Structural study of β-Ni(OH)2 and α-Ni(OH)2 variants for electrode applications

Dittrich, H.; Axmann, Peter; Wohlfahrt‐Mehrens, Margret; Garche, Jürgen; Albrecht, Sven; Meese-Marktscheffel, J.; Olbrich, Alfred; Gille, G.

doi:10.1524/zkri.220.2.306.59135

Cited by 4 publications

(6 citation statements)

References 3 publications

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“…Figure b–d shows an overview of the characterization results, and additional characterization figures pertaining to specific items are included in the Supporting Information. The diffraction patterns of all three materials (Figure b) are identical to their standard ones, as were the calculated interlayer distances. − No other diffraction peaks were observed. The oxyhydroxide peaks are broader than those of the starting material, indicating smaller crystal grains.…”

Section: Resultsmentioning

confidence: 98%

Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions

et al. 2023

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The NiOOH electrode is commonly used in electrochemical alcohol oxidations. Yet understanding the reaction mechanism is far from trivial. In many cases, the difficulty lies in the decoupling of the overlapping influence of chemical and electrochemical factors that not only govern the reaction pathway but also the crystal structure of the in situ formed oxyhydroxide. Here, we use a different approach to understand this system: we start with synthesizing pure forms of the two oxyhydroxides, β-NiOOH and γ-NiOOH. Then, using the oxidative dehydrogenation of three typical alcohols as the model reactions, we examine the reactivity and selectivity of each oxyhydroxide. While solvent has a clear effect on the reaction rate of β-NiOOH, the observed selectivity was found to be unaffected and remained over 95% for the dehydrogenation of both primary and secondary alcohols to aldehydes and ketones, respectively. Yet, high concentration of OH– in aqueous solvent promoted the preferential conversion of benzyl alcohol to benzoic acid. Thus, the formation of carboxylic compounds in the electrochemical oxidation without alkaline electrolyte is more likely to follow the direct electrochemical oxidation pathway. Overoxidation of NiOOH from the β- to γ-phase will affect the selectivity but not the reactivity with a sustained >95% conversion. The mechanistic examinations comprising kinetic isotope effects, Hammett analysis, and spin trapping studies reveal that benzyl alcohol is oxidatively dehydrogenated to benzaldehyde via two consecutive hydrogen atom transfer steps. This work offers the unique oxidative and catalytic properties of NiOOH in alcohol oxidation reactions, shedding light on the mechanistic understanding of the electrochemical alcohol conversion using NiOOH-based electrodes.

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Section: Resultsmentioning

confidence: 98%

Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions

et al. 2023

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“…1T-Li 2 NiO 2 may be obtained by the overdischarge of R3 j m LiNiO 2 , although the ground-state of Li 2 NiO 2 is orthorhombic. 37 Both 1T-Li 2 NiO 2 and β-Ni(OH) 2 38 have symmetry P3 j m1. If protons are substituted at the lithium sites of 1T-Li 2 NiO 2 and the system is allowed to relax, under the action of the Hellmann-Feynman forces, it transforms, without energy barriers, to P3 j m1-Ni(OH) 2 by a translation of the protons parallel to the c-axis.…”

Section: Resultsmentioning

confidence: 99%

Free Energy for Protonation Reaction in Lithium-Ion Battery Cathode Materials

2008

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Calculations are performed of free energies for proton-for-lithium-ion exchange reactions in lithiumion battery cathode materials. First-principles calculations are employed for the solid phases and tabulated ionization potential and hydration energy data for aqueous ions. Layered structures, spinel LiMn 2 O 4 , and olivine LiFePO 4 are considered. Protonation is most favorable energetically in layered systems, such as Li 2 MnO 3 and LiCoO 2 . Less favorable are ion-exchange in spinel LiMn 2 O 4 and LiV 3 O 8 . Unfavorable is the substitution of protons for Li in olivine LiFePO 4 , because of the large distortion of the Fe and P coordination polyhedra. The reaction free energy scales roughly linearly with the volume change in the reaction.

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“…The structural model of Ni(SO 4 ) 0.3 (OH) 1.4 can be further constructed by intercalating sulfate and water molecules in the basic β-Ni(OH) 2 structure, owing to the fact that intercalation reaction and layer surface grafting are pervasive in the preparation of layered hydroxide salts. ,, Ni(SO 4 ) 0.3 (OH) 1.4 possesses layered structure and basic units of distorted NiO 6 octahedra as aforementioned. Based on the known structural model of β-Ni(OH) 2 , the structural relationships of NiO, β-Ni(OH) 2 , and Ni(SO 4 ) 0.3 (OH) 1.4 can be illustrated by the schematic representations shown in Figure . A slightly distorted NiO 6 octahedron (blue) is chosen approximately as the basic octahedral unit of NiO.…”

Section: Resultsmentioning

confidence: 99%

“…20,31,32 Ni(SO 4 ) 0.3 (OH) 1.4 possesses layered structure and basic units of distorted NiO 6 octahedra as aforementioned. Based on the known structural model of β-Ni(OH) 2 , 33 the structural relationships of NiO, β-Ni(OH) 2 , and Ni(SO 4 ) 0.3 (OH) 1.4 can be illustrated by the schematic representations shown in Figure 8. A slightly distorted NiO 6 octahedron (blue) is chosen approximately as the basic octahedral unit of NiO.…”

Section: Preliminary Structuralmentioning

confidence: 99%

Structural Evolution of Hydrothermal-Synthesized Ni(SO₄)_0.3(OH)_1.4 Nanobelts During ex Situ Heat Treatment and in Situ Electron Irradiation

et al. 2008

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Nickel hydroxyl sulfate (Ni(SO 4 ) 0.3 (OH) 1.4 ) nanobelts were obtained via a simple template-free hydrothermal reaction. The structural evolution of Ni(SO 4 ) 0.3 (OH) 1.4 nanobelts during ex situ heat treatment and in situ electron irradiation are investigated using transmission electron microscopy (TEM) techniques mainly including bright-field imaging, selected-area electron diffraction combined with kinematic simulations, and high-resolution TEM. The transformation from Ni(SO 4 ) 0.3 (OH) 1.4 to NiO can be observed in both ex situ and in situ experiments. Based on the TEM results, the structural evolution is clarified and the preliminary structural framework of Ni(SO 4 ) 0.3 (OH) 1.4 is proposed. This structural evolution also provides an excellent approach for large-scale production and/or modification of NiO nanoparticles.

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Structural study of β-Ni(OH)₂ and α-Ni(OH)₂ variants for electrode applications

Abstract: Powder samples of

Cited by 4 publications

References 3 publications

Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions

Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions

Free Energy for Protonation Reaction in Lithium-Ion Battery Cathode Materials

Structural Evolution of Hydrothermal-Synthesized Ni(SO₄)_0.3(OH)_1.4 Nanobelts During ex Situ Heat Treatment and in Situ Electron Irradiation

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Structural study of β-Ni(OH)2 and α-Ni(OH)2 variants for electrode applications

Abstract: Powder samples of

Cited by 4 publications

References 3 publications

Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions

Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions

Free Energy for Protonation Reaction in Lithium-Ion Battery Cathode Materials

Structural Evolution of Hydrothermal-Synthesized Ni(SO4)0.3(OH)1.4 Nanobelts During ex Situ Heat Treatment and in Situ Electron Irradiation

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Structural study of β-Ni(OH)₂ and α-Ni(OH)₂ variants for electrode applications

Structural Evolution of Hydrothermal-Synthesized Ni(SO₄)_0.3(OH)_1.4 Nanobelts During ex Situ Heat Treatment and in Situ Electron Irradiation