Unconventional phase hexagonal prussian blue analogue with open structure

Abstract

The present invention relates to a simple synthesis method for the synthesis of a novel hexagonal phase CuCo (H-CuCo) Prussian blue analogue (PBA) having a high degree of crystallinity, and to the extended synthesis of the following doped PBA having a hexagonal phase: Fe < 0.1 >-Cu < Co >, Fe < 0.2 >-Cu < Co >, Co < 0.1 >-Cu < Co >, Ni < 0.1 >-Cu < Co >, and Zn < 0.1 >-Cu < Co >. The hexagonal phase H-CuCo PBA and the doped PBA having the hexagonal phase exhibit superior crystallinity and a higher intrinsic specific surface area. Meanwhile, H-CuCo PBA shows greater gas adsorption potential, and has a positive influence on the development of PBA for other applications.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Patent Application No. 18 / 748,123, filed June 20, 2024, which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention relates to the fields of materials science and chemistry, and more specifically to synthetic chemistry and materials synthesis techniques. Background Technology

[0003] As members of the family of microporous inorganic solids, Prussian blue (PB) and its analogues (PBA) have shown broad application prospects in numerous fields such as catalysis, gas storage, energy storage, photothermal therapy, drug delivery, sensors, and nanozymes. PBA is an octahedral [M'(CN)6] n- Complexes, the complexes being M-linked by nitrogen in octahedral coordination. n+ Ionic bonding, and always with Cu3[Co(CN)6]2 and M[M'(CN)6] n- Cubic structure of vacancy association ( The space group, cubic system, and lattice form are corresponding to neutral-oriented cubic structures, where M and M' are typically early transition metals (M = Cu, Co, Ni, Fe, Zn, etc., M' = Mn, Fe, Co). These can be used to maintain electroneutrality.

[0004] To meet specific needs, defect engineering strategies are typically employed, which involve introducing [M'(CN)6] defects or cyano(CN) defects to modulate PBA (see Figure 1 However, the aperiodic and random distribution of defects poses a significant obstacle to the study of atomic-scale crystal structures. Specifically, the challenge lies in the fact that the growth of single crystals of PBA is limited during synthesis due to the rapid formation of microcrystalline structures. Furthermore, the presence of defects makes the PBA structure brittle and prone to collapse. In addition, the inherently low specific surface area of ​​conventional cubic PBA constitutes a major obstacle to its application development. This limitation is particularly critical because many applications heavily rely on the specific surface area of ​​PBA, such as gas storage. Therefore, developing a novel synthetic strategy to control the crystallinity of PBA and increase its specific surface area is crucial to its development.

[0005] Phase engineering is considered an effective method for controlling crystal structure, which can significantly influence the chemical and physical properties of materials. This method involves manipulating factors such as atomic arrangement, electronic structure, and coordination number. Phase engineering has been successfully applied to a variety of materials, including metals, metal oxides, Group IVA metal chalcogenides, and transition metal dichalcogenides (TMDs).

[0006] Pal, Shyam Chand, and others 1 Cubic CuCo PBA has been disclosed as having promising potential for CO2 adsorption and CO2 / CH4 separation in breakthrough simulation studies. However, no studies on the practical application of PBA in CO2 / CH4 separation have been published.

[0007] Based on the above discussion, the field still lacks a major breakthrough: the development of a new synthetic strategy to overcome the defects of PBA, enhance control over its crystal structure, and increase its specific surface area. Summary of the Invention

[0008] This invention aims to overcome the limitations of conventional Prussian blue analogues (PBAs) by developing a novel synthetic strategy that enhances control over crystal structure, increases specific surface area, and improves the adsorption capacity for small molecules, including CO2. Furthermore, this invention aims to achieve practical CO2 / CH4 separation and C3H6 / C2H4 separation using PBAs.

[0009] In a first aspect, the present invention provides a hexagonal copper-cobalt Prussian blue analog material comprising 30-40 wt% copper, 10-30 wt% cobalt, 10-30 wt% carbon, and 10-30 wt% nitrogen. Each copper ion is coordinated with four cyano groups to exhibit a planar quadrilateral configuration, while each copper ion is connected with six cyano groups to exhibit an octahedral configuration.

[0010] In one embodiment, the hexagonal copper-cobalt Prussian blue analogue material is capable of forming prism-shaped crystals.

[0011] In one embodiment, the 2θ values ​​of the hexagonal copper-cobalt Prussian blue analog material are 13.9°, 14.4°, 16.0°, 20.1°, 21.7°, 22.1°, 23.2°, 25.1°, 25.5°, 26.2°, 29.1°, 29.9°, 31.1°, 32.4°, 36.1°, 37.1°, and 37.9°. °, 38.8°, 39.5°, 40.8°, 41.7°, 44.9°, 45.8°, 46.2°, 47.1°, 50.2°, 51.6°, 52.4°, 53.2°, 53.9°, 55.3°, 57.5°, 57.8°, 58.9°, 61.2°, 61.7°, 62.9°, 64.0°.

[0012] In one embodiment, the hexagonal copper-cobalt Prussian blue analog material exhibits a hexagonal lattice structure.

[0013] In one embodiment, the specific surface area of ​​the hexagonal copper-cobalt Prussian blue analog material is at least 1000 m².2 g -1 .

[0014] Preferably, the specific surface area of ​​the hexagonal copper-cobalt Prussian blue analog material is at least 1200 m². 2 g -1 .

[0015] In one embodiment, the hexagonal copper-cobalt Prussian blue analog material has larger channels and interstitial spaces for metal ion storage and diffusion.

[0016] In one embodiment, the hexagonal copper-cobalt Prussian blue analogue material exhibits three types of pores, the half-pore width of which is... and

[0017] In one embodiment, the hexagonal copper-cobalt framework contains numerous unsaturated copper sites.

[0018] In one embodiment, the hexagonal copper-cobalt Prussian blue analogue material exhibits numerous Cu... I And Cu-N≡C-Co with low coordination number.

[0019] In one embodiment, the hexagonal copper-cobalt Prussian blue analog material exhibits gas adsorption properties that are at least 1.5 times greater than those of cubic PBA.

[0020] In one embodiment, the gas includes CO2, CH4, C2H2, C2H4, C2H6, C3H6, and C3H8.

[0021] In one embodiment, the hexagonal copper-cobalt Prussian blue analog exhibits superior separation performance for C3H6 / C2H4 and CO2 / CH4 compared to cubic Prussian blue analog materials.

[0022] In another embodiment, the hexagonal copper-cobalt Prussian blue analog material is further doped with one or more metal precursors. The one or more metal precursors include FeCl3, NiCl2, or ZnCl2 or their hydrates.

