Next Article in Journal
Heat-Affected Zone Microstructural Study via Coupled Numerical/Physical Simulation in Welded Superduplex Stainless Steels
Previous Article in Journal
The Role of Diamonds Dispersed in Ferronematic Liquid Crystals on Structural Properties
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Crystals
Volume 14
Issue 3
10.3390/cryst14030203
crystals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Technical Note

Selective Synthesis of α-Nickel Hydroxide through a Polyol Process

by
Koki Kawabata
,
Shusuke Okamoto
,
Hironori Hondoh
and
Daisuke Nagai
*
School of Food and Nutritional Science, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
*
Author to whom correspondence should be addressed.
Crystals 2024, 14(3), 203; https://doi.org/10.3390/cryst14030203
Submission received: 1 February 2024 / Revised: 15 February 2024 / Accepted: 17 February 2024 / Published: 21 February 2024
(This article belongs to the Section Inorganic Crystalline Materials)
Browse Figures
Versions Notes

Abstract

:
The polyol process is a straightforward method to produce metallic compounds through transformation from metal salt. An optimized procedure based on the polyol process in this research was developed for the selective synthesis of α-nickel hydroxide from metal salt. From various experimental results, the preparation of the sodium salt of ethylene glycol was crucial for the efficient production of α-nickel hydroxide. The structure of α-nickel hydroxide was studied by powder X-ray diffraction, IR spectroscopy, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscope. The estimated Gibbs free energies for each step of the polyol process, employing density functional theory (DFT) calculations, confirmed the formation of nickel reaction intermediates, which mitigated the production of metallic nickel. The innovative point of this research is the finding that the intentional generation of nickel reaction intermediates leads to selective synthesis of α-nickel hydroxide.

1. Introduction

The need for sustainable energy solutions has stimulated the development of techniques for reusing scarce resources and achieving high-energy storage capabilities [1,2]. The efficient utilization of earth-abundant transition-metal-based materials can fulfill these requirements, due to their cost-effectiveness and high activity [3,4,5,6]. Recently, lithium-ion batteries (LIBs) have been developed for a wide range of electronic applications due to their high specific capacitance, low cost, and reversible redox properties [7,8,9,10]. Such LIBs can be developed from transition metal hydroxides. The selective synthesis of metal hydroxides not only improves the formation efficiency of conventional metal materials but also has great significance in producing new metal materials.
Among these metal hydroxides, nickel hydroxides with electronic properties and a two-dimensional layered structure are widely employed for batteries [7,8,9,10,11] and electrocatalysts [12,13,14,15,16,17]. Nickel hydroxides have three possible crystal structures: α, β, and γ phases. Among them, α-nickel hydroxide, which has a disordered amorphous structure, accommodates various anions and water molecules within the interlayer space due to its border interlayer space [18,19], providing electrochemical properties superior to those of β-nickel hydroxide [20]. Although α-nickel hydroxide is a valuable precursor for metallic materials, its isolation is challenging due to its rapid conversion to β-nickel hydroxide. Several synthetic methods for α-nickel hydroxide have been reported, including electrolysis using urea [17], the sonochemical method [21], and the solvothermal process [22]. In particular, solvothermal methods are attractive because they are simple and can be easily applied to various fields; however, such methods are fewer compared to other methods.
Solution-based synthetic approaches for producing metal compounds offer substantial advantages over electrolysis [23], providing control over size, shape, and product distribution. Among these procedures, the polyol process represents a straightforward method for generating various metal particles [24,25,26,27,28], minimizing the emission of toxic gases during thermal decomposition and preventing contamination of the products by reductants. In a typical polyol process, the conversion of metal ions to metal hydroxides is followed by the reduction of metal hydroxides to metal particles. Ethylene glycol, which is commonly employed in the polyol process, acts not only as a solvent but also produces acetaldehyde as a reducing species, facilitating the reduction of metal hydroxides to metal particles. Because of the rapid progression of such a polyol process, it is difficult to isolate valuable metal hydroxides. Jeyadevan et al. postulated that the formation of metal alkoxide complexes between metal and ethylene glycol is the rate-determining step for the progress of the polyol process [27]. In the present report, the efficient formation of metal reaction intermediates is hypothesized to be the key reaction for selective synthesis of the metal hydroxide. Based on this knowledge, we attempt to adjust ethylene glycol-derived anion or dianion to efficiently generate nickel reaction intermediates, which delay the formation of nickel hydroxide (Figure 1).
This report describes a novel polyol process-based procedure for the selective synthesis of α-nickel hydroxide. An examination of various reaction conditions revealed that the optimum procedure was the addition of a solution of nickel sulfate or nitrate in ethylene glycol to a solution of sodium hydroxide in ethylene glycol. The reaction solution was stirred at 200 °C for 2 h under an argon atmosphere, resulting in the generation of α-nickel hydroxide as the main product. X-ray diffraction (XRD), infrared (IR), and thermogravimetric (TG) analyses of the obtained α-nickel hydroxide indicated intercalation of ethylene glycol molecules between the layers. Based on the estimated Gibbs free energies for stepwise reactions, employing density functional theory (DFT) calculations, some nickel reaction intermediates between nickel ion and ethylene glycol were assumed to contribute to the delay in the formation of α-nickel hydroxide, consequently suppressing the generation of metallic nickel. The polyol process shown in this study is expected to be applied to the making of various metal hydroxides in the future.

