Cerium-manganese solid solution oxide material, preparation method thereof and application of cerium-manganese solid solution oxide material in photoinduced compatibilization

Abstract

The invention discloses a cerium-manganese solid solution oxide material, a preparation method thereof and application of the cerium-manganese solid solution oxide material in photoinduced compatibilization, and belongs to the technical field of inorganic non-metallic material preparation and new energy. The bimetallic oxide with the grain size at the nanometer level can be obtained through a designed uniform precipitation method, the cerium-manganese oxide material is of a cubic fluorite phase crystal structure, cerium and manganese ions occupy the same lattice position and are in a solid solution state, and compared with a pure-phase cerium dioxide material, the electrochemical property of the cerium-manganese oxide material is remarkably improved; and meanwhile, the defects of low specific capacitance and low charge transfer efficiency of the traditional cerium dioxide as an electrode material are overcome, and the material is applied to the field of supercapacitors as a photoresponsive electrode material.

Description

Technical Field

[0001] The invention relates to the field of inorganic non-metallic material preparation and new energy technology, and in particular to a cerium-manganese solid solution oxide material and a preparation method thereof and application in photocompatibilization. Background Art

[0002] Cerium (Ce) is the most abundant rare earth element in the earth's crust, accounting for about 0.0046wt% of the earth's crust. It is used in many fields such as magnetism, phosphors, alloys and catalysis. China has rich mineral resources and has been the world's largest producer of rare earths for more than a decade, accounting for more than 90% of global production. 2 ) usually exists in the form of cubic fluorite phase, with a face-centered cubic crystal structure. Each cerium ion is coordinated with 8 oxygen ions, and the electronic structure of cerium makes it 4+ and Ce 3+ Therefore, Ce 3+ The formation of ions is usually accompanied by the presence of oxygen vacancies on the surface and in the bulk. In addition, ceria has obvious mobile oxygen vacancies, which can improve the conductivity and electrochemical properties of the material through electron delocalization around oxygen. Therefore, ceria has been considered to be a promising supercapacitor electrode material, but its low specific capacity limits its practical application.

[0003] Manganese dioxide materials, which also have a tetragonal structure, have attracted much attention because of their ultra-high theoretical specific capacitance, fast charging and discharging capabilities similar to non-Faraday energy storage, simple preparation methods, low prices, and abundant raw materials. However, manganese-based electrodes generally have poor cycle stability due to structural instability and low ion diffusion constants. If the advantages of the two metal elements are combined and solid solution design is performed within the same crystal structure, it will be possible to complement each other's advantages and improve the overall service performance of the electrode material. However, to realize this innovative idea, it is necessary to select a suitable synthesis environment and process path to achieve it, and it is also necessary to design it specifically according to the chemical activity of the metal elements. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a cerium manganese solid solution oxide material and a preparation method thereof and application in photocapacitance. A bimetallic oxide with a grain size at the nanometer level can be obtained by a designed uniform precipitation method. The cerium manganese oxide material has a tetragonal crystal structure, and cerium and manganese ions occupy the same lattice positions, presenting a solid solution state. Compared with pure phase cerium dioxide materials, its electrochemical properties are significantly improved. At the same time, it overcomes the defects of low specific capacitance and low charge transfer efficiency of traditional cerium dioxide as an electrode material, and can be used as a light-responsive electrode material in the field of supercapacitors.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A cerium-manganese solid solution oxide material, the chemical composition expression in terms of atomic ratio is Ce X Mn Y O 2 , where X=0.6-0.9, Y=0.4-0.1, and X+Y=1.

[0007] Furthermore, the cerium-manganese solid solution oxide material has a cubic crystal structure, and the cerium and manganese ions occupy the same lattice positions, presenting a solid solution state.

[0008] Furthermore, the cerium-manganese solid solution oxide material has a grain size of 5-50 nm and exhibits a single cubic fluorite phase.

[0009] Furthermore, the preparation method of the cerium-manganese solid solution oxide material comprises the following steps:

[0010] (1) weighing a certain proportion of cerium acetate and manganese acetate powders at room temperature and adding them into deionized water, dissolving them under stirring to obtain a uniform, clear and transparent mixed solution;

[0011] (2) preparing a sodium hydroxide solution, pouring the mixed solution obtained in step (1) and the sodium hydroxide solution into a sealed inner container in proportion, keeping the poured solution occupying 70-90% of the volume of the inner container, heating to 110-150° C. for uniform precipitation reaction, and keeping the temperature for 20-30 hours;

[0012] (3) filtering the mixture obtained after the reaction in step (2), taking the precipitate, washing the precipitate repeatedly with deionized water and anhydrous ethanol for 5 to 6 times, and then drying the precipitate; the drying temperature is 60 to 90° C., and the insulation time is 12 to 30 hours;

[0013] (4) placing the product after drying in step (3) in a muffle furnace for calcination at a temperature of 500 to 600° C. for a holding time of 3 to 5 hours; the gray-black powder obtained after calcination is the cerium-manganese solid solution oxide material.