[0023] In another aspect, the present invention provides a method for synthesizing hexagonal copper-cobalt Prussian blue analogues, the method comprising: adding deionized water containing CuCl2·2H2O and sodium citrate to a mixed solution of deionized water and dimethylformamide (DMF) containing K3Co(CN)6 and polyvinylpyrrolidone (PVP) to obtain a first solution; continuously stirring the first solution in a water bath at 30°C for 24-48 hours; centrifuging the first solution and collecting the precipitate; washing the collected precipitate at least three times with deionized water and ethanol; and drying the collected sample at 80°C for 10-15 hours. The method does not require high-temperature treatment or any other post-treatment.

[0024] In one embodiment, the hexagonal copper-cobalt Prussian blue analogue material is capable of forming prism-shaped crystals.

[0025] In another embodiment, the first solution further comprises one or more metal precursors. The one or more metal precursors include FeCl3, NiCl2, or ZnCl2 or their hydrates.

[0026] Through phase engineering, this invention provides a simple and universal co-precipitation method for synthesizing hexagonal PBA with high crystallinity (including hexagonal copper-cobalt (H-CuCo) PBA), as well as extended synthesis of the following doped PBA with hexagonal phase: Co 0.1 -CuCo, Fe 0.1 -CuCo, Fe 0.2 -CuCo, Ni 0.1 -CuCo and Zn 0.1 -CuCo.

[0027] The hexagonal H-CuCo PBA developed in this invention has a higher specific surface area (1273.24 m²). 2 g -1 The hexagonal H-CuCoPBA developed in this invention provides larger channels for metal ion storage and diffusion. Therefore, compared to cubic CuCo PBA, the hexagonal H-CuCoPBA exhibits superior performance. Furthermore, its gas adsorption (e.g., CO2) capacity is significantly enhanced (1.5 times that of cubic CuCo PBA). This breakthrough enables highly efficient separation of C3H6 / C2H4 from CO2 / CH4, thereby significantly advancing gas adsorption and separation technologies. Attached Figure Description

[0028] Embodiments of the invention are described in more detail below with reference to the accompanying drawings, in which:

[0029] Figure 1The conventional cubic PBA obtained by conventional vacancy engineering and the novel hexagonal PBA obtained by phase engineering are shown (all water molecules and antications are omitted for clarity).

[0030] Figure 2 The synthesis diagram of H-CuCo is shown;

[0031] Figure 3A XRD patterns of H-CuCo and C-CuCo were depicted. Figure 3B A three-dimensional electron diffraction pattern is shown. Figure 3C XPS values ​​for Co and Cu elements were depicted. Figure 3D XPS spectra of H-CuCo and C-CuCo were depicted;

[0032] Figure 4A The solution after KCl was exchanged for H-CuCo was described. 1 H NMR spectrum. Figure 4B TGA curves for H-CuCo and C-CuCo were plotted;

[0033] Figure 5A The SEM image of H-CuCo is shown. Figure 5B The SEM image of H-CuCo is shown. Figure 5C A TEM image of H-CuCo is shown. Figure 5D The SEM image of C-CuCo is shown. Figure 5E A TEM image of C-CuCo is shown. Figure 5F It shows along SAED image of the zone axis. Figure 5G It shows from Figure 5C The HRTEM image is cropped from the region marked by the white box in the figure. The inset shows the corresponding Fast Fourier Transform (FFT) result. Figure 5H A side view of the H-CuCo lattice structure is shown. Figure 5I High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images and elemental plots of Cu, Co, C, and N are shown.

[0034] Figure 6A The EDS spectrum of H-CuCo was depicted. The illustrations show the detailed elemental ratios. Figure 6B The EDS spectra of C-CuCo were depicted. The insets show detailed elemental ratios.

[0035] Figure 7A Fe 0.1 -CuCo, Fe 0.2 -CuCo, Co 0.1 -CuCo, Ni 0.1 -CuCo and Zn0.1 SEM image of CuCo. Figure 7B Fe 0.1 -CuCo, Fe 0.2 -CuCo, Co 0.1 -CuCo, Ni 0.1 -CuCo and Zn 0.1 TEM image of CuCo. Figure 7C Fe 0.1 -CuCo, Fe 0.2 -CuCo, Co 0.1 -CuCo, Ni 0.1 -CuCo and Zn 0.1 HAADF-STEM image of CuCo. Figure 7D Fe 0.1 -CuCo, Fe 0.2 -CuCo, Co 0.1 -CuCo, Ni 0.1 -CuCo and Zn 0.1 XRD pattern of CuCo;

[0036] Figure 8 Depicting Co 0.1 -CuCo, Fe 0.1 -CuCo, Fe 0.2 -CuCo, Ni 0.1 -CuCo and Zn 0.1 XPS spectra of Cu element in CuCo;

[0037] Figure 9 XDR spectra of H-CuCo and C-CuCo before and after heating at 100 °C under vacuum conditions were depicted.

[0038] Figure 10A The N2 adsorption-desorption isotherms of H-CuCo and C-CuCo at 77 K were plotted. Figure 10B The pore size distributions of H-CuCo and C-CuCo were depicted. Figure 10C The gas adsorption isotherms of H-CuCo and C-CuCo for CO2, CH4, C2H2, C2H, C2H6, C3H6 and C3H8 at 273 K and 298 K, 1 bar, were depicted.

[0039] Figure 11 Column breakthrough experiments of H-CuCo and C-CuCo in C3H6 / C2H4 were described;

[0040] Figure 12 Experimental column breakthrough curves for CO2 / CH4 separation of H-CuCo and C-CuCo were plotted.

[0041] Figure 13A Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 -BET test results for CuCo. Figure 13B Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 CO2 adsorption performance of CuCo at 273 K and 298 K. Figure 13C Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 CH4 adsorption properties of CuCo at 273 K and 298 K. Figure 13D Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 CH4 adsorption properties of CuCo at 273 K and 298 K. Figure 13E Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 - Adsorption properties of CuCo for C2H4 at 273 K and 298 K. Figure 13F Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 - Adsorption properties of CuCo for C2H6 at 273 K and 298 K. Figure 13G Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 -Adsorption properties of CuCo on C3H6 at 273 K and 298 K. Figure 13H Describing Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 -Adsorption properties of CuCo on C3H8 at 273 K and 298 K;

[0042] Figure 14A XANES spectra of H-CuCo, C-CuCo, and reference materials were depicted. Figure 14B Fourier transform spectra of EXAFS derived from H-CuCo, C-CuCo and reference materials were depicted. Figure 14C WT-EXAFS spectra of Co in H-CuCo, C-CuCo, K3Co(CN)6 and Co foil were depicted. Figure 14DThe corresponding WT-EXAFS values ​​of Co for H-CuCo, C-CuCo, Cu2O, CuO, and CuPc were depicted; and

[0043] Figure 15A An EXAFS fit of the Co element is depicted, showing the K-space and R-space data of H-CuCo and the fitting results. Figure 15B An EXAFS fit of the Co element is depicted, showing the K-space and R-space data of C-CuCo and the fitting results. Figure 15C An EXAFS fit of Cu was depicted, showing the K-space and R-space data of H-CuCo and the fitting results. Figure 15D An EXAFS fit of Cu was depicted, showing the K-space and R-space data of C-CuCo and the fitting results. Detailed Implementation

[0044] Generally, existing PBAs have an fcc structure, characterized by low specific surface area and numerous defects, which may limit their application development. Cubic Prussian blue and its analogues are coordination compounds that remain stable at room temperature and pressure. PBAs have great potential in multiple fields. However, the randomly distributed defects and inherent properties of conventional cubic PBAs pose challenges to their research and development.