2. Materials and Methods

Infrared absorption (IR) spectra were recorded using an FT/IR-4600 series by JASCO Corporation (Tokyo, Japan). X-ray powder diffraction (XRD) patterns were recorded on a Rigaku Corp. (Tokyo, Japan) Ultim Ⅳ, using Cu Kα radiation operated at 40 kV and 10 mA. Transmission electron microscopy (TEM) images were taken on a Hitachi High-Tech Corp. (Tokyo, Japan) HT7700 operated at 112 kV. Scanning electron microscopy (SEM) images were obtained with a Hitachi High-Tech Corp. TM3030. Thermogravimetric analyses were measured using a Seiko Instrument TG-DTA (Shimazu Corp. DTG-60, Kyoto, Japan) under a nitrogen flow rate of 100 mL/min, in a range from 50 to 600 °C at a heating rate of 10 °C/min.
Ethylene glycol (EG) (>99.5%), glycerol (Gly) (>99.5%), nickel (Ⅱ) chloride hexahydrate (>98%), nickel (Ⅱ) nitrate hexahydrate (>98%), nickel (Ⅱ) sulfate hexahydrate (>99%), potassium hydroxide (>85%), sodium hydroxide (>97%), and tetraethylene glycol (TEG) (>95%) were purchased from FUJIFILM Wako Pure Chemical Co., Ltd. (Osaka, Japan). Poly-ethylene glycol (Poly-EG) (average Mn = 400) and 0.45 μm PTFE membrane filter were purchased from Sigma-Aldrich Co., LLC. (Burlington, MA, USA) and used as received. All solvents, such as EG, TEG, Poly-EG, and Gly, were degassed prior to use.

2.1. Synthesis of Metallic Nickel

Table 1, Run 1, Method A
A solution of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) in EG (10 mL) was adjusted using a heat gun and filled into a 20 mL syringe. This prepared reaction solution was added at once to a solution of sodium hydroxide (320 mg; 8.00 mmol) in EG (20 mL) in a two-necked 100 mL flask under an argon atmosphere and the reaction solution was stirred at 200 °C for 2 h. After finishing it, the resulting precipitation was washed with distilled water, collected with a suction filtration through a membrane filter, and dried at room temperature for 12 h under reduced pressure to obtain a black–green powder (112 mg) as a metallic nickel. XRD (2θ): 44.5°, 51.9°, 76.4°, and 93.1°.

