuO/Ce 0.75 Zr 0.25 O 2δ , r = 5.86 × 10 −7 ×P CO 0.8 P O2 0.07 (105 ± 5 kJ/mol) for Cu 0.07 Ce 0.75 Zr 0.25 O 2-δ and r = 5.7 × 10 −7 ×P CO 0.75 P O2 0.12 (115 ± 6 kJ/mol) for Ce 0.75 Zr 0.25 O δ . The Mars-van Krevelen mechanism should be the crucial reaction pathway over CuO/Ce 0.75 Zr 0.25 O 2δ in CO interfacial reactions, although the Langmuir-Hinshelwood mechanism cannot be ignored, and the Langmuir-Hinshelwood mechanism mainly occurred over the Cu 0.07 Ce 0.75 Zr 0.25 O 2-δ and Ce 0.75 Zr 0.25 O δ catalysts, where the contribution from the Mars-van Krevelen mechanism was negligible due to the absence of surface CuO x species.

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“…Figure 2e illustrates TEM image of Fe 3 O 4 @SiO 2 nanoparticles, in which a spherical core/shell structure with just 12.2 nm single-core Fe 3 O 4 nanoparticles and a 14.9 nm shell thickness SiO 2 coating can be seen. Similarly, Lynch et al [52] reported that SiO 2 was deposited on Ni nanoparticles by the reverse microemulsion method to form [51] also synthesized Pt@SiO 2 core-shell nanoparticles via a water-in-oil reverse microemulsion. This kind of core-shell structured nanoparticles not only has the surface properties of SNs, but also can be multifunctional by combining other types of materials (such as quantum dots or magnetic nanoparticles [49]).…”

Section: Reverse Microemulsion Methodsmentioning

confidence: 98%

“…Reverse microemulsion method was used to synthesize silica-based nanocomposites with different structures, and these structures were of decisive significance for their properties and applications [42]. Moreover reverse microemulsion method was mainly used to synthesize mesoporous SNs [43][44][45], hollow SNs [45][46][47], and core-shell SNs [48][49][50][51][52] due to its convenient control on nanoparticle shape.…”

Section: Introductionmentioning

confidence: 99%

Emerging Applications of Silica Nanoparticles as Multifunctional Modifiers for High Performance Polyester Composites

et al. 2021

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Nano-modification of polyester has become a research hotspot due to the growing demand for high-performance polyester. As a functional carrier, silica nanoparticles show large potential in improving crystalline properties, enhancing strength of polyester, and fabricating fluorescent polyester. Herein, we briefly traced the latest literature on synthesis of silica modifiers and the resultant polyester nanocomposites and presented a review. Firstly, we investigated synthesis approaches of silica nanoparticles for modifying polyester including sol-gel and reverse microemulsion technology, and their surface modification methods such as grafting silane coupling agent or polymer. Then, we summarized processing technics of silica-polyester nanocomposites, like physical blending, sol-gel processes, and in situ polymerization. Finally, we explored the application of silica nanoparticles in improving crystalline, mechanical, and fluorescent properties of composite materials. We hope the work provides a guideline for the readers working in the fields of silica nanoparticles as well as modifying polyester.

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Design of a core–shell Pt–SiO2 catalyst in a reverse microemulsion system: Distinctive kinetics on CO oxidation at low temperature

Cited by 64 publications

References 55 publications

Unique structure of active platinum-bismuth site for oxidation of carbon monoxide

Unique structure of active platinum-bismuth site for oxidation of carbon monoxide

Reaction mechanism and kinetics of CO oxidation over a CuO/Ce0.75Zr0.25O2-δ catalyst

Emerging Applications of Silica Nanoparticles as Multifunctional Modifiers for High Performance Polyester Composites

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