Magnetic properties of Ni(II)–Mn(III) LDHs

Giovannelli, Fabien; Zaghrioui, Mustapha; Autret-Lambert, Cécile; Delorme, Fabian; Seron, Alain; Chartier, T.; Pignon, B.

doi:10.1016/j.matchemphys.2012.07.057

Cited by 25 publications

(14 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The XRD pattern of the Ni-Mn LDH nanosheets shows the diffraction peaks at 2q values of 11.3, 22.6, 34.2, and 38.78 (Figure 4 A), which can be indexed to (003), (006), (012), and (015) reflections of the hydrotalcite-like phase, respectively. [24][25][26] The interlamellar spacing measured by XRD was 0.78 nm, which was in good agreement with the result from the HRTEM analysis. We did not observe any characteristic peaks of metal oxides such as Mn 3 O 4 or NiO, confirming the formation of Ni-Mn LDH structures.…”

Section: Resultssupporting

confidence: 87%

Reverse Micelle Synthesis of Colloidal Nickel–Manganese Layered Double Hydroxide Nanosheets and Their Pseudocapacitive Properties

Sim

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

Colloidal nanosheets of nickel-manganese layered double hydroxides (LDHs) have been synthesized in high yields through a facile reverse micelle method with xylene as an oil phase and oleylamine as a surfactant. Electron microscopy studies of the product revealed the formation of colloidal nanoplatelets with sizes of 50-150 nm, and X-ray diffraction, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy studies showed that the Ni-Mn LDH nanosheets had a hydrotalcite-like structure with a formula of [Ni3 Mn(OH)8 ](Cl(-) )⋅n H2 O. We found that the presence of both Ni and Mn precursors was required for the growth of Ni-Mn LDH nanosheets. As pseudocapacitors, the Ni-Mn LDH nanosheets exhibited much higher specific capacitance than unitary nickel hydroxides and manganese oxides.

show abstract

Section: Resultssupporting

confidence: 87%

Reverse Micelle Synthesis of Colloidal Nickel–Manganese Layered Double Hydroxide Nanosheets and Their Pseudocapacitive Properties

Sim

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…The calculations indicate that Fe 4+ is also high spin, which has not been resolved experimentally, but may arise from the constraints and environment imposed by the extended lattice. Moreover, Mn 3+ , which is isoelectronic to Fe 4+ , in the analogous NiMn layered double hydroxide has been found to be high spin (40). The computed magnetizations and corresponding oxidation states for each metal site in the unit cell of the periodic system are depicted in Fig.…”

Section: Resultsmentioning

confidence: 98%

Characterization of NiFe oxyhydroxide electrocatalysts by integrated electronic structure calculations and spectroelectrochemistry

