Nanoscale (111) faceted rock-salt metal oxides in catalysis

Cadigan, Chris; Corpuz, April; Lin, Feng; Caskey, Christopher M.; Finch, Kenneth B.; Wang, Xue; Richards, Ryan M.

doi:10.1039/c2cy20373a

Cited by 62 publications

(66 citation statements)

References 172 publications

(323 reference statements)

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“…30 According to our recent experimental results, 3 the carbonate species on the (110) planes disappear at a temperature lower than the desorption temperature predicted with atomistic modelling. That phenomenon was assigned to the disappearance of the (110) planes themselves at a temperature temp between 673K and 873 K.…”

Section: Correlation With Catalytic Datamentioning

confidence: 78%

Influence of natural adsorbates of magnesium oxide on its reactivity in basic catalysis

Petitjean

Costentin

Guesmi

et al. 2013

Phys. Chem. Chem. Phys.

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, et al.. Influence of natural adsorbates of magnesium oxide on its reactivity in basic catalysis. Physical Chemistry Chemical Physics, Royal Society of Chemistry, 2013, 15 (45), pp.19870-19878 isomerization and one alcohol conversion (hept-1-ene isomerization and 2-methyl-3-butyn-2-ol conversion). Catalysis experiments showed that carbon dioxide adsorption poisons the catalyst surface and the DRIFT-DFT combination showed that the nature of active sites in the two reactions differs. On the reverse, partial hydroxylation of the surface enhances activity for both reactions. Interestingly hept-1-ene isomerization gives a volcano curve for the conversion as a function of hydroxyl coverage.Calculations of the electronic structure of magnesium oxide surface show that neither Lewis basicity nor Brønstedt basicity of the surface defects (steps for example) are enhanced by hydroxylation.Meanwhile CO 2 adsorption followed by IR spectroscopy shows that (110) and (111) unstable planes are strongly basic and are stabilized by partial surface hydroxylation. That result could explain the volcano curve obtained for the evolution of alkene isomerisation as a function of hydroxyl coverage.present address :

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Section: Correlation With Catalytic Datamentioning

confidence: 78%

Influence of natural adsorbates of magnesium oxide on its reactivity in basic catalysis

Petitjean

Costentin

Guesmi

et al. 2013

Phys. Chem. Chem. Phys.

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“…4 In this respect MgO dissolution and transformation into Mg(OH) 2 brucite represents a prominent system for related investigations since respective insights are also of broader interests for very different fields like the application of refractory materials 9 , passive water treatment 10 , geochemistry and -last but not least -the design of nanomaterials and catalysts. [11][12][13][14][15][16] MgO dissolution processes on well-defined single crystal surfaces have been studied experimentally [17][18][19] and theoretically. [20][21][22] A recent surface science study on the interaction of water with MgO(001) films revealed the emergence of disordered hydroxide surface layers that inhibit the dissolution process at higher pH values.…”

Section: Introductionmentioning

confidence: 99%

Size Effects in MgO Cube Dissolution

et al. 2015

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Stability parameters and dissolution behavior of engineered nanomaterials in aqueous systems are critical to assess their functionality and fate under environmental conditions. Using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, we investigated the stability of cubic MgO particles in water. MgO dissolution proceeding via water dissociation at the oxide surface, disintegration of Mg(2+)-O(2-) surface elements, and their subsequent solvation ultimately leads to precipitation of Mg(OH)2 nanosheets. At a pH ≥ 10, MgO nanocubes with a size distribution below 10 nm quantitatively dissolve within few minutes and convert into Mg(OH)2 nanosheets. This effect is different from MgO cubes originating from magnesium combustion in air. With a size distribution in the range 10 nm ≤ d ≤ 1000 nm they dissolve with a significantly smaller dissolution rate in water. On these particles water induced etching generates (110) faces which, above a certain face area, dissolve at a rate equal to that of (100) planes.1 The delayed solubility of microcrystalline MgO is attributed to surface hydroxide induced self-inhibition effects occurring at the (100) and (110) microplanes. The present work underlines the importance of morphology evolution and surface faceting of engineered nanomaterials particles during their dissolution.

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“…C hemical evolution and structural transformations at the surface of a material directly influence characteristics relevant to a wide range of prominent applications including heterogeneous catalysis [1][2][3] and energy storage 4,5 . Structural and/or chemical rearrangements at surfaces determine the way a material interacts with its surrounding environment, thus controlling the functionalities of the material [6][7][8][9][10] .…”

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confidence: 99%

Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries

et al. 2014

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The present study sheds light on the long-standing challenges associated with high-voltage operation of LiNi x Mn x Co 1 À 2x O 2 cathode materials for lithium-ion batteries. Using correlated ensemble-averaged high-throughput X-ray absorption spectroscopy and spatially resolved electron microscopy and spectroscopy, here we report structural reconstruction (formation of a surface reduced layer, R 3m to Fm 3m transition) and chemical evolution (formation of a surface reaction layer) at the surface of LiNi x Mn x Co 1 À 2x O 2 particles. These are primarily responsible for the prevailing capacity fading and impedance buildup under high-voltage cycling conditions, as well as the first-cycle coulombic inefficiency. It was found that the surface reconstruction exhibits a strong anisotropic characteristic, which predominantly occurs along lithium diffusion channels. Furthermore, the surface reaction layer is composed of lithium fluoride embedded in a complex organic matrix. This work sets a refined example for the study of surface reconstruction and chemical evolution in battery materials using combined diagnostic tools at complementary length scales. C hemical evolution and structural transformations at the surface of a material directly influence characteristics relevant to a wide range of prominent applications including heterogeneous catalysis 1-3 and energy storage 4,5 . Structural and/or chemical rearrangements at surfaces determine the way a material interacts with its surrounding environment, thus controlling the functionalities of the material [6][7][8][9][10] . Specifically, the surfaces of lithium-ion battery electrodes evolve simultaneously with charge-discharge cycling (that is, in situ surface reconstruction and formation of a surface reaction layer (SRL)) that can lead to deterioration of performance 4,5,11 . An improved understanding of in situ surface reconstruction phenomena imparts knowledge not only for understanding degradation mechanisms for battery electrodes but also to provide insights into the surface functionalization for enhanced cyclability 12,13 .The investigation of in situ surface reconstruction of layered cathode materials, such as stoichiometric LiNi x Mn x Co 1 À 2x O 2 (that is, NMC), lithium-rich Li(Li y Ni x À y Mn x Co 1 À 2x )O 2 , lithium-rich/ manganese-rich (composite layered-layered) xLi 2 MnO 3 Á (1 À x) LiMO 2 (M ¼ Mn, Ni, Co, and so on) materials, is technologically significant as they represent a group of materials with the potential to improve energy densities and reduce costs for plug-in hybrid electric vehicles and electric vehicles [14][15][16][17] . Practical implementation of some of these materials is thwarted by their high first-cycle coulombic inefficiencies [17][18][19][20] , capacity fading 18,21 and voltage instability [20][21][22] , especially during high-voltage operation. Specifically, high-voltage charge capacities achieved in lithiumrich/manganese-rich layered cathodes are directly associated with various irreversible electrochemical processes including o...

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Nanoscale (111) faceted rock-salt metal oxides in catalysis

Cited by 62 publications

References 172 publications

Influence of natural adsorbates of magnesium oxide on its reactivity in basic catalysis

Influence of natural adsorbates of magnesium oxide on its reactivity in basic catalysis

Size Effects in MgO Cube Dissolution

Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries

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