Method for preparing mixed-phase-structure iron oxyhydroxide through solvent regulation and control and application of mixed-phase-structure iron oxyhydroxide
By ultrasonic dispersing iron trichloride in dimethyl sulfoxide and water solvent, a mixed-phase structure of iron hydroxyl oxide was prepared and loaded on a semiconductor substrate, which solved the problem of limited catalytic activity of iron hydroxyl oxide and by-products, and significantly improved the photoelectricity Catalytic properties.
Patent Information
- Application Number
- CN202411277433.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2024-12-10
AI Technical Summary
In the prior art, the single-phase catalytic activity of iron hydroxyoxide is limited by its intrinsic characteristics, and it is difficult to accurately control when preparing mixed-phase iron hydroxyoxide, and it is easy to introduce iron oxide by-products, resulting in limited improvement in catalytic performance.
By ultrasonic dispersing iron trichloride in a mixed solvent of dimethyl sulfoxide and water, controlling the solvent ratio and reaction conditions, a mixed phase structure iron hydroxyl oxide was prepared and supported on a semiconductor substrate for use in the field of photoelectro-catalytics .
The surface carrier separation efficiency and water oxidation activity of bismuth vanadate film are significantly improved, providing a controllable mixed phase regulation scheme, and improving the oxygen evolution catalytic performance.
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Figure CN119100455A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of photocatalysis and photoelectrocatalysis material preparation, and specifically relates to a method for preparing mixed-phase structured iron oxyhydroxide by solvent regulation and application. Background Art
[0002] Iron oxyhydroxide (FeOOH) is a promising oxygen evolution active material due to its high activity, low cost, natural abundance and environmental friendliness in alkaline media and has therefore received extensive research. The iron oxyhydroxide studied in the mainstream is mainly divided into two categories, namely amorphous phase and crystalline phase. Among them, amorphous iron oxyhydroxide is prone to structural changes under high anode voltage conditions and oxidizes and dissolves rapidly in the electrolyte, so the structure is very unstable. Well-crystallized iron oxyhydroxide is more stable without affecting the catalytic performance, so this type of crystalline iron oxyhydroxide has received extensive attention and research. However, for crystalline iron oxyhydroxide, its oxygen evolution activity is closely related to the crystal form. At present, there are four main crystal forms of iron oxyhydroxide, namely α, β, γ and δ, but the oxygen evolution catalytic activity of single-phase iron oxyhydroxide is limited by its intrinsic characteristics and is difficult to improve. The mixed crystal phase may greatly improve the defects of the single-phase catalytic performance of iron oxyhydroxide due to its synergistic effect, so it is worth further study. On the other hand, the current method for preparing mixed-phase oxyhydroxide inevitably introduces iron oxide by-products, and it is difficult to accurately control the preparation of mixed-phase oxyhydroxide. Summary of the invention
[0003] In order to solve the technical problems raised in the above background technology, the present invention proposes a method and application of preparing mixed-phase structured iron oxyhydroxide by solvent regulation.
[0004] The specific technical solutions of the present invention are as follows: The first aspect of the present invention provides a method for preparing a mixed-phase structured iron oxyhydroxide by solvent regulation, comprising the following steps: Step 1: ultrasonically dispersing ferric chloride in a mixed solvent of dimethyl sulfoxide and water to obtain a precursor solution; Step 2: placing the precursor solution in a container, reacting for a period of time, and then drying and collecting powder particles to obtain a mixed phase structure iron oxyhydroxide.
[0005] As a further illustration of the present invention, in step 1, the ferric chloride is ultrasonically dispersed in a mixed solvent of dimethyl sulfoxide and water at an ultrasonic power of 200-300 W and a frequency of 40-50 kHz.
[0006] As a further illustration of the present invention, the volume ratio of water to dimethyl sulfoxide is between 5:1 and 1:3.
[0007] As a further illustration of the present invention, the molar concentration of ferric chloride in the precursor solution is 10-15 mM.