2.2. Synthesis of α-Nickel Hydroxide

Table 1, Run 2, Method B
In a 100 mL flask, a solution of sodium hydroxide (320 mg; 8.00 mmol) in EG (10 mL) was stirred at room temperature for 12 h under an argon atmosphere. The separately adjusted solution of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) in EG (10 mL) was added to the above-mentioned solution containing sodium hydroxide using a syringe. The reaction solution was stirred at 200 °C for 2 h and the resulting precipitation was washed with distilled water, collected with a suction filtration through a membrane filter, and dried at room temperature for 12 h under reduced pressure to obtain a bright green solid (440 mg) as a α-nickel hydroxide including EG. IR (ATR, cm−1) ν 3301, 2889, 2853, 1625, 1406, 1351, 1123, 1079, 1057, 876, 656, and 482. XRD (2θ): 10.7°, 34.2°, and 60.9°.
Experiments under various reaction conditions using the method B in Run 2 were investigated (Table 1, Runs 3–12, Method).
In Run 3, the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with potassium hydroxide (1.280 g; 32.00 mmol) in EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a black solid (496 mg).
In Run 4, the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with potassium hydroxide (449 mg; 8.00 mmol) in EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a bright green (452 mg).
In Run 5, the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with sodium hydrogen carbonate (672 mg; 8.00 mmol) in EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a bright green (452 mg).
In Run 6, the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with sodium carbonate (848 mg; 8.00 mmol) in EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a bright green (345 mg).
In Run 7, the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with potassium carbonate (1.11 g; 8.03 mmol) in EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a black–green solid (484 mg).
In Run 8, the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with sodium hydroxide (320 mg; 8.00 mmol) in TEG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a green solid (345 mg).
In Run 9, the reaction of nickel(Ⅱ) sulfate hexahydrate the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with sodium hydroxide (320 mg; 8.00 mmol) in Poly-EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a green solid (437 mg).
In Run 10, the reaction of nickel(Ⅱ) sulfate hexahydrate the reaction of nickel(Ⅱ) sulfate hexahydrate (1.051 g; 3.998 mmol) with sodium hydroxide (320 mg; 8.00 mmol) in Gly (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a dark green solid (437 mg).
In Run 11, the reaction of nickel(Ⅱ) chloride hexahydrate (951 mg; 4.00 mmol) with sodium hydroxide (320 mg; 8.00 mmol) in EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a black powder (218 mg). XRD (2θ): 44.8°, 52.2°, 76.7°, and 93.3°.
In Run 12, the reaction of nickel(Ⅱ) nitrate hexahydrate (1.163 g; 3.999 mmol) with sodium hydroxide (320 mg; 8.00 mmol) in EG (30 mL) was carried out at 200 °C for 2 h under an argon atmosphere to obtain a bright green solid (472 mg). XRD (2θ): 11.1°, 34.7°, and 61.0°.
A solution of sodium hydroxide (80 mg; 2.0 mmol) in EG (1 mL) was stirred at room temperature for 12 h and the reaction solution was concentrated under reduced pressure and dried at room temperature for 12 h to obtain crude EG-Na as a white powder.

