JP-2026075516-A - Ammonia storage material
Abstract
[Problem] To provide an ammonia storage material that can absorb and release ammonia by pressure manipulation and has excellent reversible ammonia absorption and release characteristics. [Solution] The solution comprises a salt of at least one metal selected from alkali metals, alkaline earth metals, and transition metals, and a fluorocomplex. [Selection Diagram] Figure 1
Inventors
- 劉 醇一
- 徳重 学
Assignees
- 国立大学法人千葉大学
Dates
- Publication Date
- 20260508
- Application Date
- 20241022
Claims (5)
- An ammonia storage material characterized by containing a salt of at least one metal selected from alkali metals, alkaline earth metals, and transition metals, and a fluorocomplex.
- The ammonia storage material according to claim 1, characterized in that the fluorocomplex is a tetrafluoroborate ion.
- The ammonia storage material according to claim 1, characterized in that the fluorocomplex is a hexafluorophosphate ion.
- The ammonia storage material according to any one of claims 1 to 3, characterized in that the aforementioned metal is sodium.
- The ammonia storage material according to any one of claims 1 to 3, characterized in that the aforementioned metal is potassium.
Description
This invention relates to an ammonia storage material capable of absorbing and releasing ammonia. In recent years, carbon dioxide emission regulations have necessitated a reduction in the use of fossil fuels. Hydrogen, which does not release carbon dioxide through oxidation or combustion, is attracting attention as a next-generation fuel to replace fossil fuels, and the use of ammonia ( NH3 ) as a storage and transportation medium for this hydrogen is being considered. The Haber-Bosch process, using hydrogen and nitrogen, has been the industrial method for synthesizing and producing ammonia. However, the synthesized ammonia needs to be separated and recovered from the unreacted hydrogen and nitrogen. Conventional separation and recovery processes for ammonia have included deep cooling recovery, which utilizes the difference in boiling points between the synthesized ammonia and the unreacted gases (hydrogen and nitrogen) for liquefaction, and water dissolution separation, which utilizes the difference in solubility in water. However, these separation and recovery processes have problems such as energy costs and contamination by water vapor. To solve these problems, development of ammonia storage materials using materials that exhibit selective ammonia storage characteristics is underway. For example, the ammonia storage material described in Patent Document 1 uses a combination of metal halides such as calcium chloride ( CaCl₂ ) and calcium bromide ( CaBr₂ ), allowing synthesized ammonia to be selectively absorbed and released by pressure operation (PSA) or temperature operation (TSA). Japanese Patent Publication No. 4745299 (page 4, Figure 8) This figure shows an example of the three-dimensional structure of tetrafluoroborate ( NaBF4 ) contained in the ammonia storage material of the embodiment.This figure shows an example of the stereostructure of hexafluorophosphate ( KPF6 ) contained in the ammonia storage material of the embodiment.(a) is a diagram showing the ammonia storage and release behavior of the ammonia storage material ( NaBF4 ) in Example 1 at 27°C, and (b) is a diagram showing the ammonia storage and release behavior of the ammonia storage material ( KPF6 ) in Example 1 at 27°C. Hereafter, in the diagrams showing the ammonia storage and release behavior, the solid line graph represents the ammonia storage capacity, and the dotted line graph represents the ammonia pressure.(a) is a diagram showing the ammonia storage and release behavior of a conventional ammonia storage material ( CaCl₂ ) at 27°C, and (b) is a diagram showing the ammonia storage and release behavior of a conventional ammonia storage material (Na-Y zeolite) at 27°C.This figure compares the ammonia storage and release characteristics of various fluorocomplex salts ( NaBF₄ , LiBF₄ , NaPF₆ , KPF₆ ) used as ammonia storage materials in Example 1 and a conventional ammonia storage material ( CaCl₂ , Na-Y zeolite).(a) is a figure showing the XRD patterns of the ammonia storage material ( NaBF4 ) in Example 1 before and after ammonia storage, and (b) is a figure showing the XRD patterns of the ammonia storage material ( KPF6 ) in Example 1 before and after ammonia storage.(a) is a figure showing the FT-IR spectra of the ammonia storage material ( NaBF4 ) in Example 1 before and after ammonia storage, and (b) is a figure showing the FT-IR spectra of the ammonia storage material ( KPF6 ) in Example 1 before and after ammonia storage.(a) is a diagram showing the ammonia storage and release behavior of the ammonia storage material ( NaBF4 ) in Example 2 at 27°C, (b) is a diagram showing the ammonia storage and release behavior at 50°C, (c) is a diagram showing the ammonia storage and release behavior at 100°C, and (d) is a diagram showing the ammonia storage and release behavior at 200°C. The embodiments of the present invention will be described below. However, the present invention can be implemented in many different forms and is not limited to the embodiments and examples shown below. The ammonia storage material according to this embodiment contains a salt of at least one metal selected from alkali metals, alkaline earth metals, and transition metals, and a fluorocomplex. The fluorocomplex may be tetrafluoroborate ion ( BF4- ) , hexafluorophosphate ion ( PF6- ), hexafluoroaluminate ion ( AlF63- ), hexafluorosilicate ion ( SiF62- ), hexafluorotitanate ion (TiF62- ) , hexafluorotungstate ion ( WF62- ), etc., but from the viewpoint of increasing the ratio of release capacity to ammonia ( NH3 ) storage capacity, tetrafluoroborate ion ( BF4- ) or hexafluorophosphate ion ( PF6- ) is preferred. Furthermore, the metal may be any alkali metal, alkaline earth metal, or transition metal, as long as it can form a salt with the fluorocomplex. However, from the viewpoint of facilitating the formation of a stable salt, it is preferable that the metal be an alkali metal or alkaline earth metal, and particularly preferable that it be an alkali metal