The Characterization and Structure-Dependent Catalysis of Ceria with Well-Defined Facets

Mann, Amanda K. P.; Wu, Zili; Overbury, Steven H.

doi:10.1016/b978-0-12-801217-8.00003-7

Cited by 9 publications

(8 citation statements)

References 131 publications

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“…We interpreted the measurement of homogeneous Δ R 2 across the small molecule as an indication that the formation of the Pd sites on the surface of the ceria nanocubes resulted in a near-complete elimination of all oxygen vacancies from the support . As CeO 2 nanorods are known to contain more defects than CeO 2 of cubic morphology, , we ascribe the Δ R 2 dependency on θ observed here to the persistence of a significant number of oxygen vacancies on the Pd/CeO 2 nanorods. However, it should be noted that as the morphology affects both surface termination of the NP (i.e., (110) and (100) for the rod and cubic morphology, respectively) and acidic strength of Ce atoms, , additional structural factors might contribute to the persistence of anisotropy in the Δ R 2 data measured in the presence of Pd/CeO 2 nanorods.…”

Section: Results and Discussionmentioning

confidence: 65%

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO₂ Nanorods

Naik

Slowing

et al. 2020

ACS Appl. Nano Mater.

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Ceria-supported palladium (Pd/CeO2) has spawned significant attention in recent years due to its ability to catalyze selective hydrogenation of phenolic compounds to cyclohexanones and cyclohexanols at a mild temperature and pressure. However, the mechanistic basis by which ceria enhances catalytic conversion is still unclear. Here, we use the increase in the 13C transverse relaxation rate upon the addition of nanoparticles (NPs) (13C ΔR2) to investigate the adsorption of phenolic compounds on the surface of the Pd/CeO2 catalyst by solution NMR. We show that hydroxyphenols adsorb on the support more efficiently than underivatized phenol and methoxyphenols and that phenol derivatives with an oxygen atom at position 2 (i.e., 2-hydroxyphenol and 2-methoxyphenol) form very stable interactions with the Pd site of Pd/CeO2. An analysis of the kinetics of hydrogenation revealed that catalytic conversion is linearly correlated with the ability of the substrate to form interactions with the CeO2 support and is inhibited by the formation of stable substrate-Pd adducts. Our data suggest that CeO2-substrate interactions mediate phenol hydrogenation more efficiently than Pd-substrate interactions and explain the exceptional catalytic performance reported for Pd/CeO2.

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Section: Results and Discussionmentioning

confidence: 65%

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO₂ Nanorods

Naik

Slowing

et al. 2020

ACS Appl. Nano Mater.

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“…Apart from its well-established application in three-way catalysis (TWC) [2], ceria is looming as a catalyst component for a wide range of catalytic applications [3] such as soot oxidation [4,5], NH 3 -SCR reactions [6,7], remediation of volatile organic compounds (VOCs) [8], removal of CO 2 , SO 2 and NOx gases [9], hydrogen purification and production processes [10], conversion of CO 2 [11], wet air oxidation [12] reforming of hydrocarbons and so on [1]. The shape and size modification, surface/face reconstruction, and faceting of ceria at the nanoscale level can offer an important tool to govern activity and stability in these reactions [13][14][15][16][17][18]. Furthermore, strong interaction between noble metals and ceria leads to their higher dispersion, electronic modifications and enhanced catalytic activity [19].…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy as a powerful tool to characterize ceria-based catalysts

2021

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A review. CeO 2 is widely used and investigated as an oxide catalyst or support due to its unique redox property of oxygen storage and release. In this paper, the different opportunities offered by Raman spectroscopy for advanced characterization of ceria-based catalysts are reviewed: spectral modifications induced by nanocrystallinity, defects, doping and reduction, identification of supported molecular species, isolated atoms and nanoclusters, characterization of surface modes, hydroxyl groups, reaction intermediates such as peroxo and superoxo species. Finally, in situ/operando studies for environmental catalysis are summarized illustrating Raman spectroscopy as a powerful tool to characterize ceria-based catalysts.

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“…In order to obtain insights into the structure dependence in chemical reactivity, we and others have explored surface chemistry on oriented single crystal films of CeO 2 [8,9] and catalytic reactions on shape-controlled CeO2 nanoparticles [7,10,11]. Guided by such experimental studies on structurally well-defined surfaces it is of complimentary value to use computational methods to probe reaction pathways and surface molecular interaction [12,13].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen and methoxy coadsorption in the computation of the catalytic conversion of methanol on the ceria (111) surface

Beste

Overbury

2016

Surface Science

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Methanol decomposition to formaldehyde catalyzed by the ceria (111) surface has been investigated using the DFT+U method. Our results rationalize experimental temperature programmed desorption experiments on the fully oxidized surface. Particular attention has been paid to the model correctness of methoxy with coadsorbed hydrogen on the surface. This issue has been raised by the experimental observation of water desorption at low temperature removing hydrogen from the system. Our investigation also includes hydrogen diffusion as a means of hydrogen removal. We show that the CH 3 O − /H + ion pair remains at large separation, rendering the coadsorbed model as appropriate in contrast to a neutral isolated methoxy, for which the dehydrogenation barrier becomes negligible. We find that the presence of methoxy reduces the reaction energy for water formation considerably. In

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The Characterization and Structure-Dependent Catalysis of Ceria with Well-Defined Facets

Cited by 9 publications

References 131 publications

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO₂ Nanorods

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO₂ Nanorods

Raman spectroscopy as a powerful tool to characterize ceria-based catalysts

Hydrogen and methoxy coadsorption in the computation of the catalytic conversion of methanol on the ceria (111) surface

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The Characterization and Structure-Dependent Catalysis of Ceria with Well-Defined Facets

Cited by 9 publications

References 131 publications

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO2 Nanorods

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO2 Nanorods

Raman spectroscopy as a powerful tool to characterize ceria-based catalysts

Hydrogen and methoxy coadsorption in the computation of the catalytic conversion of methanol on the ceria (111) surface

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Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO₂ Nanorods

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO₂ Nanorods