3. Results

Reactions of nickel sulfate with a base were conducted under various reaction conditions for the selective synthesis of α-nickel hydroxide as the main product (Scheme 1). The results are presented in Table 1. The reaction involving nickel sulfate and sodium hydroxide in ethylene glycol (EG) in situ was performed at 200 °C for 2 h under an argon atmosphere (Run 1). The resulting precipitate was collected through suction filtration, washed with distilled water, and then dried at room temperature under reduced pressure, yielding the product as a blackish-green solid. Its structure was confirmed by powder XRD analysis (Figure 2).
The XRD patterns depicted in Figure 2A are consistent with the theoretical data for metallic nickel without α and β-nickel hydroxides. This observation suggests that the polyol process employing method A proceeded efficiently with the conversion of nickel sulfate into metallic nickel. During the polyol process utilizing EG, the emergence of acetaldehyde via the condensation reaction of EG is widely acknowledged as a pivotal reductant [25,27,28]. The crude reaction solution was analyzed by 1H NMR, IR, and ESI spectroscopies to confirm the presence of acetaldehyde and deacetyl as by-products, supporting the progress of this reaction through the polyol process. However, the peaks anticipated for each compound were not confirmed, indicating their removal from the reaction system because of their significantly lower boiling points compared to the reaction temperature.
Next, method B of the polyol process was performed, as shown in Scheme 1 (Run 2). Sodium hydroxide and EG were stirred at room temperature for 12 h under an argon atmosphere to produce the sodium salt of ethylene glycol (EG-Na). Subsequently, a solution of nickel sulfate in EG was added to the prepared solution, resulting in a pale green precipitate. The powder XRD patterns depicted in Figure 2B showed characteristic peaks at 10.8°, 34.2°, and 60.9° corresponding to (003), (101), and (110), respectively, derived from α-nickel hydroxide, which agrees with the previously reported data [18,21]. The interlayer space along the c-axis was estimated from the position of each peak to be d = 8.25 Å, 2.62 Å, and 1.52 Å, respectively. The interlayer space at (003) of the synthesized α-nickel hydroxide was broader than those reported for α-nickel hydroxides [18,21], suggesting intercalation of EG molecules between the layers of α-nickel hydroxide. The reflection at d = 2.62 Å indicates the formation of a turbostratic phase, a common feature in α-nickel hydroxide. The three peaks at 20.5°, 45.2°, and 52.5° correspond to a glass plate. The IR spectra in Figure 3A–D represent EG and the synthesized α-nickel hydroxide, respectively. The broad peak from 2997 to 3694 cm−1 in Figure 3B indicates the hydroxyl groups of α-nickel hydroxide, EG, and water. The two peaks attributable to the stretching vibration derived from the two methylene moieties of EG in Figure 3B were confirmed at 2852 and 2886 cm−1, with a shift to lower wavenumbers compared to those of the original EG in Figure 3A, implying interactions between α-nickel hydroxide and EG. A peak at 1631 cm−1 corresponds to the vibration of the interlayer water molecules. The two peaks at 1056 and 1078 cm−1 correspond to stretching vibrations of ether bonds in EG. In the comparison of Figure 3C,D, a characteristic peak at 652 cm−1 in the IR spectrum of α-nickel hydroxide supported in-plane OH deformations. Additionally, a peak attributable to Ni-OH vibrations was observed at 484 cm−1. These analytical results support the successful formation of α-nickel hydroxide, inclusive of EG. To examine the effect of the amount of sodium hydroxide on the reaction behavior of the method B polyol process, an experiment involving 8-fold more sodium hydroxide than that used in conditions in Run 2 (Run 3) was conducted. As shown in Figure 2C, the three peaks associated with α-nickel hydroxide in the XRD patterns of the resulting product decreased significantly compared to those in Run 2 and those attributable to metallic nickel were also not clearly observed. These comparative results suggested that two equivalents of sodium hydroxide to nickel sulfate are suitable.
Based on the method used for Run 2, further controlled experiments were performed utilizing different bases and solvents (Table 1, Runs 4–10). The XRD data for the obtained products are supplied in Supporting Information (Figures S1–S3). The use of potassium hydroxide yielded a product with a highly amorphous structure, preventing its unequivocal identification by XRD analysis (Run 4). Reactions using sodium hydrogen carbonate or potassium carbonate, both soluble in EG, yielded α-nickel hydroxides with lower intensity at 2θ = 10.8° compared to that in Run 2 (Runs 5 and 6). In contrast, the reaction using sodium carbonate, which is insoluble in EG, produced a mixture of α-nickel hydroxide and metallic nickel (Run 7). The base choice strongly influenced the formation of the product. Substituting EG with other solvents, such as tetraethylene glycol (TEG), polyethylene glycol (Poly-EG, average Mn = 400), and glycerol (Gly), produced little α-nickel hydroxide, emphasizing the requirement for EG as a solvent (Runs 8–10). Analogous experiments involving nickel nitrate or nickel chloride as substitutes for nickel sulfate were also performed (Runs 11–12). Nickel nitrate underwent conversion into α-nickel hydroxide, whereas nickel chloride was transformed into metallic nickel. Thus, the efficacy of this polyol process, employing method B, is contingent upon the nature of substrate.
Thermogravimetric analyses (TGA) of the synthesized α-nickel hydroxide in Run 2 and a commercially available β-nickel hydroxide were conducted in the range from 50 to 600 °C under an air atmosphere, as depicted in Figure 4. The TG chart of α-nickel hydroxide shows a gradual progression of thermal decomposition from commencement of the measurement, most likely due to vaporization of EG and water molecules on the surfaces and between the layers. The thermal degradation observed between 250 and 330 °C was attributed to the dehydration of hydroxy groups in α-nickel hydroxide. The XRD patterns of the resulting sample after heating at 600 °C identified it as nickel oxide (NiO) (Figure S4) with a residual weight of 66%, which agrees well with the previously reported residual weight (65%) [21]. The thermal decomposition behavior of β-nickel hydroxide was similar to that of α-nickel hydroxide and its residual weight at 600 °C was 80%. The difference in thermal decomposition of the two different nickel hydroxides was due to the greater solvent content in α-nickel hydroxide compared to that of β-nickel hydroxide.
The dimensions and structure of the synthesized α-nickel hydroxide in Run 2 were examined by transmission electron microscopy (TEM) and scanning electron microscope (SEM). The TEM images presented in Figure 5 indicated that the synthesized α-nickel hydroxide possesses fibrous structures without a definite shape. The size was estimated to be approximately 200 nm in length and 20 nm in width. The SEM images presented in Figure 6 indicated that the synthesized α-nickel hydroxide has the morphology of unshaped structures.