Goldsmith

Harshan

Gerken

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

203

161

View full text Add to dashboard Cite

NiFe oxyhydroxide materials are highly active electrocatalysts for the oxygen evolution reaction (OER), an important process for carbon-neutral energy storage. Recent spectroscopic and computational studies increasingly support iron as the site of catalytic activity but differ with respect to the relevant iron redox state. A combination of hybrid periodic density functional theory calculations and spectroelectrochemical experiments elucidate the electronic structure and redox thermodynamics of Ni-only and mixed NiFe oxyhydroxide thin-film electrocatalysts. The UV/visible light absorbance of the Ni-only catalyst depends on the applied potential as metal ions in the film are oxidized before the onset of OER activity. In contrast, absorbance changes are negligible in a 25% Fe-doped catalyst up to the onset of OER activity. First-principles calculations of proton-coupled redox potentials and magnetizations reveal that the Ni-only system features oxidation of Ni 2+ to Ni 3+ , followed by oxidation to a mixed Ni 3+/4+ state at a potential coincident with the onset of OER activity. Calculations on the 25% Fedoped system show the catalyst is redox inert before the onset of catalysis, which coincides with the formation of Fe 4+ and mixed Ni oxidation states. The calculations indicate that introduction of Fe dopants changes the character of the conduction band minimum from Ni-oxide in the Ni-only to predominantly Fe-oxide in the NiFe electrocatalyst. These findings provide a unified experimental and theoretical description of the electrochemical and optical properties of Ni and NiFe oxyhydroxide electrocatalysts and serve as an important benchmark for computational characterization of mixedmetal oxidation states in heterogeneous catalysts.NiFe oxyhydroxide | oxygen evolution reaction | electrocatalysis | spectroelectrochemistry | density functional theory T he photoelectrochemical conversion of water into O 2 and H 2 is a major focus of energy storage and conversion efforts (1-4), with significant attention directed toward development of efficient catalysts for water oxidation and reduction. Such catalysts should operate at low overpotential, exhibit high selectivity, and be composed of earth-abundant materials. Commercial electrolyzers typically use transition-metal-oxide electrocatalysts for the oxygen evolution reaction (OER) (5, 6), and nickel, nickel-iron, and other mixed-metal oxides are especially effective under alkaline conditions (7,8). Despite the importance and potential future impact of these materials, many features of their catalytic mechanism are poorly understood.Nickel oxyhydroxide has long been associated with OER electrocatalysis (9, 10); however, much of the activity in this material has been shown to arise from the presence of Fe impurities (7, 11). This conclusion complements extensive independent studies demonstrating the effectiveness of NiFebased oxide and oxyhydroxide materials as OER electrocatalysts (12-14), including a survey of nearly 3,500 mixed-metal-oxide compositions, which drew attentio...

show abstract

“…Luminescence properties of LDHs with M 3+ partly substituted by rare earth cation [22][23][24] have recently been reported. The layered double hydroxides, in which at least one of the metal cations is magnetic: Co 2+ , Ni 2+ , Mn 3+ , Cr 3+ or Fe 3+ , were studied [25][26][27][28][29][30][31][32][33]. Onset of spontaneous magnetization and a peak of magnetic susceptibility were observed in those LDHs at temperatures of a few K. The highest T C of 26 K was reported for Ni 4 Mn-CO 3 LDH [28].…”

Section: Introductionmentioning

confidence: 99%

High-Power Ultrasonic Synthesis and Magnetic-Field-Assisted Arrangement of Nanosized Crystallites of Cobalt-Containing Layered Double Hydroxides

et al. 2019

View full text Add to dashboard Cite

High-quality stoichiometric Co2Al–NO3 and Co2Al–CO3 layered double hydroxides (LDHs) have been obtained by precipitation followed by anion exchange, both high-power-sonication assisted. Application of high-power ultrasound has been demonstrated to result in a considerable acceleration of the crystallization process and the anion-exchange reaction. Two independent approaches were used to form bulk and 2-D samples of Co2Al–NO3 with the oriented crystallites, namely uniaxial pressing of deposits from sonicated LDH slurries and magnetic field-assisted arrangement of LDH crystallites precipitating on glass substrates. A convenient way of preparation of semi-transparent compacts with relatively big blocks of oriented crystallites have been demonstrated. Thin dense transparent films of highly-ordered crystallites of Co2Al–NO3 LDH have been produced and characterized.

show abstract

Magnetic properties of Ni(II)–Mn(III) LDHs

Cited by 25 publications

References 32 publications

Reverse Micelle Synthesis of Colloidal Nickel–Manganese Layered Double Hydroxide Nanosheets and Their Pseudocapacitive Properties

Reverse Micelle Synthesis of Colloidal Nickel–Manganese Layered Double Hydroxide Nanosheets and Their Pseudocapacitive Properties

Characterization of NiFe oxyhydroxide electrocatalysts by integrated electronic structure calculations and spectroelectrochemistry

High-Power Ultrasonic Synthesis and Magnetic-Field-Assisted Arrangement of Nanosized Crystallites of Cobalt-Containing Layered Double Hydroxides

Contact Info

Product

Resources

About