[0014] Furthermore, in step (1), the molar ratio of cerium acetate to manganese acetate is (1.5-10):1; and the total concentration of metal ions in the mixed solution is 0.5-2 mol / L.

[0015] Furthermore, in step (2), the concentration of the sodium hydroxide solution is 5 to 7 mol / L.

[0016] Furthermore, in step (2), the volume ratio of the sodium hydroxide solution to the mixed solution is (3-5):1.

[0017] Furthermore, the capacitance value of the cerium manganese solid solution oxide material is increased by more than 50% compared with commercial cerium dioxide, and under illumination conditions, light energy can be captured to obtain a higher capacitance value; the cerium manganese solid solution oxide material is used in the preparation of supercapacitors.

[0018] Furthermore, the lighting conditions include sunlight, ultraviolet light, visible light and infrared light.

[0019] The design mechanism and beneficial effects of the present invention are as follows:

[0020] 1, the specific capacitance value of traditional ceria material is lower, and the theoretical specific capacitance value of manganese dioxide is very large, manganese dioxide and ceria material belong to tetragonal phase structure, and the two lattice constants are almost the same, so the two have the possibility of becoming solid solution oxide material. The present invention is by uniformly mixing cerium acetate and manganese acetate raw materials at normal temperatures, using sodium hydroxide as precipitation agent, by controlling raw material proportioning and hydrothermal reaction conditions (such as the high temperature and high pressure environment produced in the hydrothermal reaction) etc., thereby generating trivalent and tetravalent manganese ions and trivalent and tetravalent cerium ions, and in this process part of manganese ions enter into the ceria lattice to form cerium manganese solid solution oxide material, because ceria melting point is very high, and manganese oxide melting point is lower, the present invention carries out the calcination treatment of specific conditions in muffle furnace again, makes remaining manganese ions enter into the ceria lattice to form final cerium manganese solid solution oxide material.

[0021] 2. In the present invention, tetravalent and trivalent manganese ions are doped into the cerium dioxide lattice to form a cerium-manganese solid solution oxide material. Through the interaction between cerium ions and manganese ions and possible redox reactions, the specific capacitance of cerium dioxide is further increased and the electrochemical properties of cerium dioxide are improved.

[0022] 3. In the present invention, the synthesized cerium-manganese solid solution oxide material has fine particles and high purity, which is beneficial to the electrochemical properties of cerium dioxide.

[0023] 4. In the present invention, the raw materials are cheap and simple, the process flow is simple, the operation is easy, and it is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 For Ce 0.6 Mn 0.4 、Ce 0.7 Mn 0.3 、Ce 0.8 Mn 0.2 、Ce 0.9 Mn 0.1 X-ray diffraction pattern of .

[0025] Figure 2 For Ce 0.8 Mn0.2 Physical picture of cerium manganese solid solution oxide material.

[0026] Figure 3 For Ce 0.8 Mn 0.2 Cyclic CV curves at scan rates of 1mV / s, 5mV / s, 10mV / s, 20mV / s, 50mV / s, 100mV / s, and 200mV / s.

[0027] Figure 4 This is a cyclic CV curve diagram of commercial cerium dioxide at scanning speeds of 1mV / s, 5mV / s, 10mV / s, 20mV / s, 50mV / s, 100mV / s, and 200mV / s.

[0028] Figure 5 For Ce 0.6 Mn 0.4 、Ce 0.7 Mn 0.3 、Ce 0.8 Mn 0.2 、Ce 0.9 Mn 0.1 and the photocurrent spectrum of commercial ceria. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and examples, but is not intended to limit the present invention. The preparation of the cerium-manganese solid solution oxide material in the present invention comprises the following steps:

[0030] Under room temperature, cerium acetate and manganese acetate powders in a molar ratio of 10:1 to 6:4 are weighed and dissolved in a certain amount of deionized water, wherein the total concentration of metal ions in the mixed solution is maintained at 0.5 mol / L to 2 mol / L, and the mixed solution is stirred until it becomes clear and transparent, and then a sodium hydroxide solution with a concentration of 5 mol / L to 7 mol / L is prepared.

[0031] Further, a sodium hydroxide solution and a mixed solution with a volume ratio of 3:1 to 5:1 are poured into the inner tank of the hydrothermal kettle, and the solution is kept to account for 70% to 80% of the volume of the inner tank. The lid of the hydrothermal kettle is tightened and the kettle is placed stably in an oven for hydrothermal reaction at a temperature of 110°C to 130°C and a holding time of 23 to 25 hours.

[0032] Furthermore, the product obtained by the hydrothermal reaction is filtered, and the precipitate is taken out, washed with deionized water and anhydrous ethanol for 5 to 6 times, and placed in an oven for drying at a drying temperature of 70° C. to 90° C. for a holding time of 23 to 25 hours.

[0033] Further, the product obtained after drying is placed in a muffle furnace for calcination at a temperature of 500°C to 600°C for 3 to 5 hours. The gray-black powder obtained is the cerium-manganese solid solution oxide material. 0.6 Mn 0.4 、Ce 0.7 Mn 0.3 、Ce 0.8 Mn 0.2 、Ce 0.9 Mn 0.1 The XRD diffraction pattern of Figure 1 shown.

[0034] Example 1

[0035] The cerium-manganese solid solution oxide material prepared in this embodiment is Ce 0.8 Mn 0.2 , the specific process is as follows:

[0036] (1) Weigh 3.81 g of cerium acetate and 0.74 g of manganese acetate (CH 3 COO 2 Mn·4H 2 (2) The powder was dissolved in 15 mL of deionized water and stirred evenly until the mixed solution was clear and transparent, and then 60 mL of sodium hydroxide solution was prepared with a concentration of 6 mol / L;

[0037] (2) Pour the mixed solution and sodium hydroxide solution into the inner tank of the hydrothermal kettle, keep the solution occupying 75% of the volume of the inner tank, tighten the hydrothermal kettle device, and place it steadily in an oven for hydrothermal reaction at a temperature of 120°C for 24 hours.

[0038] (3) After the hydrothermal reaction is completed, the surface liquid is poured off, and the precipitate is taken out and washed with deionized water and anhydrous ethanol for 6 times, and then placed in an oven for drying at 80°C for 24 h.

[0039] (4) Grind the dried sample into powder, put it into a crucible and then calcine it in a muffle furnace at a temperature of 550°C for 4 hours. The gray-black powder obtained is the cerium-manganese solid solution oxide material. The Ce 0.8 Mn 0.2 The grain size of the cerium-manganese solid solution oxide material sample is 6.2 nm, and the purity is greater than or equal to 99.9%.

[0040] The cerium-manganese solid solution oxide material prepared in this embodiment is Ce 0.8 Mn 0.2 , in fact, Figure 2 shown.

[0041] Example 2

[0042] The Ce prepared in Example 1 0.8 Mn 0.2 The CV curve test of cerium manganese solid solution oxide material and commercial cerium dioxide in electrochemical testing is as follows:

[0043] (1) Ce 0.8 Mn 0.2 Cerium manganese solid solution oxide material powder, carbon black and PVDF were mixed uniformly in a weight ratio of 8:1:1 to obtain a mixed powder. 5 mg of the mixed powder was added with 100 ul NMP solution and 5 ul Nafion perfluorinated resin solution. The mixture was ultrasonicated in an ultrasonic machine for 30 min, and the mixture was uniformly coated on the 1×1 mm below the conductive glass. The mixture was placed in an electric hot air drying oven, first dried at 40°C for 24 h, and then dried at 100°C for 2 h to obtain a working electrode. The working electrode was tested using an electrochemical workstation model CHI760E. The scanning speeds of the test were 1 mV / s, 5 mV / s, 10 mV / s, 20 mV / s, 50 mV / s, 100 mV / s, and 200 mV / s. The test results are shown in FIG. Figure 3 The cyclic CV curves are shown.

[0044] (2) As a comparison, commercial cerium dioxide powder, carbon black and PVDF were mixed in a weight ratio of 8:1:1 to obtain a mixed powder. 5 mg of the mixed powder was added with 100 ul of N-methylpyrrolidone solution (NMP) and 5 ul of Nafion perfluorinated resin solution. The mixture was ultrasonicated in an ultrasonic machine for 30 min, and the mixture was evenly coated on the 1×1 mm below the conductive glass. The mixture was placed in an electric hot air drying oven and dried at 40°C for 24 h and then at 100°C for 2 h to obtain a working electrode. The working electrode was tested using a CHI760E electrochemical workstation with scan speeds of 1 mV / s, 5 mV / s, 10 mV / s, 20 mV / s, 50 mV / s, 100 mV / s, and 200 mV / s. The test results were: Figure 4 The cyclic CV curve diagram shown.

[0045] from Figure 3 and Figure 4 It can be seen that under the same test conditions, after trivalent and tetravalent manganese ions are integrated into the cerium dioxide lattice to form a cerium-manganese solid solution oxide material, its CV area is significantly larger than the CV area of ​​commercial ceria. By calculation, it can be concluded that the capacitance value of commercial ceria at a scanning speed of 1mV / s is 27.32F / g, Ce 0.8 Mn 0.2 The capacitance value of the cerium manganese solid solution oxide material is 42.95F / g at a scanning rate of 1mV / s. 0.8 Mn0.2 The CV value of the cerium-manganese solid solution oxide material increased by 157.02% compared with that of commercial cerium dioxide.