[0045] Therefore, this invention provides a hexagonal copper-cobalt Prussian blue analog material comprising 30-40 wt% copper, 10-30 wt% cobalt, 10-30 wt% carbon, and 10-30 wt% nitrogen. Each copper ion is coordinated with four cyano groups to exhibit a planar quadrilateral configuration, while each copper ion is linked with six cyano groups to exhibit an octahedral configuration. The open framework structure of PBA includes channels and interstitial spaces that facilitate the rapid diffusion of various carrier ions and small molecules. The invention of hexagonal PBA (e.g., hexagonal H-CuCo PBA) not only provides a higher specific surface area but also provides larger open channels and interstitial spaces. This allows for greater capacity to store ions and small molecules, as well as faster diffusion and release rates of carriers.

[0046] In one embodiment, the hexagonal copper-cobalt Prussian blue analog material can form prism-shaped crystals. In addition to prism-shaped crystals, the hexagonal copper-cobalt Prussian blue analog material can also form the following crystal shapes: rhombic crystals, hexagonal prism crystals, octahedral crystals, etc.

[0047] The hexagonal H-CuCo PBA exhibits a planar crystal structure with Cu atoms. X-ray absorption fine structure analysis revealed numerous unsaturated Cu sites within the framework of H-CuCo.

[0048] Highly crystalline H-CuCo PBA provides at least 1000m 2 g -1 High specific surface area.

[0049] Preferably, highly crystalline H-CuCo PBA provides 1273.24m. 2 g -1 High specific surface area.

[0050] The gas adsorption performance achieved by highly crystalline H-CuCo PBA is approximately 1.5 times that achieved by conventional cubic CuCo PBA. Specifically, the CO2 uptake capacity of H-CuCo is 6.09 mmol g. -1 and 4.18 mmol g -1 (Under the conditions of 273K and 298K, 1 bar).

[0051] H-CuCo PBA also exhibits superior gas separation performance, with the separation coefficient for C3H6 and C2H4 being twice that of cubic CuCo PBA, and breakthroughs were achieved in CO2 / CH4 separation. This impressive performance is attributed to the presence of numerous unsaturated copper sites within the H-CuCo PBA framework.

[0052] In another aspect, the present invention provides a method for preparing H-CuCo PBA having a hexagonal phase, the method comprising: Deionized water containing CuCl2·2H2O and sodium citrate was added to a mixed solution of deionized water and DMF containing K3Co(CN)6 and PVP to obtain a first solution. The first solution was stirred continuously in a 30°C water bath for 24-48 hours; Centrifuge the first solution and collect the precipitate; The collected precipitate was rinsed at least three times with deionized water and ethanol; and Dry the collected samples at 80°C for 10-15 hours.

[0053] In another aspect, the present invention provides a doped H-CuCo PBA with a hexagonal phase structure, which is prepared by adding small amounts of different metal precursors. Large-scale production can be achieved by proportionally increasing the precursor concentration, indicating that the novel hexagonal H-CuCo PBA has greater potential for industrial production.

[0054] In another aspect, the present invention provides a method for preparing doped H-CuCo PBA having a hexagonal phase, the method comprising: adding deionized water containing CuCl2·2H2O, a metal chloride precursor, and sodium citrate to a mixed solution of deionized water and DMF containing K3Co(CN)6 and PVP to obtain a first solution; continuously stirring the first solution in a water bath at 30°C for 24-48 hours; collecting the precipitate by centrifugation; washing the collected precipitate at least three times with deionized water and ethanol, respectively; and drying the collected sample at 80°C for 10-15 hours.

[0055] In one embodiment, the precursor of the metal chloride may be FeCl3, NiCl2, or ZnCl2 or their hydrates.

[0056] In one embodiment, the concentration of the metal chloride precursor is less than 0.04 mmol.

[0057] In one embodiment, the concentration of sodium citrate is in the range of 0.1-0.5 mmol.

[0058] In one embodiment, the ratio of deionized water to DMF in the mixed solution is 2:5.

[0059] In summary, this invention develops a simple and low-cost method for preparing novel hexagonal CuCo Prussian blue analogs with a large number of unsaturated Cu atoms through phase engineering. The hexagonal lattice structure of H-CuCo was confirmed using 3D electron diffraction, in which Cu ions with four N-linked cyano groups adopt a planar quadrilateral configuration, while Co ions with six C-linked cyano groups form an octahedral configuration, thus creating a 12-ring pore channel. Compared to conventional cubic CuCo PBA, this hexagonal PBA exhibits significantly enhanced CO2 adsorption performance and also shows improvements in the adsorption capacities for CH4, C2H2, C2H4, C2H6, C3H6, and C3H8. Furthermore, H-CuCo PBA demonstrates superior performance in C3H6 / C2H4 separation compared to cubic PBA and achieves a breakthrough in CO2 / CH4 separation.

[0060] Furthermore, XPS and XAFS tests confirmed the presence of a large amount of Cu in H-CuCo PBA. I The low coordination number of H-CuCo PBA, attributed to its unconventional hexagonal phase, indicates that many Cu atoms in H-CuCo PBA are unsaturated and in open states. This may explain the significantly better performance of H-CuCo PBA. Furthermore, a series of CuCo PBAs with hexagonal phase dopants have been developed. This doping strategy allows for modulation of the morphology and number of unsaturated Cu atoms.

[0061] In the following description, specific details are provided for purposes of explanation and not limitation, in order to help to fully understand the invention.

[0062] Example

[0063] Example 1

[0064] Materials and methods

[0065] Potassium hexacyanocobalaminate (K3Co(CN)6, 99%), PVP (molecular weight 58,000), cobalt chloride hexahydrate (CoCl2·6H2O, AR), copper chloride dihydrate (CuCl2·2H2O, AR), nickel chloride hexahydrate (NiCl2·6H2O, AR), zinc chloride (ZnCl2, ACS grade), and sodium citrate (Na3C6H5O7, AR, 99%) were purchased from Shanghai Aladdin. Ferric chloride hexahydrate (FeCl3·6H2O, AR) was purchased from Dieckmann. Ethanol (ACS grade, absolute) was purchased from AnaquaGlobal International Inc. Limited. Dimethylformamide (DMF, AR) was purchased from RCl Labscan. All chemicals and materials were used as is without any further purification.

