Density Functional Theory Study of Carboxylic Acids Adsorption and Enolization on Monoclinic Zirconia Surfaces

Ignatchenko, Alexey V.

doi:10.1021/jp203381h

Cited by 61 publications

(94 citation statements)

References 47 publications

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“…In the first case, the reduction of the carbonyl group at ethyl levulinate leads to the production of 4-hydroxy-ethyl valerate, which evolves through an intramolecular transesterification pathway towards γ-valerolactone (GVL), decreasing the selectivity of the process to the desired alcohol (42%). On the other hand, the low reaction rate observed for this substrate could be attributed to the presence of the carboxylate group in the ester moiety, which can lead to different molecular adsorption modes on the zirconium sites [32] either through the carbonyl or through the carboxylic acid group. In this way, the former is favorable to MPV conversion, whereas the latter is not, yielding only 24% of the desired alcohol product.…”

Section: Mpv Reduction Of Cyclohexanonementioning

confidence: 95%

Zr-SBA-15 Lewis Acid Catalyst: Activity in Meerwein Ponndorf Verley Reduction

et al. 2015

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Zr-SBA-15 Lewis acid catalyst has demonstrated an outstanding catalytic activity in the reduction of several carbonyl compounds by means of Meerwein Ponndorf Verley (MPV) reaction, using several secondary alcohols, and showing a very high selectivity towards the desired products. Special focus was addressed in the catalytic activity of Zr-SBA-15 material in the production of furfuryl alcohol from furfural, which is an important reaction for the lignocellulosic biomass valorization. In this transformation, both the reaction temperature and the i-PrOH:Furfural molar ratio exert a positive influence on the rate of the MPV transformation, with the influence of the former being much higher.i-propyl-furfuryl ether, a by-product resulting from the etherification of the target product with the sacrificing alcohol, is also found together with the main product. The production of this side-product is highly influenced by the reaction temperature, so that low temperatures and high sacrificing alcohol to substrate molar ratios have to be applied to keep its production at low levels.

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Section: Mpv Reduction Of Cyclohexanonementioning

confidence: 95%

Zr-SBA-15 Lewis Acid Catalyst: Activity in Meerwein Ponndorf Verley Reduction

et al. 2015

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“…The (011) and (101) surfaces have similar surface structure, featuring one five-coordinated, one sixcoordinated, and two seven-coordinated zirconium atoms in the topmost surface layers. The coordination numbers of the surface oxygen atoms are the same for each surface: one [16]; c Ref. [19] two-coordinated and four three-coordinated atoms per computational cell.…”

Section: Structures Of M-zro 2 Bulk and Surfacesmentioning

confidence: 99%

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Bazhenov

Honkala

2016

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Under the water-rich pre-treatment and/or reaction conditions, structure and chemistry of the monoclinic zirconia surfaces are strongly influenced by oxygen vacancies and incorporated water. Here, we report a combined first-principles and atomistic thermodynamics study on the structure and stability of selected surfaces of the monoclinic zirconia. Our results indicate that among the studied surfaces, the most stable (111) surface is the least vulnerable towards oxygen vacancies in contrast to the less stable (011) and (101) surfaces, where formation of oxygen vacancies is energetically more favorable. Furthermore, we present a vigorous, systematic screening of water incorporation onto the studied surfaces. We observe that the greatest stabilization of the surfaces is achieved when a part of the adsorbed water molecules is dissociated. Nevertheless, the importance of water dissociation for achieving the greatest stabilization is high for the less stable (011) and (101) surfaces, while completely hydrated (111) surface is stabilized equally regardless of the water dissociation state. Analysis of the constructed phase diagrams reveals that the (111) surface remains preferably clean and the (011) and (101) surfaces have dissociated water at low coverage under the reactive conditions of T = 600-900 K and p(H 2 O) < 1 bar. Upon temperature decrease and/or pressure increase, all studied surfaces gradually uptake water until fully hydrated. All in all, our findings complement and broaden the existing picture of the structure and stability of the monoclinic zirconia surfaces under the pre-treatment and/or reaction conditions, enabling rationalization of the potential roles of zirconia as a heterogeneous support and a catalyst component.

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“…The projector augmented wave method (PAW) [22] with the generalized gradient approximation (GGA) using the Perdew-Burke-Ernzerhof (PBE) functional [23] was used. In keeping with previous studies [16,24], a stable (111) plane with a (2 × 2) surface was utilized. Similar to the previous study [24], a supercell with 16 Zr and 32 O atoms was constructed.…”

Section: Computationalmentioning

confidence: 99%

“…In keeping with previous studies [16,24], a stable (111) plane with a (2 × 2) surface was utilized. Similar to the previous study [24], a supercell with 16 Zr and 32 O atoms was constructed. A vacuum space of 15Å and a 415 eV kinetic energy cut-off for a plane wave basis set was applied.…”

Section: Computationalmentioning

confidence: 99%

“…Adsorption energies (E ads ) were defined as E ads = E(adsorbate/ZrO 2 ) − E(ZrO 2 ) − E(adsorbate), where E(adsorbate/ZrO 2 ), E(ZrO 2 ), and E(adsorbate) are the calculated energies of a carboxylic acid on zirconia, a bare zirconia, and gas-phase carboxylic acid. The surface coverage was 25% [24]. To support the infrared spectroscopic measurements, frequencies were also calculated on the basis of the optimized structures.…”

Section: Computationalmentioning

confidence: 99%

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Preparation of Zirconium Oxide Powder Using Zirconium Carboxylate Precursors

Al-Hazmi

Choi

Apblett

2014

Advances in Physical Chemistry

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Zirconia was prepared at low temperatures (<450 ∘ C) using single several source precursors based on zirconium carboxylates where the R groups were systematically varied. The combination of density functional theory (DFT) calculations and extensive characterization of the precursors (i.e., X-ray diffraction, thermal gravimetric analysis, infrared spectroscopy, and scanning electron microscopy) indicated that the carboxylic acid complexes may link the zirconium metal with a cis bidentate configuration. Periodic DFT calculations were performed to examine the interaction between monoclinic ZrO 2 and propanoic acid. Dissociative adsorption takes place through the cis bidentate structure with an adsorption energy of −1.43 eV. Calculated vibrational frequencies using the optimized structure are in good agreement with experimental findings.

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Density Functional Theory Study of Carboxylic Acids Adsorption and Enolization on Monoclinic Zirconia Surfaces

Cited by 61 publications

References 47 publications

Zr-SBA-15 Lewis Acid Catalyst: Activity in Meerwein Ponndorf Verley Reduction

Zr-SBA-15 Lewis Acid Catalyst: Activity in Meerwein Ponndorf Verley Reduction

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Preparation of Zirconium Oxide Powder Using Zirconium Carboxylate Precursors

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