Synergistic effect between CeO2 nanowires and gold NPs over the activity and selectivity in the oxidation of thioanisole

Rosado, Taissa F.; Teixeira, Moisés P.; Moraes, Leonardo C.; Silva, Leonardo A. da; Pontes-Silva, Augusto V.; Taylor, Jason G.; Freitas, Isabel C. de; Oliveira, Daniela C. de; Gardener, Jules; Solórzano, Guillermo; Alves, Tiago Vinicius; Venâncio, Mateus F.; Silva, Maria I. P. da; Brocchi, E. A.; Fajardo, Humberto V.; Silva, Anderson G. M. da

doi:10.1016/j.apcata.2021.118010

Cited by 17 publications

(5 citation statements)

References 53 publications

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“…Due to metal-support interactions, the deposition of noble metals over MnO 2 has been an efficient strategy for improving electrocatalytic performances [ 21 , 22 ]. Moreover, metal NPs may interact/cooperate with metal oxides to facilitate catalytic reactions, in which the reducibility of the inorganic matrix usually represents a key element over the detected catalytic activities [ 23 , 24 ]. To further provide in-depth information into these features, the ultrasmall Ir NPs decorated onto MnO 2 nanowires by hydrogen temperature-programmed reduction was investigated, as shown in Figure 3 B.…”

Section: Resultsmentioning

confidence: 99%

“…Before the H 2 -TPR measurements, the samples were heat-treated at 200 °C for 30 min under N 2 flow to remove moisture adsorbed. After cooling to room temperature, the reduction gas of 8.0% H 2 /N 2 at a flow rate of 20 mL/min was introduced, and the temperature was raised linearly to 950 °C at a heating rate of 10 [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] Using Spectro Arcos equipment, the Ir atomic percentages were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). For ICP-OES, the MnO 2 powder samples were fixed on stainless steel holders using double adhesive carbon tape.…”

Section: Methodsmentioning

confidence: 99%

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MnO2-Ir Nanowires: Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

et al. 2022

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Although clean energy generation utilizing the Oxygen Reduction Reaction (ORR) can be considered a promising strategy, this approach remains challenging by the dependence on high loadings of noble metals, mainly Platinum (Pt). Therefore, efforts have been directed to develop new and efficient electrocatalysts that could decrease the Pt content (e.g., by nanotechnology tools or alloying) or replace them completely in these systems. The present investigation shows that high catalytic activity can be reached towards the ORR by employing 1.8 ± 0.7 nm Ir nanoparticles (NPs) deposited onto MnO2 nanowires surface under low Ir loadings (1.2 wt.%). Interestingly, we observed that the MnO2-Ir nanohybrid presented high catalytic activity for the ORR close to commercial Pt/C (20.0 wt.% of Pt), indicating that it could obtain efficient performance using a simple synthetic procedure. The MnO2-Ir electrocatalyst also showed improved stability relative to commercial Pt/C, in which only a slight activity loss was observed after 50 reaction cycles. Considering our findings, the superior performance delivered by the MnO2-Ir nanohybrid may be related to (i) the significant concentration of reduced Mn3+ species, leading to increased concentration of oxygen vacancies at its surface; (ii) the presence of strong metal-support interactions (SMSI), in which the electronic effect between MnOx and Ir may enhance the ORR process; and (iii) the unique structure comprised by Ir ultrasmall sizes at the nanowire surface that enable the exposure of high energy surface/facets, high surface-to-volume ratios, and their uniform dispersion.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

MnO2-Ir Nanowires: Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

et al. 2022

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“…Predicting the thermodynamic stability of Ce 1−x Tm x O 2 (Tm = Co, Ni) included looking at a number of factors, including specific heat (C V ), temperature-and pressure-dependent Gibbs free energy (G), and thermal expansion (α). The Gibbs2 algorithm is used to compute thermodynamic parameters using the quasi-harmonic Debye approximation [40].…”

Section: Thermodynamic Propertiesmentioning

confidence: 99%

First-principles quantum analysis of structural, optoelectronic, and thermophysical properties of Co/Ni doped ceria Ce_1−xTm_xO₂ (Tm=Co, Ni) for solar cell applications

Mirza,

Abbas,

Parveen

et al. 2024

Phys. Scr.

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The properties of CeO2 thin films, such as their memory store capabilities, visual transparency, chemical and thermal durability, adjustable energy band topologies, and high oxygen storage capacity have captured the attention of scientists. The energy band dispersions for Ce1-xTmxO2 (Tm= Co, Ni; x= 12.5%) are calculated to get insight into the characteristics of the materials under investigation. The anticipated energy bandgaps for Ce1-xCoxO2 and Ce1-xNixO2 are 2.6 and 2.7 eV, respectively, in the spin ↑ channel . However, both compounds show metallic character in in spin ↓ channel. The phenomena of photon absorption/dispersion by the host materials can be elucidated using dielectric function ε(ω) of Ce1-xTmxO2 (Tm= Co, Ni; x= 12.5%). Significant photon absorption can be noted in UV and IR regions for Ce1-xTmxO2 (Tm= Co, Ni; x= 12.5%) in spin ↑ and spin ↓ channels, respectively. Ce1-xTmxO2 (Tm= Co, Ni; x= 12.5%) exhibits a minimal photon reflection, approximately 15%. Ce1-xNixO2 shows excellent thermoelectric characteristics as its ZT value is high (1.8 at 1000K) compared to Ce1-xCoxO2. Based on their thermodynamic properties, Ce1-xTmxO2 (Tm= Co, Ni; x= 12.5%) are thermodynamically stable compounds.