[0066] Characterization

[0067] The synthesized samples were identified using Kα rays emitted from Cu via X-ray diffraction (XRD) (SmartLab, 40 kV). Scanning electron microscopy (SEM) samples were prepared by dropping a suspension onto a silicon substrate and drying it under ambient conditions. SEM images were collected on a QUATTRO S SEM operating at 20 kV. Transmission electron microscopy (TEM) images were acquired on a JEOL JEM-2100F. The samples were analyzed on a PerkinElmer STA6000 analyzer under N2 flow at 10 °C / min. -1 Thermogravimetric analysis (TGA) was performed at rates ranging from 30°C to 650°C.

[0068] X-ray photoelectron spectroscopy (XPS) was performed using an ESCALAB-MKII spectrometer with an Al Kα X-ray source, using C1s (284.5 eV) as a reference. X-ray absorption spectroscopy was performed in transmission mode using a beamline X-ray absorption fine structure (XAFCA) for catalysis at a beam current of 200 mA and operating at 700 MeV at the Singapore Synchrotron Light Source. Data processing was performed using Athena and Artemis software packages. The KCl-exchanged solution was analyzed by nuclear magnetic resonance spectroscopy (NMR 300 MHz, Bruker AVANCE III BBO probe). H-CuCo and Co were confirmed by inductively coupled plasma atomic emission spectrometry (ICP-OES, Platinum Elmer, Optima 8000). 0.1 -CuCo, Fe 0.1 -CuCo, Ni-CuCo: the ratio of Cu to Co.

[0069] Single-component static adsorption

[0070] For porosity analysis, an Autosorbi Q2 adsorption analyzer from Quantachrome Instruments was used to perform nitrogen adsorption-desorption experiments at 77 K. Adsorption isotherms for gases such as CO2 and N2 were also recorded at 273 K and 298 K on the same instrument. Approximately 50 mg of freshly prepared sample was activated under high vacuum at 100 °C for 12 hours prior to gas adsorption measurements.

[0071] Adsorption-penetration experiment

[0072] Transmission experiments of C3H6 / C2H4 were conducted at 273 K using a multicomponent adsorption-transmission apparatus. All experiments were performed using columns with an inner diameter of 6 mm and a height of approximately 45 nm. The weight of the packaged samples ranged from 0.4 g to 0.6 g. The column packed with the sample was first activated at 100 °C for 720 min, and then subjected to a He flow (20 mL min) at the target temperature. -1 Purge. Use 5 mL min -1 A mixed gas (50 / 50, v / v) stream was introduced. The outlet gas from the column was monitored using thermal conductivity detector (TCD) online mass spectrometry (BSD-MASS).

[0073] CO2 / CH4 breakthrough experiments were conducted at 298 K using a laboratory-grade fixed-bed reactor. In a typical experiment, the powder was activated at 373 K for 24 hours, and then 100 mg of material was packaged into a quartz column (5.8 mm ID × 150 mm) with silane-treated glass wool filling the void spaces. A helium flow rate (1 mL / min) was used. -1 The adsorbent was purged at 373 K for 5 hours, and the system was cooled to 298 K. The helium flow was then disconnected, while allowing a mixture of CO2 and CH4 (50 / 50, v / v) to be released at 1 mL / min. -1 The effluent flows into the column at a rate that allows it to pass through. The effluent from the column is monitored using an online mass spectrometer.

[0074] Example 2

[0075] Synthesis of hexagonal CuCo Prussian blue analogue materials (H-CuCo)

[0076] refer to Figure 1 Instead of using vacancies or not using vacancies in conventional methods to prepare cubic phase PBA (C-CuCo), a hexagonal phase copper cobalt Prussian blue analog material (referred to as H-CuCo) was synthesized using a phase engineering strategy and a simple coprecipitation method. Figure 2 The synthesis process of H-CuCo is shown, which does not require high-temperature treatment or any other post-treatment.

[0077] For the synthesis of H-CuCo, a simple coprecipitation method was used. 5 mL of deionized water containing 0.2 mmol CuCl₂·2H₂O and 0.2 mmol sodium citrate was added to a mixed solution containing 5 mL of deionized water and 25 mL of DMF, in which 0.2 mmol K₃Co(CN)₆ and 0.2 g PVP were dissolved. The solution was then stirred continuously in a 30°C water bath for 48 hours. After the reaction was complete, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. Finally, the collected sample was dried at 80°C for 12 hours.

[0078] Synthetic cubic CuCo PBA cube (C-CuCo)

[0079] 15 ml of deionized water containing 0.145 g Cu(NO3)2 and 0.75 mmol sodium citrate was added to 15 ml of deionized water containing 0.133 g K3Co(CN)6, and the mixture was stirred at ambient temperature for 12 hours. Upon completion of the reaction, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. Finally, the collected sample was dried in an oven at 80 °C for 12 hours.

[0080] Example 3 - Characterizing PBA

[0081] Turning Figure 3A The XRD patterns show that the XRD patterns of C-CuCo are consistent with those of conventional PBA. The fcc phase is present in H-CuCo, and its XRD pattern is completely different from that of C-CuCo. Both sharp and broad peaks are visible in the XRD pattern of H-CuCo, indicating possible disordered stacking in its crystal structure. Therefore, confirming the crystal structure of H-CuCo using conventional methods is virtually impossible.

[0082] Emerging three-dimensional (3D) electron diffraction (ED) is considered a powerful method for structure determination. 2-5 A specific method from rotating electron diffraction (RED) has been used to resolve the initial structural models from various functional crystalline materials. 2,6 Specifically, sustained RED (cRED) can collect hundreds of ED spectra in a short time (<5 minutes) and at a low electron dose rate. 7-8 This allows cRED to not only resolve initial structural models, but also to refine certain crystalline materials.

[0083] To accurately confirm the structure of H-CuCo, cRED was used to resolve its crystal lattice. The PBA unit cell parameters of hexagonal CuCo were derived using cRED. (α = 90.52°, β = 89.70°, and γ = 119.53°). (Reference) Figure 3B The reflection condition obtained from the two-dimensional slice cut from the three-dimensional reciprocal lattice is h-hl:l=2n, thus yielding three possible space groups: P63cm (number 185), P-6c2 (number 188), and P63 / mcm (number 193).

[0084] The cRED data were further processed, and intensities were extracted using X-ray detector software (XDS). Ab initio structural analysis was performed using the highest space group recommended by SHELXT for initial structural analysis, via a direct method embedded in SHELXT. 9 Within a single unit cell, there are six Cu ions, four Co ions, and twenty-four cyano groups. Each Cu ion is coordinated with four cyano groups to exhibit a planar quadrilateral configuration, while each Co ion is connected with six cyano groups to exhibit an octahedral configuration, unlike a conventional cubic lattice. In this case, the octahedrons and quadrilaterals are connected by alternately sharing cyano groups. This creates a 12-ring channel (considering only metal ions) along the c-axis.

[0085] Atomic environment of elements in Example 4-H-CuCo

[0086] Perform XPS, and the results are shown in Figure 3C-3D In the middle. For example Figure 3D As shown, the entire XPS spectrum of H-CuCo is consistent with the XSP spectrum of the conventional cubic phase C-CuCo, indicating that the composition of Cu, Co, C, and N is the same. Specifically, regarding the Co element in H-CuCo and C-CuCo, Figure 3C The absence of satellite peaks in Co-C≡N is shown. III Corresponding XPS-like graphs 10-11 Furthermore, compared to C-CuCo, the energy of Co in H-CuCo is slightly shifted towards lower energies. This difference can be attributed to variations in the number of adjacent atoms or differences in crystal structure. I and Cu II Both exist in C-CuCo and H-CuCo. However, Cu is clearly observed in H-CuCo. I Cu I :Cu II The ratio is 1.00:1.50, which contrasts with the 1:14.15 ratio observed in C-CuCo. This indicates a significant amount of Cu. II Reduced to Cu I Furthermore, a similar redshift is also observed in H-CuCo. Therefore, the cell composition of its framework under negative charge should be [Cu... + 0.6 Cu 2+ 0.9 Co 3+ 1(CN)6] 0.6- Notably, protonated dimethylamine (PDs) exists as a counter ion, a fact confirmed by 1H nuclear magnetic resonance (NMR). Figure 4A ) and thermogravimetric analysis (TGA) results ( Figure 4B This has been confirmed.

[0087] To further determine the location of PDs, the Rietveld refinement method for PXRD data was employed. An initial structural model of the CuCo prism derived from cRED data analysis was used, and the Rietveld refinement ultimately yielded a convergence rate of 1.86%. wp The goodness-of-fit (GOF) of 2.2 indicates that 2.4PD is distributed within the 12 ring channels of each unit cell, thereby balancing the negative charge from the framework.

[0088] like Figures 5A-5B As shown, the SEM image reveals the hexagonal prism morphology of H-CuCo. [Go to...] Figure 5CTEM images of H-CuCo also show a hexagonal prism morphology, revealing that the prisms are approximately 125 nm x 400 nm in size. For comparison, SEM images of conventional cubic CuCo PBA... Figure 5D ) and TEM Figure 5E The image shows a cubic shape with a size of approximately 180nm*180nm.

[0089] refer to Figure 5F This displays the corresponding selected region electron diffraction (SAED) pattern along the [1-10] zone axis. This pattern is fitted to the hexagonal phase of PBA, rather than the conventional face-centered cubic (fcc) phase. From Figure 5C Captured in the white box marked in the middle Figure 5G The image shows a high-resolution transmission electron microscopy (HRTEM) image. The image shows a lattice fringe spacing of approximately 1.40 nm.

[0090] Figure 5H It shows Side view of the H-CuCo lattice. Image plotted using HAADF-STEM elements. Figure 5I It can be observed that the elemental distribution of Cu, Co, C, and N in H-CuCo is uniform. Energy-dispersive X-ray spectroscopy (EDS) confirmed that the chemical compositions of Cu, Co, C, and N in H-CuCo and C-CuCo are similar, such as... Figures 6A-6B As shown.

[0091] Example 5 - Extended Synthesis

[0092] To extend the novel hexagonal CuCo PBA, Co, Fe, Ni, and Zn were doped into the synthesis (denoted as Co). 0.1 -CuCo, Fe 0.1 -CuCo, Fe 0.2 -CuCo, Ni 0.1 -CuCo and Zn 0.1 -CuCo).

[0093] Synthesis of hexagonal phase Co 0.1 -CuCo PBA

[0094] 5 mL of deionized water containing 0.2 mmol CuCl₂·2H₂O, 0.02 mmol CoCl₂·6H₂O, and 0.2 mmol sodium citrate was added to a mixed solution containing 5 mL of deionized water and 25 mL of DMF, in which 0.2 mmol K₃Co(CN)₆ and 0.2 g PVP were dissolved. The solution was then stirred continuously in a 30°C water bath for 48 hours. After the reaction was complete, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. Finally, the collected sample was dried in an oven at 80°C for 12 hours.

[0095] Synthesis of hexagonal phase Fe 0.1 -CuCo PBA

[0096] 5 mL of deionized water containing 0.2 mmol CuCl₂·2H₂O, 0.02 mmol FeCl₃·6H₂O, and 0.2 mmol sodium citrate was added to a mixed solution containing 5 mL of deionized water and 25 mL of DMF, in which 0.2 mmol K₃Co(CN)₆ and 0.2 g PVP were dissolved. The solution was then stirred continuously in a 30°C water bath for 48 hours. After the reaction was complete, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. Finally, the collected sample was dried in an oven at 80°C for 12 hours.

[0097] Synthesis of hexagonal phase Fe 0.2 -CuCo PBA

[0098] 5 mL of deionized water containing 0.2 mmol CuCl₂·2H₂O, 0.04 mmol FeCl₃·6H₂O, and 0.2 mmol sodium citrate was added to a mixed solution containing 5 mL of deionized water and 25 mL of DMF, in which 0.2 mmol K₃Co(CN)₆ and 0.2 g PVP were dissolved. The solution was then stirred continuously in a 30°C water bath for 48 hours. After the reaction was complete, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. Finally, the collected sample was dried in an oven at 80°C for 12 hours.

[0099] Synthesis of hexagonal phase Ni 0.1 -CuCo PBA

[0100] 5 mL of deionized water containing 0.2 mmol CuCl₂·2H₂O, 0.04 mmol NiCl₂·6H₂O, and 0.2 mmol sodium citrate was added to a mixed solution containing 5 mL of deionized water and 25 mL of DMF, in which 0.2 mmol K₃Co(CN)₆ and 0.2 g PVP were dissolved. The solution was then stirred continuously in a 30 °C water bath for 48 hours. After the reaction was complete, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. Finally, the collected sample was dried in an oven at 80 °C for 12 hours.

[0101] Synthesis of hexagonal Zn 0.1 -CuCo PBA

[0102] 5 mL of deionized water containing 0.2 mmol CuCl₂·2H₂O, 0.02 mmol ZnCl₂, and 0.2 mmol sodium citrate was added to a mixed solution containing 5 mL of deionized water and 25 mL of DMF, in which 0.2 mmol K₃Co(CN)₆ and 0.2 g PVP were dissolved. The solution was then stirred continuously in a 30°C water bath for 48 hours. After the reaction was complete, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. Finally, the collected sample was dried in an oven at 80°C for 12 hours.

[0103] like Figures 7A-7D As shown, after continuous doping with different transition metal elements under various synthesis conditions, the morphology of hexagonal PBA changed from hexagonal prisms to two-dimensional plates and columns. A series of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images and corresponding elemental plots show that dopant atoms were successfully introduced into CuCo PBA. This indicates that dopant atoms can significantly affect the morphology. Although the morphology changed significantly, its XRD pattern shows that the doped material still retains the hexagonal phase.