4. Discussion

The Gibbs free energies for the reactions at each stage were estimated using density functional theory (DFT) calculations and the results are shown in Table S1. Based on both experimental and computational results, a reaction mechanism for the synthesis of nickel hydroxide was proposed as shown in Figure 7, representing the polyol process using method B. In the initial stage of the solution of sodium hydroxide in EG, some formation of EG-Na occurs. This was corroborated by the IR spectrum of the prepared solution (Figure S5). Since three different reaction intermediates such as nickel hydroxide EG [Ni(OH)-EG] (Equation (1)), nickel diethylene glycol [Ni(EG)2] (Equation (2)), and nickel ethylene glycol cyclic complex [Ni-EG cyclic complex] (Equation (3)) could be formed under the reaction conditions of method B, the Gibbs free energies for the three were determined using DFT calculations. The computational results supported the spontaneous progression of these reactions. Replacing EG-Na with EG in similar DFT calculations indicated that these reactions are more likely to proceed in the presence of EG-Na (for details, see Supporting Information). The calculated Gibbs free energies for the conversion of reaction intermediates to nickel hydroxide suggested that the formation of Ni(OH)-EG and Ni(EG)2 proceeded spontaneously (Equations (4) and (5)). In contrast, the value for the Ni-EG cyclic complex was positive, indicating that the nucleophilic reaction of hydroxide ions with the cyclic complex is less likely to occur compared to that of other reaction intermediates due to high steric hindrance around the nickel atom (Equation (6)). The NMR and ESI analyses of the reaction solution could not confirm the presence of these reaction intermediates. The experimental and computational results suggest that the formation of such reaction intermediates is the rate-determining step for the production of nickel hydroxide. This hypothesis is consistent with the experimental results from Run 3, presumably because of the formation of more reaction intermediates due to the increase in sodium hydroxide concentration. Because kinetic reaction is also an important factor in determining the reaction mechanism, we attempted to reveal the reaction mechanism in this research from the aspect of kinetic reactions using DFT calculations. In this stage, those accurate calculations have not yet been achieved due to multiple transition states.

5. Conclusions

In conclusion, a novel synthetic procedure based on the polyol process was developed for the selective production of α-nickel hydroxide. The crucial step of the reaction involves the preparation of the sodium salt of ethylene glycol, which serves as a pivotal component in the synthesis of α-nickel hydroxide. A reaction mechanism was proposed for the conversion of nickel salt to nickel hydroxide from the estimated Gibbs free energies for the reactions at each stage using DFT calculations. The computational results confirmed the formation of reaction intermediates between nickel ion and ethylene glycol, which suppress the formation of metallic nickel. The development of this solution-based protocol for synthesizing a metal hydroxide provides a valuable and practical method for the synthesis of various metallic materials.

Supplementary Materials

The following supporting information can be downloaded at https://www.mdpi.com/article/10.3390/cryst14030203/s1. Figure S1: Powder XRD patterns of products using (A) potassium hydroxide in Run 4, (B) sodium hydrogen carbonate in Run 5, (C) potassium carbonate in Run 6, and (D) sodium carbonate in Run 7; Figure S2: Powder XRD patterns of products using (A) TEG in Run 8, (B) Poly-EG in Run 9, and (C) Gly in Run 10; Figure S3: Powder XRD patterns of products using (A) nickel nitrate hexahydrate in Run 11 and (B) nickel chloride hexahydrate in Run 12; Figure S4: Powder XRD patterns of products after heating at 600 °C under an air atmosphere (A) α-nickel hydroxide in Run 2 and (B) a commercially available β-nickel hydroxide; Figure S5: IR spectrum of the crude EG-Na; Table S1: Results of free energies for compounds. XRD, IR, and DFT calculation data presented in this paper have been deposited in the Cambridge Crystallographic Data Center as a Supplementary Publication. These data provided free of charge by the Cambridge Crystallographic Data Centre Access Structures service.

Author Contributions

Conceptualization, K.K., S.O. and D.N.; methodology, K.K. and S.O.; software, K.K. and S.O.; validation, K.K. and S.O.; formal analysis, K.K., S.O. and H.H.; investigation, K.K.; resources, K.K. and D.N.; data curation, K.K.; writing—original draft preparation, K.K.; writing—review and editing, S.O., H.H. and D.N.; visualization, K.K. and S.O.; supervision, D.N.; project administration, D.N.; funding acquisition, D.N. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the JSPS KAKENHI (Grant Number 22H03782) and JFE 21st Century Foundation. (Grant Number 23-551).

