Periodic DFT and HR-STEM Studies of Surface Structure and Morphology of Cobalt Spinel Nanocrystals. Retrieving 3D Shapes from 2D Images

Zasada, Filip; Piskorz, Witold; Stelmachowski, Paweł; Kotarba, Andrzej; Paul, Jean‐François; Płociński, Tomasz; Kurzydłowski, Krzysztof J.; Sojka, Zbigniew

doi:10.1021/jp200581s

Cited by 72 publications

(81 citation statements)

References 67 publications

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“…4 and 5. For the undoped spinels, FESEM images point out typical clusters of nanocrystals with the characteristic rhombicuboctahedral shapes, with the prevailing of (100) and (111) planes [47]. Specifically, the spinel prepared by precipitation comprises of the highest amount of the nanocrystals with dimensions below 20-30 nm, which is in agreement with the higher BET specific surface area displayed (31 m 2 g -1 , Table 1).…”

Section: Resultssupporting

confidence: 75%

The Effect of the Preparation Method of Pd-Doped Cobalt Spinel on the Catalytic Activity in Methane Oxidation Under Lean Fuel Conditions

et al. 2016

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In this work a series of cobalt spinel catalysts was synthesized by different methods and doped with 1 wt% of palladium via incipient wetness impregnation or solution combustion synthesis (SCS). Both undoped and Pd-doped spinels were characterized from the structural and surface point of view (XRD, XRF, lRS, BET, FESEM) and tested toward the oxidation of methane in lean conditions, in gas mixtures containing from 0.5 to 2 vol% of CH 4 . These methane concentrations are typical of processes involving combustion of CH 4 in lean conditions as the after-treatment of unconverted CH 4 in compressed natural gas-fed vehicle exhausts, or the treatment of fugitive CH 4 from leaks in coal mines. The temperature window for the catalytic activity of the undoped Co 3 O 4 materials spread from 350 to 600°C. The preparation method affected the catalytic activity of undoped Co 3 O 4 , with the best catalytic activity related to the spinel prepared by SCS employing urea. The addition of 1 wt% of Pd lowered the temperature window for the catalytic activity to the range of 250-500°C, with insignificant differences for the various preparation methods. The beneficial effect of Pd-doping was assigned to the enhancement of the reduction of cobalt in the oxide structure.

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Section: Resultssupporting

confidence: 75%

The Effect of the Preparation Method of Pd-Doped Cobalt Spinel on the Catalytic Activity in Methane Oxidation Under Lean Fuel Conditions

et al. 2016

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“…[21]. Thus, the most stable structure of the terminating (100) plane consists of four coordinationally unsaturated 5-fold Co 5c°, two recessed, fully coordinated 4-fold Co 4c T , and two protruding 2-fold Co 2c T .…”

Section: Determination Of the Hubbard Parameter Umentioning

confidence: 98%

“…There are two types of exposed oxygen ions: the 4-fold O 4c and 3-fold O 3c . Following [4,21], we modeled the (100) surface with 7 layer symmetrical and stoichiometric slabs shown in Fig. 2.…”

Section: Determination Of the Hubbard Parameter Umentioning

confidence: 99%

Water interaction with perfect and fluorine-doped Co3O4 (100) surface

et al. 2015

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“…The crystal habits are principally determined by relative energies of the exposed planes, and entropy terms normally do not affect this ordering [68]. The entropic and pV contributions to the free energies change slightly throughout the condensedphase species and in this type of calculation the entropic term is neglected [68][69][70][71][72][73]. Therefore, the difference between the Gibbs free energies can be approximated by the difference between the total energies from first-principles calculations [74][75][76].…”

Section: = -mentioning

confidence: 99%

Effects of surface stability on the morphological transformation of metals and metal oxides as investigated by first-principles calculations

et al. 2015

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Morphology is a key property of materials. Owing to their precise structure and morphology, crystals and nanocrystals provide excellent model systems for joint experimental and theoretical investigations into surface-related properties. Faceted polyhedral crystals and nanocrystals expose well-defined crystallographic planes depending on the synthesis method, which allow for thoughtful investigations into structure-reactivity relationships under practical conditions. This feature article introduces recent work, based on the combined use of experimental findings and first-principles calculations, to provide deeper knowledge of the electronic, structural, and energetic properties controlling the morphology and the transformation mechanisms of different metals and metal oxides: Ag, anatase TiO 2 , BaZrO 3 , and α-Ag 2 WO 4 . According to the Wulff theorem, the equilibrium shapes of these systems are obtained from the values of their respective surface energies. These investigations are useful to gain further understanding of how to achieve morphological control of complex three-dimensional crystals by tuning the ratio of the surface energy values of the different facets. This strategy allows the prediction of possible morphologies for a crystal and/or nanocrystal by controlling the relative values of surface energies.

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Periodic DFT and HR-STEM Studies of Surface Structure and Morphology of Cobalt Spinel Nanocrystals. Retrieving 3D Shapes from 2D Images

Cited by 72 publications

References 67 publications

The Effect of the Preparation Method of Pd-Doped Cobalt Spinel on the Catalytic Activity in Methane Oxidation Under Lean Fuel Conditions

The Effect of the Preparation Method of Pd-Doped Cobalt Spinel on the Catalytic Activity in Methane Oxidation Under Lean Fuel Conditions

Water interaction with perfect and fluorine-doped Co3O4 (100) surface

Effects of surface stability on the morphological transformation of metals and metal oxides as investigated by first-principles calculations

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