[0104] To further investigate the effect of dopant atoms, XPS analysis was performed on the Cu element content of these five doped materials. Figure 8 XPS spectra reveal that Cu i Cu 2+ The ratios differ; compared to H-CuCo, Fe... 0.1 -CuCo, Fe 0.2 -CuCo, Ni 0.1 -CuCo and Zn 0.1 -CuCo contains Cu I The ratio increased significantly. Meanwhile, in Co- 0.1 In CuCo, Cu IThe ratio decreases. This indicates that the amount of unsaturated Cu atoms can be controlled by introducing different dopant metal atoms.

[0105] Furthermore, it was found that dopant atoms may affect the unsaturated copper content in hexagonal CuCo PBA. For example, Ni, Fe, and Zn increase the unsaturated copper content in Cu. I The content of Cu is reduced, while materials doped with Co reduce Cu content. I The content of Co. Therefore, based on the XPS results and inductively coupled plasma (ICP) results (Table 1) of the Cu:Co ratio, it is concluded that for Co... 0.1 -CuCo, Fe 0.1 -CuCo, Fe 0.2 -CuCo, Ni 0.1 -CuCo and Zn 0.1 -CuCo, the molecular formula of the dopant CuCo PBA should be [Co 2+ 0.16 Cu + 0.41 Cu 2+ 0.93 Co 3+ 0.84 (CN)6] 0.89- 、[Fe 3+ 0.02 Cu + 1.32 Cu 2+ 0..44 Co 3+ 1(CN)6] 0.74- 、[Fe 3+ 0.03 Cu + 1.25 Cu 2+ 0.42 Co 3+ 1(CN)6] 0.82- 、[Ni 2+ 0.06 Cu + 1.12 Cu 2+ 0.48 Co 3+ 1(CN)6] 0.8- 、[Zn 2+ 0.21 Cu + 1.09 Cu 2+ 0.38 Co 3+ 1(CN)6] 0.73- .

[0106] Table 1 - Based on H-CuCo, Co0.1 -CuCo, Fe 0.1 -CuCo, Fe 0.2- CuCo, Ni 0.1 -CuCo and Zn 0.1 - Cu:Co atomic ratio from ICP results Material Cu Co C-CuCo 1.40 1 H-CuCo 1.50 1 Co 0.1 -CuCo 1.34 1 Ni 0.1 -CuCo 1.57 1 Fe 0.1 -CuCo 1.76 1 Fe 0.2 -CuCo 1.67 1 <![CDATA[Zn 0.1 -CuCo]]> 1.47 1

[0107] Example 6 - Gas intake and separation performance

[0108] To determine the permanent porosity after solvent removal, Brunauer-Emmett-Teller (BET) nitrogen adsorption experiments were performed at 77 K. BET nitrogen adsorption is a common experimental method used for surface area measurement and pore structure analysis. This technique involves adsorbing nitrogen onto the surface of a material under various pressures to determine its specific surface area and pore structure. By measuring the amount of nitrogen adsorbed on the material surface as a function of adsorption pressure, parameters such as specific surface area, pore volume, and pore size distribution can be calculated, providing valuable insights into the pore structure characteristics of the material.

[0109] Prior to the BET experiment, H-CuCo and C-CuCo were treated in vacuum at 100°C, and XRD patterns before and after treatment were collected. (Reference) Figure 9 The XRD patterns of C-CuCo before and after treatment were almost identical. However, for H-CuCo, the peak at 17.6° disappeared after drying. This is likely due to gas degassing. Additionally, H-CuCo was observed to be purple after being dried and degassed in a vacuum, turning blue upon exposure to air, indicating that H-CuCo has a stable structure.

[0110] BET Figure 10A The figure of 1273.244 m for H-CuCo, calculated by DFT, is shown. 2 g -1 The surface area, which is 443.416m 2 g -1 The surface area contrasts significantly. Compared to other conventional PBAs, H-CuCo has a much larger surface area, exceeding 900 μm. 2 / g, while other PBA reports show surface areas below 900m². 2 / g. Additionally... Figure 10B It is shown that H-CuCo has three types of pores, and the half-pore width of the three types of pores is... and This resulted in 0.800cm 3 g -1The total pore volume. This contrasts with C-CuCo, which has a type of pore with a certain half-pore width and a pore volume of 0.217 cm³. 3 g -1 .

[0111] Below are the adsorption isotherms of single-component gases (CO2, CH4, C2H2, C2H4, C2H6, C3H6, and C3H8) of H-CuCo PBA and C-CuCo PBA, taken from 273 K to 298 K. Figure 10C (and Table 2).

[0112] Table 2 - H-CuCo, C-CuCo, Fe 0.1 -CuCo, Fe 0.2 -CuCo and Co 0.1 -CuCo gas adsorption properties

[0113] Specifically, H-CuCo exhibits a CO2 uptake of 136.41 cm³ at 273 K and 1 bar. 3 g -1 (6.09mmol g -1 This indicates that one H-CuCo molecule captures 8.2 CO2 molecules. At 298 K and 1 bar, the CO2 uptake of H-CuCo is 93.65 cm⁻¹. 3 g -1 (4.18mmol g -1 These two CO2 uptake values ​​exceed those of C-CuCo at 273K and 298K under 1 bar conditions, respectively, at 89.57 cm⁻¹. 3 / g and 69.87cm 3 / g (4.00mmol / g and 3.12mmol / g).

[0114] For CH4, C2H2, C2H4, C2H6, C3H6, and C3H8, under the same conditions, H-CuCo exhibited an uptake capacity more than 1.5 times that of C-CuCo, demonstrating superior adsorption performance. This indicates that hexagonal CuCo PBA has a better gas uptake capacity than the conventional cubic phase of CuCo PBA. Table 3 also shows that H-CuCo's CO2 adsorption capacity is among the best compared to previously reported materials.

[0115] Table 3 - Selected Examples of CO2 Storage Unless otherwise specified, the surface area is calculated using the Bruno-Emmett-Taylor (BET) method. b Unless otherwise stated, CO2 adsorption is measured at 1 bar. The surface area c was measured using the Langmuir method.

[0116] Furthermore, an experimental penetration test was conducted on C3H6 / C2H4 (50 / 50, v / v) at 273 K. (Reference) Figure 11 For H-CuCo PBA, C2H4 breakthrough occurred at 439 s / g, while for C-CuCo PBA, it occurred almost simultaneously at 412 s / g. However, the retention time of C3H6 in the packed column for H-CuCo was 779 s / g, which is longer than the 670 s / g retention time for C-CuCo. The separation coefficient of H-CuCo for C3H6 and C2H4 was 6.82, twice that of C-CuCo, whose separation coefficient was 3.35.

[0117] refer to Figure 12 Unlike C-CuCo, which did not exhibit separation behavior for CO2 / CH4, H-CuCo showed potential CO2 / CH4 separation behavior, representing a significant breakthrough. These results demonstrate that phase engineering provides a new and promising strategy for gas capture and separation.

[0118] To further explore the gas trapping performance of the dopant CuCo PBA, a series of BET and single-shot gas uptake measurements were performed (Table 4 and...). Figures 13A-13H ).

[0119] Table 4 - Surface Area of ​​PBA

[0120] Compared to Co0.1-CuCo, Fe0.1-CuCo exhibits a higher specific surface area and better gas capture performance. This indicates that unsaturated active atoms enhance the storage capacity of small molecule gases. Furthermore, the results show that doped CuCo PBA significantly improves the gas uptake performance for gases such as C2H4 and C2H6. However, excessively high doping rates lead to lower specific surface area and gas uptake performance.

[0121] Example 7 - Mechanism

[0122] To investigate the reasons for the enhanced properties of H-CuCo, XAFS measurements were performed to evaluate the local electronic structure and geometry of the metal elements in the thus prepared H-CuCo. The K-edge X-ray absorption near-edge structures (XANES) of Co in H-CuCo, C-CuCo, and K3Co(CN)6 are shown in the figure. Figure 14A The similarity curves of the XANES spectra of Co further confirm that H-CuCo belongs to the PBA family. In addition, the fully overlapping edge-front XANES spectra of Co show that the Co element in H-CuCo, C-CuCo and K3Co(CN)6 has the same valence state and Co-C≡N environment.

[0123] In the corresponding Fourier transform X-ray absorption fine structure (FT-EXAFS) of the K-side of Co ( Figure 14B ), located in R space and The peaks at that location should be attributed to Co-C, Co-C≡N, and Co-C≡N-Cu scattering, respectively.

[0124] Additionally, EXAFS based on Co-C and Co-C≡N ( Figure 14C The wavelet transform (WT) intensities of H-CuCo, C-CuCo, and K3Co(CN)6 indicate that H-CuCo, C-CuCo, and K3Co(CN)6 have the same coordination number for Co-C and Co-C≡N. However, for Co, the intensity of Co-C≡N-Cu in H-CuCo in both WT and FT-EXAFS is significantly lower than that of C-CoCu in C-CuCo, suggesting a lower coordination number for Co-C≡N-Cu in H-CuCo.

[0125] Furthermore, Cu K-edge XANES of H-CuCo, C-CuCo, Cu2O, CuO, and CuPc were tested. The highly similar absorption energies and white-line peak shapes of H-CuCo and C-CuCo in the XANES further confirm that H-CuCo belongs to the PBA material, while its characteristics differ considerably from those of CuPc, CuO, and Cu2O references due to the different Cu-N≡C atomic environment in PBA. The edge-front absorption energy of H-CuCo shifts slightly to lower energies, indicating that Cu in H-CuCo has a lower valence state. In addition, based on the edge-front curve of CuPc, the slightly higher edge-front peak of H-CuCo at approximately 8987 eV for Cu elemental analysis suggests that it has a more planar quadrilateral configuration than C-CuCo.

[0126] In the FT-EXAFS of Cu, the R-space contains... and The peak at that location should be attributed to Cu-N and Cu-N≡C scattering, similar to CuPc. The Cu-N intensity is the same for H-CuCo and C-CuCo, while the Cu-N≡C intensity is slightly lower for H-CuCo than for C-CuCo, due to the more planar configuration of Cu atoms. For The peak at that point should be represented as Cu-N≡C-Co, and a similar situation, where the Cu-N≡C-Co bond exhibits significantly lower intensity in H-CuCo, is characterized by the FT-EXAFS of Co. These features are also confirmed by wavelet transform. Figure 14D Then, after fitting and calculation using FT-EXAFS for Co and Cu ( Figures 15A-15D The detailed coordination numbers of H-CuCo and C-CuCo are listed in Table 5.

[0127] Table 5 - EXAFS Fitting Results

[0128] The results show that the coordination numbers of Co-C and Co-C≡N are the same for both H-CuCo and C-CuCo. However, the coordination numbers of Cu-N and Cu-N≡C in H-CuCo are lower than those in C-CuCo, which is due to the presence of some unsaturated Cu and the formation of a planar configuration, consistent with the above analysis.

[0129] The presence of open metal sites contributes to improved adsorption capacity and separation selectivity. Therefore, the superior gas adsorption and separation performance stems not only from the higher specific surface area but also from the abundance of Cu-N≡C planar configurations. These planar configurations provide open and unsaturated Cu atoms with low valence for coordination with gas molecules. This beneficial effect is attributed to the novel hexagonal phase of H-CuCo.

[0130] Industrial applicability

[0131] Hexagonal H-CuCo PBA and its doped derivatives are widely used in various fields due to their unique properties, such as gas storage and separation, electrochemical biosensors, photothermal therapy, catalysis, nanozymes, drug delivery systems, radioactive ion removal, energy storage devices, and water desalination technology.

[0132] definition

[0133] Throughout this specification, unless the context otherwise requires, the word “comprise” or variations such as “comprises” or “comprising” should be understood to imply inclusion of the stated whole or group of wholes, but not to exclude any other whole or group of wholes. It should also be noted that in this disclosure and particularly in the claims and / or paragraphs, terms such as “comprises,” “comprised,” and “comprising” may have the meaning attributed to them under U.S. patent law, for example, allowing for elements not expressly listed but excluding elements found in the prior art or affecting the essential or novel features of the invention.

[0134] Furthermore, throughout this specification and claims, unless the context otherwise requires, the word "include" or variations thereof, such as "includes" or "including," shall be understood to imply inclusion of the stated whole or group of wholes, but not to exclude any other whole or group of wholes.

[0135] As used herein and unless otherwise defined, the terms “substantially,” “basically,” “approximately,” and “about” are used to describe and explain small variations. When used in conjunction with an event or situation, the terms may cover instances where the event or situation occurs precisely or instances where the event or situation is close to occurring. For example, when used in conjunction with a numerical value, the terms may cover a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

[0136] References to "an embodiment," "an example embodiment," "exemplary embodiment," etc., in this specification indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is assumed that the effect of such feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art, whether explicitly described or not.

[0137] In the preparation methods described herein, steps may be performed in any order without departing from the principles of the invention, except where the timing or order of operations is explicitly stated. A statement in a claim that implies performing a step first, followed by several other steps, should be interpreted as meaning that the first step is performed before any other steps, but the other steps may be performed in any suitable order unless the order is further stated in the other steps. For example, a claim element stating "steps A, B, C, D, and E" should be interpreted as meaning that step A is performed first, and step E is performed last, and steps B, C, and D may be performed in any order between steps A and E, and such order still falls within the literal scope of the claimed process. A given step or subset of steps may also be repeated. Furthermore, unless the steps specified in the explicit claim language are performed separately, the specified steps may be performed simultaneously.

[0138] Cu I "and "Cu II "Cu" refers to the different oxidation states of copper. I "" indicates the +1 oxidation state of copper (copper(I) or cuprous), while "Cu" indicates the +1 oxidation state of copper. II " " indicates the +2 oxidation state of (copper(II) or cuprous).

[0139] Other definitions of the selected terms used herein can be found in the specific embodiments of the invention and apply throughout. Unless otherwise defined, all other technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0140] References 1. Pal, SC, Krishna, R., & Das, MC (2023). Highly scalable acid-base resistant Cu-Prussian blue metal-organic framework for C2H2 / C2H4, biogas, and flue gas separations. Chemical Engineering Journal, 460, 141795. 2. Zhang, D.; Oleynikov, P.; S.; Zou, X., Collecting 3D electron diffraction data by the rotation method. Journal of Crystallography (Z. Kristallogr.) 2010, 225(2-3), 94-102. 3. Shi, D.; Nannenga, BL; Iadanza, MG; Goren, T., Three-dimensional electron crystallography of protein microcrystals. Elife Journal, 2013, 2, e01345. 4. Nannenga, BL; Shi, D.; Leslie, AGW; Goren, T., High-resolution structure determination by continuous-rotation data collection in MicroED. Nature Methods, 2014, 11(9), 927-930. 5. Kolb, U.; Gorelik, T.; Kubel, C.; Otten, MT; Hubert, D., Towards automated diffraction tomography: part I--data acquisition. Ultramicroscopy, 2007, 107(6-7), 507-13. 6. Wan, W.; Sun, J.; Su, J.; Hovmoller, S.; Zou, X., Three-dimensional rotation electron diffraction: software RED for automated data collection and data processing. Journal of Applied Crystallography, 2013, 46(Pt 6), 1863-1873. 7. Cichocka, MO; J.; Wang, B.; Zou, X.; Smeets, S., High-throughput continuous rotation electron diffraction data acquisition via software automation. Journal of Applied Crystallography, 2018, 51(Pt 6), 1652-1661. 8. Wang, Y.; Takki, S.; Cheung, O.; Xu, H.; Wan, W.; Ohrstrom, L.; Inge, AK. Elucidation of the elusive structure and formula of the active pharmaceutical ingredient bismuth subgallate by continuous rotation electron diffraction. Chem. Communications, 2017, 53(52), 7018-7021. 9. Sheldrick, GM, SHELXT - integrated space-group and crystal-structure determination. Acta Crystallography, A 2015, 71(1), 3-8. 10. Oku, M.; Hirokawa, K., X-ray photoelectron spectroscopy of Co3O4, Fe3O4, Mn3O4 and related compounds. Journal of Electron Spectroscopy and Related Phenomena, 1976, 8(5), 475-481. 11. Oku, M.; Hirokawa, K.; Ikeda, S., Photoelectron spectral intensities of some first transition series elements in metal cyanides containing inequivalent atoms. Journal of Electron Spectroscopy and Related Phenomena, 1975, 6(5), 451-458.

Claims

1. A hexagonal copper-cobalt Prussian blue analog material, characterized in that, The hexagonal copper-cobalt Prussian blue analog material comprises: 30-40 wt% copper; 10-30 wt% cobalt; 10-30 wt% carbon; and 10-30 wt% nitrogen, Each copper ion is coordinated with four cyano groups to exhibit a planar quadrilateral configuration, while each copper ion is connected with six cyano groups to exhibit an octahedral configuration.

2. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein the hexagonal copper-cobalt Prussian blue analog material is capable of forming prism-shaped crystals.

3. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein the 2θ values ​​of the hexagonal copper-cobalt Prussian blue analog material are 13.9°, 14.4°, 16.0°, 20.1°, 21.7°, 22.1°, 23.2°, 25.1°, 25.5°, 26.2°, 29.1°, 29.9°, 31.1°, 32.4°, and 36.1°. 37.1°, 37.9°, 38.8°, 39.5°, 40.8°, 41.7°, 44.9°, 45.8°, 46.2°, 47.1°, 50.2°, 51.6°, 52.4°, 53.2°, 53.9°, 55.3°, 57.5°, 57.8°, 58.9°, 61.2°, 61.7°, 62.9°, 64.0°.

4. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein the hexagonal copper-cobalt Prussian blue analog material exhibits a hexagonal lattice structure.

5. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein the surface area of ​​the hexagonal copper-cobalt Prussian blue analog material is at least 1000 m². 2 g -1 .

6. The hexagonal copper-cobalt-Prussian blue analog material according to claim 1, wherein the hexagonal copper-cobalt-Prussian blue analog material has larger channels and interstitial spaces for storage and diffusion of metal ions, etc.

7. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein the hexagonal copper-cobalt Prussian blue analog material exhibits three types of pores, the half-pore width of the three types of pores being [missing information]. and 8. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein there are numerous unsaturated copper sites within the framework of the hexagonal copper-cobalt.

9. The hexagonal copper-cobalt Prussian blue analog material according to claim 8, wherein the hexagonal copper-cobalt Prussian blue analog material exhibits a large number of Cu... I And Cu-N≡C-Co with low coordination number.

10. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein the hexagonal copper-cobalt Prussian blue analog material exhibits gas adsorption properties, said gas adsorption properties being at least 1.5 times that of the gas adsorption properties of the cubic Prussian blue analog material.

11. The hexagonal copper-cobalt Prussian blue analog material according to claim 10, wherein the gas comprises CO2, CH4, C2H2, C2H4, C2H6, C3H6 and C3H8.

12. The hexagonal copper-cobalt Prussian blue analog material according to claim 1, wherein the hexagonal copper-cobalt Prussian blue analog material exhibits superior separation performance for C3H6 / C2H4 and CO2 / CH4 compared to the cubic Prussian blue analog material.

13. The hexagonal copper-cobalt-Prussian blue analog material according to claim 1, wherein the hexagonal copper-cobalt-Prussian blue analog material is further doped with one or more metal precursors.

14. The hexagonal copper-cobalt Prussian blue analog material according to claim 13, wherein the one or more metal precursors comprise FeCl3, NiCl2, or ZnCl2 or their hydrates.

15. A method for synthesizing hexagonal copper-cobalt Prussian blue analogues, characterized in that, The method includes: Deionized water containing CuCl2·2H2O and sodium citrate is added to a mixed solution of deionized water and dimethylformamide containing K3Co(CN)6 and polyvinylpyrrolidone to obtain a first solution. The first solution was stirred continuously in a 30°C water bath for 24-48 hours; Centrifuge the first solution and collect the precipitate; The collected precipitate was rinsed at least three times with the deionized water and ethanol. as well as Dry the collected samples at 80°C for 10-15 hours.

16. The method of claim 15, wherein the method does not require high-temperature treatment or any other post-processing.

17. The method of claim 15, wherein the hexagonal copper-cobalt Prussian blue analogue material is capable of forming prism-shaped crystals.

18. The method of claim 15, wherein the first solution further comprises one or more metal precursors.

19. The method of claim 18, wherein the one or more metal precursors comprise FeCl3, NiCl2, or ZnCl2 or their hydrates.

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