[0008] As a further illustration of the present invention, in step 2, the precursor solution is placed in a container and reacted for a period of time, and then dried to collect powder particles, specifically: The precursor solution is placed in a petri dish or beaker, placed in an oven to react for a period of time, and then dried to collect powder particles.
[0009] As a further illustration of the present invention, in step 2, the reaction temperature of the precursor solution is 50-60° C., and the reaction time is 10-15 h.
[0010] A second aspect of the present invention provides an oxygen evolution active material, which is prepared by the above method.
[0011] The third aspect of the present invention provides the application of the mixed-phase structured oxyhydroxide iron in the field of photoelectrocatalysis, and the precursor solution obtained in the above step 1 is combined with a semiconductor substrate to obtain a semiconductor film loaded with the mixed-phase structured oxyhydroxide iron.
[0012] As a further illustration of the present invention, the semiconductor substrate is a bismuth vanadate or iron oxide film.
[0013] As a further illustration of the present invention, the process of combining the precursor solution with the semiconductor substrate specifically includes: The semiconductor substrate is placed in the precursor solution obtained in the above step 1, and reacted at a temperature of 50-60° C. for 10-15 hours to grow mixed-phase structured iron oxyhydroxide on the surface of the semiconductor substrate.
[0014] Compared with the prior art, the present invention has the following beneficial technical effects: 1. The present invention utilizes a chemical bath method to prepare ferric oxyhydroxide, and the preparation process is simple and the conditions are mild.
[0015] 2. The present invention controls the hydrolysis kinetics by changing the solvent ratio in the precursor, thereby changing the microenvironment crystallization dynamics and preparing a mixed-phase ferric hydroxide oxide.
[0016] 3. The mixed-phase oxyhydroxy iron prepared by the present invention is loaded onto the bismuth vanadate photoanode film, which significantly promotes the carrier separation efficiency on the surface of the bismuth vanadate film and improves the surface water oxidation activity.
[0017] The preparation strategy of the present invention is simple and controllable, and provides an effective alternative for the controllable mixed-phase regulation of mixed-phase iron oxyhydroxide.
[0018] Other features and advantages of the technical solution will be described in the subsequent description, and partly become apparent from the description, or understood by implementing the technical solution. The purpose and other advantages of the technical solution can be achieved and obtained through the structures specifically pointed out in the written description and the drawings.
[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings are used to provide further understanding of the present technical solution and constitute a part of the specification. Together with the embodiments of the present technical solution, they are used to explain the present technical solution and do not constitute a limitation to the present technical solution.
[0021] Figure 1 Schematic diagram of the mechanism of preparing mixed-phase iron oxyhydroxide by solvent regulation of the present invention.
[0022] Figure 2 This is the precursor solution used in specific embodiment 1, specific embodiment 2, specific embodiment 3, comparative example 1 and comparative example 2 of the present invention, in which 1:0, 5:1, 3:1, 1:3 and 1:5 are the volume ratios of water and dimethyl sulfoxide in the solution, respectively.
[0023] Figure 3 It is the pH value of the precursor solution used in Specific Example 1, Specific Example 2, Specific Example 3, Comparative Example 1 and Comparative Example 2 of the present invention.
[0024] Figure 4 This is a transmission electron microscopic image analysis of comparative examples 1 and 2 of the present invention; wherein A is the transmission electron microscopic image and high-resolution morphology of comparative example 1, and B is the transmission electron microscopic image and high-resolution morphology of comparative example 2.
[0025] Figure 5 This is a transmission electron microscopy image analysis of specific embodiment 1 of the present invention; wherein A is the transmission electron microscopy image and high-resolution morphology of specific embodiment 1, B is a high-resolution image selected and enlarged in Figure A, and C is a high-resolution image selected and enlarged in Figure A.
[0026] Figure 6 This is a transmission electron microscopy image analysis of specific embodiment 2 of the present invention; wherein A is the transmission electron microscopy image of specific embodiment 2, B is the high-resolution morphology of the transmission electron microscopy image of specific embodiment 2, C is the Fourier transform image corresponding to α in specific embodiment 2, and D is the Fourier transform image corresponding to β in specific embodiment 2.
[0027] Figure 7This is a transmission electron microscopy image analysis of specific embodiment 3 of the present invention; wherein A is the transmission electron microscopy image and high-resolution morphology of specific embodiment 3, B is the high-resolution image selected and enlarged in Figure A, and C is the high-resolution image selected and enlarged in Figure A.
[0028] Figure 8 It is the infrared spectrum of the bismuth vanadate / iron oxyhydroxide composite film in specific embodiment 4 of the present invention and comparative examples 3, 4 and 5.
[0029] Fig. 9 The electrochemical active area and oxygen evolution activity diagram of the bismuth vanadate / iron oxyhydroxide composite film in specific embodiment 4 of the present invention and comparative examples 3, 4, and 5; wherein A is the electrochemical active area and B is the oxygen evolution activity diagram. DETAILED DESCRIPTION
[0030] The preferred embodiments of the present technical solution are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present technical solution, and are not used to limit the present technical solution.
[0031] For crystalline phase hydroxyl iron, its oxygen evolution activity is closely related to the crystal form. Currently, there are four main crystal forms of hydroxyl iron, namely α, β, γ and δ, but the oxygen evolution catalytic activity of single-phase hydroxyl iron is limited by its intrinsic characteristics and is difficult to improve. The mixed crystal phase may greatly improve the defects of the single-phase catalytic performance of hydroxyl iron due to its synergistic effect, so it is worth further study. On the other hand, the current method for preparing mixed-phase hydroxyl iron will inevitably introduce iron oxide by-products, and it is difficult to accurately control the preparation of mixed-phase hydroxyl iron.
[0032] Based on the solution of the above technical problems, the present invention provides a method for preparing a mixed-phase structured iron oxyhydroxide by solvent regulation, comprising the following steps: Step 1: Ultrasonic dispersion of ferric chloride in a mixed solvent of dimethyl sulfoxide and water to obtain a precursor solution.
[0033] In the above step 1, ferric chloride is ultrasonically dispersed in a mixed solvent of dimethyl sulfoxide and water at an ultrasonic power of 200-300 W and a frequency of 40-50 kHz; the ultrasonic power may be, for example, 200 W, 230 W, 250 W, 270 W, 300 W, etc., and the frequency may be, for example, 40 kHz, 43 kHz, 45 kHz, 47 kHz, 50 kHz, etc.
[0034] The volume ratio of water to dimethyl sulfoxide is between 5:1 and 1:3, for example, 5:1, 3:1, 1:3, etc. The molar concentration of ferric chloride in the precursor solution is 10-15 mM, for example, 10 mM, 12 mM, 13 mM, 15 mM, etc.
[0035] Step 2: Place the precursor solution in a container and react for a period of time, then dry and collect the powder particles to obtain a mixed phase structure iron oxyhydroxide.
[0036] In the above step 2, the precursor solution is placed in a container to react for a period of time and then dried to collect powder particles. Specifically, the precursor solution is placed in a culture dish or beaker, placed in an oven to react for a period of time and then dried to collect powder particles.
[0037] In step 2, the reaction temperature of the precursor solution is 50-60°C, and the reaction time is 10-15h, wherein the reaction temperature can be, for example, 50°C, 52°C, 55°C, 57°C, 60°C, etc.; the reaction time can be, for example, 10h, 12h, 13h, 14h, 15h, etc.
[0038] Through the above preparation method, a mixed phase structure iron oxyhydroxide oxygen evolution active material can be obtained.
[0039] The present invention also provides an application of the mixed-phase structured oxyhydroxide iron in the field of photoelectrocatalysis, wherein the precursor solution obtained in the above step 1 is combined with a semiconductor substrate to obtain a semiconductor loaded with the mixed-phase structured oxyhydroxide iron.
[0040] In some achievable embodiments, the semiconductor substrate is a bismuth vanadate film or an iron oxide film. The bismuth vanadate film can be prepared by an electrodeposition method.
[0041] The process of combining the precursor solution with the semiconductor substrate specifically includes: placing the semiconductor substrate in the precursor solution obtained in the above step 1, reacting at a temperature of 50-60° C. for 10-15 hours, so that the mixed phase structure of iron oxyhydroxide grows on the surface of the semiconductor substrate.
[0042] In order to verify the effectiveness of the present invention in regulating the mixed phase structure of ferric hydroxide to promote oxygen evolution activity, the above-mentioned method can be used to prepare a mixed phase ferric hydroxide-loaded bismuth vanadate photoanode film, and the effectiveness of the present invention can be verified by testing the catalytic activity of the composite film.
[0043] The mixed-phase iron oxyhydroxide-loaded bismuth vanadate photoanode film prepared by the above method is taken out from the culture dish, rinsed with ultrapure water, and then blown dry with nitrogen before conducting relevant tests on the oxygen evolution reaction.
[0044] The present invention is described in detail below in conjunction with specific embodiments and drawings. Example 1
[0045] A method for preparing a mixed-phase iron oxyhydroxide structure by solvent regulation comprises the following steps: Step 1: dispersing ferric chloride in a mixed solvent of dimethyl sulfoxide and water by ultrasonic method at an ultrasonic power of 250 W and a frequency of 45 kHz to obtain a precursor solution; The volume of the mixed solvent is 10 mL; the volume ratio of water to dimethyl sulfoxide is 5:1; the molar concentration of ferric chloride in the precursor solution is 10 mM. See the solution picture. Figure 2 Shown in the middle left 2.
[0046] Step 2: Place the above precursor solution in a culture dish or beaker, place it in an oven to react for a period of time, then dry and collect the powder particles to obtain a mixed phase structure iron hydroxide oxide; wherein the oven temperature is maintained at 55°C and the reaction time is 12h. Example 2
[0047] The preparation steps are the same as those in Example 1, except that the volume ratio of water to dimethyl sulfoxide in step 1 is 3:1, and the solution photo is Figure 2 Shown as 3rd from the middle left. Example 3
[0048] The preparation steps are the same as those in Example 1, except that the volume ratio of water to dimethyl sulfoxide in step 1 is 1:3, and the solution photo is Figure 2 Shown as 2nd in the middle right. Example 4
[0049] A method for preparing a bismuth vanadate film loaded with mixed-phase structure iron oxyhydroxide comprises the following steps: Step 1: dispersing ferric chloride in a mixed solvent of dimethyl sulfoxide and water by ultrasonic method at an ultrasonic power of 250 W and a frequency of 45 kHz to obtain a precursor solution; The volume of the mixed solvent is 10 mL; the volume ratio of water to dimethyl sulfoxide is 3:1; and the molar concentration of ferric chloride in the precursor solution is 10 mM.
[0050] Step 2: Place the prepared bismuth vanadate film in a culture dish or beaker containing the above-mentioned precursor solution, and place it in an oven to react for a period of time. The mixed phase structure of iron oxyhydroxide will grow on the bismuth vanadate film; wherein, the oven temperature is maintained at 55°C and the reaction time is 12 hours.
[0051] The composite film prepared by this method is denoted as BVO / FeOOH(α+β).
[0052] Comparative Example 1: The preparation steps are the same as those in Example 1, except that the volume ratio of water to dimethyl sulfoxide in step 1 is 1:0, and the solution photo is Figure 2 Shown as 1 on the left.
[0053] Comparative Example 2: The preparation steps are the same as those in Example 1, except that the volume ratio of water to dimethyl sulfoxide in step 1 is 1:5, and the solution photo is Figure 2 Shown as 1 on the right.
[0054] Comparative Example 3: The preparation steps are the same as those in Example 4, except that the volume ratio of water to dimethyl sulfoxide in step 1 is 1:0. The prepared composite film is denoted as BVO / FeOOH(β).
[0055] Comparative Example 4: The preparation steps are the same as those in Example 4, except that the volume ratio of water to dimethyl sulfoxide in step 1 is 1:5. The prepared composite film is denoted as BVO / FeOOH(α).
[0056] Comparative Example 5: Bismuth vanadate thin films were prepared by electrodeposition. The film surface was not loaded with iron oxyhydroxide as a control group, denoted as BVO.
[0057] In order to illustrate the principle of preparing mixed-phase oxyhydroxide of the present invention, the present invention performs a pH test on the solvent of oxyhydroxide of the oxyhydroxide prepared in specific examples 1, 2, 3 and comparative examples 1 and 2. Figure 3 As shown. It can be seen that as the content of dimethyl sulfoxide in the solvent increases, the pH value of the solution gradually increases. This is because the introduction of dimethyl sulfoxide can change the microenvironment of the aqueous solution. One dimethyl sulfoxide molecule can react with one water molecule to form [(DMSO)H] + And release an OH-, so that the pH of the solution changes. In the micro-region of dimethyl sulfoxide and water molecules, the crystallization dynamics of iron oxyhydroxide changes with the change of local pH value, so an α phase is produced, and the water molecules that have not reacted with dimethyl sulfoxide react normally to form a β phase. When the content of dimethyl sulfoxide in the solvent reaches a certain value (such as specific embodiment 1), a mixed phase α+β can be formed. The formation process diagram is shown in Figure 1 shown.
[0058] In order to illustrate the effect of preparing mixed-phase oxyhydroxide of the present invention, the present invention performs transmission electron microscopy analysis on the oxyhydroxide of the specific examples 1, 2, 3 and comparative examples 1 and 2, and calibrates the physical phases thereof. The results are as follows: Figure 4-7 As shown. Figure 4 It can be seen from A that the iron oxyhydroxide of specific comparative example 1 presents a β single phase; Figure 4 B shows that the iron oxyhydroxide of Comparative Example 2 presents an α phase. Figure 5-7 It can be seen that the iron oxyhydroxide prepared in specific examples 1, 2 and 3 presents a mixed phase α+β and no other impurities. By adjusting the volume ratio of dimethyl sulfoxide and water in the solvent, a mixed phase α+β iron oxyhydroxide without impurities can be obtained.
[0059] In order to further illustrate the effective application of the mixed-phase iron oxyhydroxide prepared by the present invention in the field of photoelectrocatalysis, the structure and catalytic performance of the composite film of the specific embodiment 4 and comparative examples 3, 4, and 5 of the present invention were characterized. Figure 8 and Fig. 9 shown.
[0060] from Figure 8 It can be seen that based on the characteristic infrared peaks of BVO in Comparative Example 5 (863 and 735 cm -1 ), BVO / FeOOH(α) appeared at 792 cm -1 The characteristic peak of α-phase iron oxyhydroxide at 697 cm-1 indicates that the bismuth vanadate film of comparative example 4 successfully loaded α-phase iron oxyhydroxide on its surface; BVO / FeOOH(β) appeared at 697 cm-1 -1 The characteristic peak of β-phase iron oxyhydroxide at 697 cm-1 indicates that the bismuth vanadate film of comparative example 3 successfully loaded β-phase iron oxyhydroxide on its surface; BVO / FeOOH (α+β) also appeared at 697 cm-1 -1 and 792 cm -1 The characteristic peaks of , indicate that the surface of the bismuth vanadate film of Example 4 is successfully loaded with a mixed phase of α+β iron oxide.
[0061] Fig. 9 A is the electrochemically active surface area estimated by CV of the composite film of specific Example 4 and Comparative Examples 3, 4, and 5. It can be seen that the BVO / FeOOH (α+β) film in Example 4 has the largest double-layer capacitance value, indicating that the film has the largest electrochemically active area, and the mixed phase of iron oxyhydroxide can help the bismuth vanadate film provide more active sites for oxygen evolution reaction. Fig. 9 B is the oxygen evolution reaction activity of the composite film of specific example 4 and comparative examples 3, 4, and 5. It can be seen that the BVO / FeOOH (α+β) film in example 4 has the smallest overpotential, indicating that the loading of the mixed phase of iron oxyhydroxide on the surface of the bismuth vanadate film can improve the oxygen evolution reaction activity of the film.