Data Availability Statement

The original contributions presented in the study are included in the article and Supplementary Material, further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Liu, J.; Zhang, J.-G.; Yang, Z.; Lemmon, J.P.; Imhoff, C.; Graff, G.L.; Li, L.; Hu, J.; Wang, C.; Xiao, J.; et al. Materials Science and Materials Chemistry for Large Scale Electrochemical Energy Storage: From Transportation to Electrical Grid. Adv. Funct. Mater. 2013, 23, 929–946. [Google Scholar] [CrossRef]
  2. Dunn, B.; Kamath, H.; Tarascon, J.-M. Electrical Energy Storage for the Grid: A Battery of Choices. Science 2011, 334, 928–935. [Google Scholar] [CrossRef]
  3. Wang, J.; Hu, H.; Zhang, H.; Zhao, J.; Li, X.; Song, Z.; Ding, J.; Deng, Y.; Han, X.; Hu, W. Regulating the Catalytically Active Sites in Low-Cost and Earth-Abundant 3d Transition-Metal-Based Electrode Materials for High-Performance Zinc-Air batteries. Energy Fuels 2021, 35, 6483–6503. [Google Scholar] [CrossRef]
  4. Bullock, R.M.; Chen, J.G.; Gagliardi, L.; Chirik, P.J.; Farha, O.K.; Hendon, C.H.; Jones, C.W.; Keith, J.A.; Klosin, J.; Minteer, S.D.; et al. Using nature’s blueprint to expand catalysis with Earth-abundant metals. Science 2020, 369, eabc3183. [Google Scholar] [CrossRef]
  5. Li, A.; Sun, Y.; Yao, T.; Han, H. Earth-Abundant Transition-Metal-Based Electrocatalysts for Water Electrolysis to Produce Renewable Hydrogen. Chem. Eur. J. 2018, 24, 18334–18355. [Google Scholar] [CrossRef]
  6. Xia, W.; Mahmood, A.; Liang, Z.; Zou, R.; Guo, S. Earth-Abundant Nanomaterials for Oxygen Reduction. Angew. Chem. Int. Ed. 2016, 55, 2650–2676. [Google Scholar] [CrossRef]
  7. Wang, L.; Li, J.; He, X.; Pu, W.; Wan, C.; Jiang, C. Recent advances in layered LiNixCoyMn1-x-yO2 cathode materials for lithiumion batteries. J. Solid. State. Electrochem. 2009, 13, 1157–1164. [Google Scholar] [CrossRef]
  8. Liu, W.; Oh, P.; Liu, X.; Lee, M.-J.; Cho, W.; Chae, S.; Kim, Y.; Cho, J. Nickel-Rich Layered Lithium Transition-Metal Oxide for High-Energy Lithium-Ion Batteries. Angew. Chem. Int. Ed. 2015, 54, 4440–4457. [Google Scholar] [CrossRef]
  9. Kalyani, P.; Kalaiselvi, N. Various aspects of LiNiO2 chemistry: A review. Sci. Technol. Adv. Mater. 2005, 6, 689–703. [Google Scholar] [CrossRef]
  10. Whittingham, M.S. Lithium Batteries and Cathode Materials. Chem. Rev. 2004, 104, 4271–4301. [Google Scholar] [CrossRef] [PubMed]
  11. Dai, J.; Li, S.F.Y.; Xiao, T.D.; Wang, D.M.; Reisner, D.E. Structural stability of aluminum stabilized alpha nickel hydroxide as a positive electrode material for alkaline secondary batteries. J. Power Sources 2000, 89, 40–45. [Google Scholar] [CrossRef]
  12. Chen, Y.; Rui, K.; Zhu, J.; Dou, S.X.; Sun, W. Recent Progress on Nickel-Based Oxide/(Oxy)Hydroxide Electrocatalysts for the Oxygen Evolution Reaction. Chem. Eur. J. 2019, 25, 703–713. [Google Scholar] [CrossRef] [PubMed]
  13. Deng, J.; Nellist, M.R.; Stevens, M.B.; Dette, C.; Wang, Y.; Boettcher, S.W. Morphology Dynamics of Single-Layered Ni(OH)2/NiOOH Nanosheets and Subsequent Fe Incorporation Studied by in Situ Electrochemical Atomic Force Microscopy. Nano Lett. 2017, 17, 6922–6926. [Google Scholar] [CrossRef] [PubMed]
  14. Liu, Z.; Li, N.; Zhao, H.; Zhang, Y.; Huang, Y.; Yin, Z.; Du, Y. Regulating the active species of Ni(OH)2 using CeO2: 3D CeO2/Ni(OH)2/carbon foam as an efficient electrode for the oxygen evolution reaction. Chem. Sci. 2017, 8, 3211–3217. [Google Scholar] [CrossRef] [PubMed]