[0046] Example 3

[0047] The cerium-manganese solid solution oxide material Ce was prepared according to the method of Example 1. 0.6 Mn 0.4 、Ce 0.7 Mn 0.3 、Ce 0.8 Mn 0.2 and Ce 0.9 Mn 0.1 During the preparation process, the molar ratio of the raw materials cerium acetate and manganese acetate in step (1) is the same as the molar ratio of cerium to manganese in the cerium-manganese solid solution oxide material required for preparation, and the other preparation processes are the same as those in Example 1.

[0048] The photocurrent test in the electrochemical test was carried out on each prepared cerium manganese solid solution oxide material and commercial cerium dioxide. The specific process is as follows:

[0049] According to the working electrode preparation method in Example 2, the prepared Ce 0.6 Mn 0.4 、Ce 0.7 Mn 0.3 、Ce 0.8 Mn 0.2 、Ce 0.9 Mn 0.1 and a commercial ceria working electrode, and then using a CHI760E electrochemical workstation, Ce 0.6 Mn 0.4 、Ce 0.7 Mn 0.3 、Ce 0.8 Mn 0.2 、Ce 0.9 Mn 0.1 The commercial cerium dioxide was tested. The light source used was full light. The light blocking time of each sample was 20s. The test results were Figure 5 The photocurrent spectrum shown in the figure shows that Ce 0.6 Mn 0.4 、Ce 0.7 Mn 0.3 、Ce 0.8 Mn 0.2 、Ce 0.9 Mn 0.1 The photocurrent intensities of the samples are greater than those of commercial cerium dioxide.

[0050] The present invention includes but is not limited to the above embodiments. Any equivalent replacement or partial improvement made under the principle of the spirit of the present invention shall be deemed to be within the protection scope of the present invention.

Claims

1. A cerium-manganese solid solution oxide material, characterized in that: The chemical composition of the cerium manganese solid solution oxide material is expressed as Ce in terms of atomic ratio. X Mn Y O2, wherein X=0.6-0.9, Y=0.4-0.1, X+Y=1.

2. The cerium-manganese solid solution oxide material according to claim 1, characterized in that: The cerium-manganese solid solution oxide material has a cubic crystal structure, and cerium and manganese ions occupy the same lattice position, presenting a solid solution state.

3. The cerium-manganese solid solution oxide material according to claim 1, characterized in that: The cerium-manganese solid solution oxide material has a grain size of 5-50 nm and exhibits a single cubic fluorite phase.

4. The method for preparing the cerium-manganese solid solution oxide material according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) weighing a certain proportion of cerium acetate and manganese acetate powder at room temperature and adding them into deionized water, dissolving them under stirring to obtain a uniform, clear and transparent mixed solution; (2) preparing a sodium hydroxide solution, pouring the mixed solution obtained in step (1) and the sodium hydroxide solution into a sealed inner container in proportion, keeping the poured solution occupying 70-90% of the volume of the inner container, heating to 110-150° C. for reaction, and keeping the temperature for 20-30 hours; (3) filtering the mixture obtained after the reaction in step (2), taking the precipitate, washing the precipitate repeatedly with deionized water and anhydrous ethanol for 5 to 6 times, and then drying the precipitate; the drying temperature is 60 to 90° C., and the insulation time is 12 to 30 hours; (4) placing the product after drying in step (3) in a muffle furnace for calcination at a temperature of 500 to 600° C. for a holding time of 3 to 5 hours; the gray-black powder obtained after calcination is the cerium-manganese solid solution oxide material.

5. The method for preparing the cerium-manganese solid solution oxide material according to claim 4, characterized in that: In step (1), the molar ratio of cerium acetate to manganese acetate is (1.5-10):1; and the total concentration of metal ions in the mixed solution is 0.5-2 mol / L.

6. The method for preparing the cerium-manganese solid solution oxide material according to claim 4, characterized in that: In step (2), the concentration of the sodium hydroxide solution is 5 to 7 mol / L.

7. The method for preparing the cerium-manganese solid solution oxide material according to claim 4, characterized in that: In step (2), the volume ratio of the sodium hydroxide solution to the mixed solution is (3-5):

1.

8. The use of the cerium-manganese solid solution oxide material according to any one of claims 1 to 3 in photocompatibilization, characterized in that: The cerium manganese solid solution oxide material has a capacitance value increased by more than 50% compared with commercial cerium dioxide, and can capture light energy under illumination conditions to obtain a higher capacitance value; the cerium manganese solid solution oxide material is used in the preparation of supercapacitors.

9. The use of the cerium-manganese solid solution oxide material in photocompatibilization according to claim 8, characterized in that: The lighting conditions include sunlight, ultraviolet light, visible light and infrared light.

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