Controllable synthesis method of nickel phosphide micro-nano material

[0031] Example 1

[0032] Synthesis of Ni by Changing the Phosphorus-Nickel Ratio 2 P or Ni 12 P 5 : select the P/Ni molar ratio to be 1//1, 2/1, 4/1, 6/1, 8/1 respectively for hydrothermal synthesis. It is only described when the P/Ni molar ratio is 6. Put 10.9009g (0.0375 moL) of nickel nitrate and 50mL of distilled water into a 100mL beaker, stir well until the solution is clear, then add 6.975g (0.225moL) of fully ground red phosphorus. Put the beaker in a water bath with electromagnetic stirring at 60°C for aging for 2 hours, then transfer the suspension into a 100mL polytetrafluoroethylene-lined autoclave, seal it, and place it in a constant temperature drying oven at 120°C for 12 hours. No surfactant was added in the experiment. After the reaction, the reactor was taken out and cooled to room temperature naturally. The black solid matter in the autoclave was collected, and centrifuged and washed with hot ethanol and distilled water in order to remove unreacted inorganic substances doped in the product, and finally the obtained product was vacuum-dried at 60°C for 12 hours.

[0033] figure 1 X-ray powder diffraction (XRD) spectra of synthesized products with different phosphorus-nickel molar ratios. Depend on figure 1 It can be seen that when the initial n(P)/n(Ni)=1/1 and 2/1, at 2θ=8.1 o , 14.0 o , 19.9 o , 24.4 o , 28.2 o , 32.8 o The series of diffraction peaks appearing at can be attributed to Ni 11 (HPO 3 ) 8 (OH) 6 (PDF44-1327), the product is a basic salt of phosphorous acid. When the initial n(P)/n(Ni)=4/1, at 2θ=32.7 o , 35.8 o , 38.4 o , 41.7 o , 44.4 o , 47.0 o , 49.0 o Appeared Ni 12 P 5 The characteristic diffraction peaks (PDF22-1190). When the initial phosphorus-nickel molar ratio increases to n(P)/n(Ni)=6/1 and 8/1, at 2θ=40.8 o , 44.6 o , 47.3 o , 54.4 0 appears Ni 2 The characteristic diffraction peak of the P phase (PDF03-0953), and the baseline is relatively flat, without any impurity peaks, indicating that the pure hexagonal nickel phosphide (Ni 2 P). This embodiment illustrates that the initial phosphorus-nickel molar ratio has a greater impact on the phase of the product, and cannot synthesize nickel phosphide when the amount of red phosphorus is small; the increase in the phosphorus-nickel ratio helps to synthesize the product from Ni 12 P 5 to you 2 P transformation, if you want to realize Ni 2 For the controlled synthesis of P, the minimum molar ratio of n(P)/n(Ni) should be 6/1.

[0034] Example 2

[0035] Synthesis of Ni by changing the hydrothermal temperature 12 P 5 : Put 10.9009g of nickel nitrate (0.0375mol) and 50ml of distilled water into a 100ml beaker, stir well until the solution becomes clear, then add 4.65g (0.15mol) of fully ground red phosphorus. The hydrothermal reaction temperature was set at 90 o C. 120 o C. 150 o C and 180 o C, the reaction time is 12h, the solvent is water, and no surfactant is added. All the other operating steps are the same as in Example 1.

[0036] figure 2 X-ray powder diffraction (XRD) spectra of synthesized products at different temperatures when n(P)/n(Ni)=4. It can be seen from the figure that when P/Ni=4, the reaction temperature is 90 o C, at 2θ=32.7 o , 35.8 o , 38.4 o , 41.7 o , 44.4 o , 47.0 o , 49.0 o The series of diffraction peaks that appear are attributed to Ni 12 P 5 (PDF22-1190), showing that the resulting product is mainly Ni 12 P 5 , but there are still many impurity peaks in the resulting spectrum, indicating that the hydrothermal reaction is not complete at this time. When the temperature gradually rises to 120 o At C and 150°C, the impurity peaks become smaller and smaller, and the Ni 12 P 5 The peak becomes stronger and stronger, and the product obtained at 150°C is relatively pure tetragonal Ni 12 P 5; when the temperature is 180 o C, at 2θ=8.1, 14.0 o , 19.9 o , 24.4 o , 28.2 o , 32.8 o The series of diffraction peaks appearing at can be attributed to Ni 11 (HPO 3 ) 8 (OH) 6 , the product is a basic salt of phosphorous acid, indicating that as the temperature increases, Ni 12 P 5 Most of them have been transformed into Ni 11 (HPO 3 ) 8 (OH) 6.

[0037] image 3 It is the Ni obtained when n(P)/n(Ni)=4 at 120°C for 12 hours 12 P 5 Scanning Electron Microscope (SEM) image. It can be seen from the figure that Ni 12 P 5 It is formed by the dense accumulation of a large number of spherical particles. The diameter of the spherical particles is about 100nm, and some holes of different sizes are surrounded by the spherical particles.

[0038] Example 3

[0039] Synthesis of Ni by changing the hydrothermal temperature 12 P 5 or Ni 2 P: Put 10.9009g of nickel nitrate (0.0375mol) and 50ml of distilled water in a 100ml beaker, stir well until the solution becomes clear, then add 9.3g (0.3mol) of fully ground red phosphorus. The hydrothermal reaction temperature was set at 90 o C. 120 o C. 150 o C and 180 o C, the reaction time is 12h, the solvent is water, and no surfactant is added. All the other operating steps are the same as in Example 1.

[0040] Figure 4 X-ray powder diffraction (XRD) spectra of synthesized products at different temperatures when n(P)/n(Ni)=8. It can be seen from the figure that when the reaction temperature is 90 o C, at 2θ=40.8 o , 44.6 o , 47.3 o , 54.4 0 The characteristic diffraction peaks appearing at can be attributed to Ni 2P(PDF03-0953), the peak intensity is larger, but at 2θ=38.4 o , 49.0 o There is also a characteristic diffraction peak with low intensity, which can be attributed to Ni 12 P 5 (PDF22-1190), indicating that the hydrothermal reaction product at this temperature is mainly Ni 2 P, with a small amount of Ni 12 P 5. When the temperature is 120 o C, at 2θ=40.8 o , 44.6 o , 47.3 o , 54.4 0 The characteristic diffraction peaks appearing at can be attributed to Ni 2 P, the peak is sharper, indicating that the crystallinity is higher, and the product purity is very high, and the obtained product is pure hexagonal phase structure Ni 2 p. When the temperature is 150 o C, at 2θ=32.7 o , 35.8 o , 38.4 o , 41.7 o , 44.4 o , 47.0 o , 49.0 o The series of diffraction peaks that appear are attributed to Ni 12 P 5 , but at 2θ=40.8 o Trace Ni 2 The P peak exists, that is, the obtained product except the tetragonal Ni 12 P 5 In addition, there is a trace amount of Ni 2 p. When the temperature is 180 o At C, the peak position of the XRD pattern is the same as that at 150 o C is the same, but the intensity of the diffraction peaks of different crystal planes changes slightly, and the obtained product is pure tetragonal Ni 12 P 5 , no other impurities are generated, and the product has a high purity. This example shows that by changing the hydrothermal reaction temperature, the phase state controllable synthesis of nickel phosphide can be realized, and the temperature rise is beneficial to Ni 2 P to Ni 12 P 5 change.

[0041] Figure 5 It is the Ni obtained when n(P)/n(Ni)=8 at 120°C for 12h 2 Scanning electron microscope (SEM) image of P. It can be seen from the figure that Ni 2 The morphology of P is a large number of spherical particles, which are densely packed with each other. The diameter of the spherical particles is about 80nm, and some holes of different sizes are surrounded by the spherical particles.