  15. Liu, G.; Li, P.; Zhao, G.; Wang, X.; Kong, J.; Liu, H.; Zhang, H.; Chang, K.; Meng, X.; Kako, T.; et al. Promoting Active Species Generation by Plasmon-Induced Hot-Electron Excitation for Efficient Electrocatalytic Oxygen Evolution. J. Am. Chem. Soc. 2016, 138, 9128–9136. [Google Scholar] [CrossRef] [PubMed]
  16. Miao, Y.; Ouyang, L.; Zhou, S.; Xu, L.; Yang, Z.; Xiao, M.; Ouyang, R. Electrocatalysis and electroanalysis of nickel, its oxides, hydroxides and oxyhydroxides toward small molecules. Biosens. Bioelectron. 2014, 53, 428–439. [Google Scholar] [CrossRef] [PubMed]
  17. Wang, D.; Yan, W.; Botte, G.G. Exfoliated nickel hydroxide nanosheets for urea electrolysis. Electrochem. Commun. 2011, 13, 1135–1138. [Google Scholar] [CrossRef]
  18. Mavis, B.; Akinc, M. Cyanate Intercalation in Nickel Hydroxide. Chem. Mater. 2006, 18, 5317–5325. [Google Scholar] [CrossRef]
  19. Li, J.; Shangguan, E.; Nie, M.; Jin, Q.; Zhao, K.; Chang, Z.; Yuan, X.-Z.; Wang, H. Enhanced electrochemical performance of high-density Al-substituted a-nickel hydroxide by a novel anion exchange method using NaCl solution. Int. J. Hydrogen Energy 2015, 40, 1852–1858. [Google Scholar] [CrossRef]
  20. Delahaye-Vidal, A.; Figlarz, M. Textural and structural studies on nickel hydroxide electrodes. Ⅱ. Turbostratic nickel (Ⅱ) hydroxide submitted to electrochemical redox cycling. J. Appl. Electrochem. 1987, 17, 589–599. [Google Scholar] [CrossRef]
  21. Jeevanandam, P.; Koltypin, Y.; Gedanken, A. Synthesis of Nanosized a-Nickel Hydroxide by a Sonochemical Method. Nano Lett. 2001, 1, 263–266. [Google Scholar] [CrossRef]
  22. Li, Y.; Xie, X.; Liu, J.; Cai, M.; Rogers, J.; Shen, W. Synthesis of a-Ni(OH)2 with hydrotalcite-like structure: Precursor for the formation of NiO and Ni nanomaterials with fibrous shapes. Chem. Eng. J. 2008, 136, 398–408. [Google Scholar] [CrossRef]
  23. Wang, X.; Luo, H.; Parkhutik, P.V.; Millan, A.-C.; Matveeva, E. Studies of the performance of nanostructural multiphase nickel hydroxide. J. Power Sources 2003, 115, 153–160. [Google Scholar] [CrossRef]
  24. Fujieda, S.; Miyamura, W.; Shinoda, K.; Suzuki, S.; Jeyadevan, B. Composition-Controlled Fe–Ni Alloy Fine Particles Synthesized by Reduction-Annealing of Polyol-Derived Fe-Ni Hydroxide. Mater. Trans. 2016, 57, 1645–1651. [Google Scholar] [CrossRef]
  25. Joseyphus, R.J.; Shinoda, K.; Kodama, D.; Jeyadevan, B. Size controlled Fe nanoparticles through polyol process and their magnetic properties. Mater. Chem. Phys. 2010, 123, 487–493. [Google Scholar] [CrossRef]
  26. Joseyphus, R.J.; Kodama, D.; Matsumoto, T.; Sato, Y.; Jeyadevan, B.; Tohji, K. Role of polyol in the synthesis of Fe particles. J. Magn. Magn. Mater. 2007, 310, 2393–2395. [Google Scholar] [CrossRef]
  27. Joseyphus, R.J.; Matsumoto, T.; Takahashi, H.; Kodama, D.; Tohji, K.; Jeyadevan, B. Designed synthesis of cobalt and its alloys by polyol process. J. Solid State Chem. 2007, 180, 3008–3018. [Google Scholar] [CrossRef]
  28. Larcher, D.; Patrice, R. Preparation of Metallic Powders and Alloys in Polyol Media: A Thermodynamic Approach. J. Solid State Chem. 2000, 154, 405–411. [Google Scholar] [CrossRef]
Crystals 14 00203 g001