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“…More specifically, oxygen vacancies are a dominant type of defect in many metal oxides and have been widely investigated by theoretical calculations and experimental characterizations . Indeed, it has been found that oxygen vacancies are important as active sites for heterogeneous catalysis, which strongly affect their activity. − Hydrogen spillover from noble-metal NPs (Pt, Pd, Ru, or Rh) to reducible metal oxides is also important for various reduction reactions. , This effect has also proved to have an important role in ammonia synthesis. , Generally, the H 2 molecules are first chemically adsorbed and dissociated into atomic species by metal nanoparticles; then, they migrate to supports, providing active species for catalytic reactions. , If the support used is a reducible oxide such as TiO 2 , hydrogen spillover can significantly enhance their reducibility. The combination of Ru NPs and TiO 2 may be a promising strategy for this type of application due to the possibility of tuning their high thermal resistance, presence of oxygen vacancies, facilitated hydrogen spillover, and high catalytically active phase.…”

Section: Introductionmentioning

confidence: 99%

Correlating O-Vacancy and Hydrogen Spillover with Activity and Selectivity in Furfural Hydrogenation Using Nanocatalysts Comprised of Ru Nanoparticles Supported on TiO₂–SiO₂

Almeida

Bazan

Gastelois

et al. 2023

ACS Appl. Nano Mater.

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The nanoengineering of efficient and stable nanocatalysts is highly desired for sustainable biomass valorization toward the selective hydrogenation of furfural. The interaction of supports with metallic nanoparticles and oxygen vacancies has a significant role in the catalytic activity of oxide nanocatalysts. Here, by combining density functional theory (DFT) calculations and catalytic experimental data, we demonstrated that the presence of TiO 2 in Ru−SiO 2 catalysts might allow an association between oxygen vacancies and the hydrogen spillover effect. Specifically, Ru−TiO 2 −SiO 2 and Ru−SiO 2 nanocatalysts displayed improved activities and selectivities toward the reaction mentioned above. The nanomaterials were prepared by a simple, versatile, and single-step modified sol− gel process build upon two different stabilizing agents (P123 and CTAB), which afforded entirely covered surfaces of TiO 2 −SiO 2 and SiO 2 supports with uniform small Ru nanoparticles generated in situ. The Ru-TSdc nanocatalyst displayed several interesting promising nanoscale features for hydrogenation of furfural: (i) uniform distribution of Ru, Ti, and Si elements over the entire catalyst surface, (ii) deposition of small Ru nanoparticles with no significant particle agglomeration, (iii) facilitated hydrogen spillover from Ru NPs to the TiO 2 support, and (iv) a significant amount of oxygen vacancies at the nanoparticle surface. For these reasons, the Ru-TSdc sample afforded the optimal performance toward the selective hydrogenation of furfural (up to 99% of selectivity), maintaining good conversions in certain reaction conditions. This work demonstrates how the catalytic activity of metallic nanoparticles could be improved by the structural addition of a reducible oxide, leading to more efficient inorganic supports and for preparing nanocatalysts.

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Synergistic effect between CeO2 nanowires and gold NPs over the activity and selectivity in the oxidation of thioanisole

Cited by 17 publications

References 53 publications

MnO2-Ir Nanowires: Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

MnO2-Ir Nanowires: Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

First-principles quantum analysis of structural, optoelectronic, and thermophysical properties of Co/Ni doped ceria Ce_1−xTm_xO₂ (Tm=Co, Ni) for solar cell applications

Correlating O-Vacancy and Hydrogen Spillover with Activity and Selectivity in Furfural Hydrogenation Using Nanocatalysts Comprised of Ru Nanoparticles Supported on TiO₂–SiO₂

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Synergistic effect between CeO2 nanowires and gold NPs over the activity and selectivity in the oxidation of thioanisole

Cited by 17 publications

References 53 publications

MnO2-Ir Nanowires: Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

MnO2-Ir Nanowires: Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

First-principles quantum analysis of structural, optoelectronic, and thermophysical properties of Co/Ni doped ceria Ce1−xTmxO2 (Tm=Co, Ni) for solar cell applications

Correlating O-Vacancy and Hydrogen Spillover with Activity and Selectivity in Furfural Hydrogenation Using Nanocatalysts Comprised of Ru Nanoparticles Supported on TiO2–SiO2

Contact Info

Product

Resources

About

First-principles quantum analysis of structural, optoelectronic, and thermophysical properties of Co/Ni doped ceria Ce_1−xTm_xO₂ (Tm=Co, Ni) for solar cell applications

Correlating O-Vacancy and Hydrogen Spillover with Activity and Selectivity in Furfural Hydrogenation Using Nanocatalysts Comprised of Ru Nanoparticles Supported on TiO₂–SiO₂