[0062] The active sites of the optimized bismuth vanadate / iron oxyhydroxide photoanode film are 1.95 times higher than that of pure bismuth vanadate, and 1.39 and 1.20 times higher than those of the film modified with single-phase iron oxyhydroxide, respectively; the oxygen evolution activity of the optimized bismuth vanadate / iron oxyhydroxide photoanode film is 2.50 times higher than that of pure bismuth vanadate film, and 1.97 and 1.91 times higher than those of the film modified with single-phase iron oxyhydroxide, respectively, and the oxygen evolution reaction activity is effectively promoted.
[0063] Obviously, those skilled in the art can make various changes and modifications to the technical solution without departing from the spirit and scope of the technical solution. Thus, if these modifications and variations of the technical solution fall within the scope of the claims of the technical solution and their equivalents, the technical solution is also intended to include these modifications and variations.
Claims
1. A method for preparing a mixed phase structure iron oxyhydroxide by solvent regulation, It is characterized in that The steps include: Step 1: ultrasonically dispersing ferric chloride in a mixed solvent of dimethyl sulfoxide and water to obtain a precursor solution; Step 2: placing the precursor solution in a container, reacting for a period of time, and then drying and collecting powder particles to obtain a mixed phase structure iron oxyhydroxide.
2. The method for preparing mixed-phase iron oxyhydroxide by solvent regulation as claimed in claim 1, It is characterized in that In step 1, the ferric chloride is ultrasonically dispersed in a mixed solvent of dimethyl sulfoxide and water at an ultrasonic power of 200-300 W and a frequency of 40-50 kHz.
3. The method for preparing mixed-phase iron oxyhydroxide by solvent regulation as claimed in claim 1, It is characterized in that The volume ratio of water to dimethyl sulfoxide is between 5:1 and 1:
3.
4. The method for preparing mixed-phase iron oxyhydroxide by solvent regulation as claimed in claim 1, It is characterized in that The molar concentration of ferric chloride in the precursor solution is 10-15 mM.
5. The method for preparing mixed-phase iron oxyhydroxide by solvent regulation as claimed in claim 1, It is characterized in that In step 2, the precursor solution is placed in a container and reacted for a period of time, and then dried to collect powder particles, specifically: The precursor solution is placed in a petri dish or beaker, placed in an oven to react for a period of time, and then dried to collect powder particles.
6. The method for preparing mixed-phase iron oxyhydroxide by solvent regulation as claimed in claim 1, It is characterized in that In step 2, the reaction temperature of the precursor solution is 50-60° C., and the reaction time is 10-15 h.
7. An oxygen evolution active material, It is characterized in that The oxygen evolution active material is prepared by the method according to any one of claims 1-6.
8. Application of mixed phase iron oxyhydroxide in the field of photoelectrocatalysis, It is characterized in that The precursor solution obtained in step 1 according to any one of claims 1 to 6 is combined with a semiconductor substrate to obtain a semiconductor film loaded with iron oxyhydroxide having a mixed phase structure.
9. Application of the mixed-phase iron oxyhydroxide as claimed in claim 8 in the field of photoelectrocatalysis, It is characterized in that The semiconductor substrate is a bismuth vanadate or iron oxide film.
10. Application of the mixed-phase iron oxyhydroxide according to claim 8 in the field of photoelectrocatalysis, It is characterized in that The process of combining the precursor solution with the semiconductor substrate specifically includes: Placing the semiconductor substrate in the precursor solution obtained in step 1 of any one of claims 1 to 6, reacting at a temperature of 50-60° C. for 10-15 hours, so that the mixed phase structure of iron oxyhydroxide grows on the surface of the semiconductor substrate.