Figure 1. The concept illustration of this study.
Figure 1. The concept illustration of this study.
Crystals 14 00203 g001
Crystals 14 00203 sch001
Scheme 1. Reactions of nickel salts with bases through a polyol prcess.
Scheme 1. Reactions of nickel salts with bases through a polyol prcess.
Crystals 14 00203 sch001
Crystals 14 00203 g002
Figure 2. Powder XRD patterns of products using (A) Method A in Run 1, (B) Method B in Run 2, and (C) Method B in Run 3.
Figure 2. Powder XRD patterns of products using (A) Method A in Run 1, (B) Method B in Run 2, and (C) Method B in Run 3.
Crystals 14 00203 g002
Crystals 14 00203 g003
Figure 3. IR spectra in the range from 1000 to 4000 cm−1 of (A) EG and (B) α-nickel hydroxide in Run 2. IR spectra in the range from 400 to 800 cm−1 of (C) EG and (D) α-nickel hydroxide in Run 2.
Figure 3. IR spectra in the range from 1000 to 4000 cm−1 of (A) EG and (B) α-nickel hydroxide in Run 2. IR spectra in the range from 400 to 800 cm−1 of (C) EG and (D) α-nickel hydroxide in Run 2.
Crystals 14 00203 g003
Crystals 14 00203 g004
Figure 4. TG thermograms of α-nickel hydroxide in Run 2 and β-nickel hydroxide.
Figure 4. TG thermograms of α-nickel hydroxide in Run 2 and β-nickel hydroxide.
Crystals 14 00203 g004
Crystals 14 00203 g005
Figure 5. TEM images of α-nickel hydroxide in Run 2.
Figure 5. TEM images of α-nickel hydroxide in Run 2.
Crystals 14 00203 g005
Crystals 14 00203 g006
Figure 6. SEM images of α-nickel hydroxide in Run 2.
Figure 6. SEM images of α-nickel hydroxide in Run 2.
Crystals 14 00203 g006
Crystals 14 00203 g007
Figure 7. A postulated reaction mechanism for the synthesis of nickel hydroxide.
Figure 7. A postulated reaction mechanism for the synthesis of nickel hydroxide.
Crystals 14 00203 g007
Table 1. Results of reactions of nickel salts with bases through a polyol process 1.
Table 1. Results of reactions of nickel salts with bases through a polyol process 1.
Run.MethodNickel SaltBaseSolvent
1ANiSO4 (4 mmol)NaOH (8 mmol)EG
2BNiSO4 (4 mmol)NaOH (8 mmol)EG
3BNiSO4 (4 mmol)NaOH (32 mmol)EG
4BNiSO4 (4 mmol)KOH (8 mmol)EG
5BNiSO4 (4 mmol)NaHCO3 (8 mmol)EG
6BNiSO4 (4 mmol)Na2CO3 (8 mmol)EG
7BNiSO4 (4 mmol)K2CO3 (8 mmol)EG
8BNiSO4 (4 mmol)NaOH (8 mmol)TEG
9BNiSO4 (4 mmol)NaOH (8 mmol)Poly-EG
10BNiSO4 (4 mmol)NaOH (8 mmol)Gly
11BNi(NO3)2 (4 mmol)NaOH (8 mmol)EG
12BNiCl2 (4 mmol)NaOH (8 mmol)EG
1 Reactions of nickel salts with bases were performed in a solvent at 200 °C for 2 h under Ar.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Kawabata, K.; Okamoto, S.; Hondoh, H.; Nagai, D. Selective Synthesis of α-Nickel Hydroxide through a Polyol Process. Crystals 2024, 14, 203. https://doi.org/10.3390/cryst14030203

AMA Style

Kawabata K, Okamoto S, Hondoh H, Nagai D. Selective Synthesis of α-Nickel Hydroxide through a Polyol Process. Crystals. 2024; 14(3):203. https://doi.org/10.3390/cryst14030203

Chicago/Turabian Style

Kawabata, Koki, Shusuke Okamoto, Hironori Hondoh, and Daisuke Nagai. 2024. "Selective Synthesis of α-Nickel Hydroxide through a Polyol Process" Crystals 14, no. 3: 203. https://doi.org/10.3390/cryst14030203

APA Style

Kawabata, K., Okamoto, S., Hondoh, H., & Nagai, D. (2024). Selective Synthesis of α-Nickel Hydroxide through a Polyol Process. Crystals, 14(3), 203. https://doi.org/10.3390/cryst14030203

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop