A chlorinated hematin intercalated manganese-iron oxide electrode and its preparation method and application

Abstract

The application belongs to the technical field of electrocatalytic material synthesis, and discloses a chlorinated hematin embedded manganese-iron oxide electrode and a preparation method and application thereof. A sodium sulfate solution is used as a supporting electrolyte, manganese sulfate, ferrous sulfate and chlorinated hematin are added to prepare an electroplating solution, a graphite matrix is immersed in the electroplating solution as a working electrode, a titanium sheet is used as a counter electrode, and a saturated calomel electrode is used as a reference electrode to construct a three-electrode system. A continuous cyclic voltammetry method is used, and manganese-iron oxide is deposited on the surface of the matrix through multiple cathode deposition and anode oxidation. In the continuous circulation process, chlorinated hematin is also adsorbed and embedded in the manganese-iron oxide to obtain a chlorinated hematin embedded manganese-iron oxide electrode. The method can realize the compounding of metal oxides and complexes, and the activation of the material in the circulation process. The obtained electrode has good biocompatibility and stability, and can be used to catalyze the oxidation of ascorbic acid under neutral conditions to promote hydrogen production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalytic material synthesis, and particularly relates to a chlorinated hematin embedded manganese iron oxide electrode and a preparation method and application thereof. BACKGROUND

[0002] At present, the main preparation methods of manganese and iron oxides or hydroxides as electrode materials include electrochemical deposition, hydrothermal method, solvothermal method, vacuum sputtering method, sol-gel method, etc. The hydrothermal method, solvothermal method and sol-gel method usually need to prepare a precursor first, and then obtain the manganese iron oxide by high-temperature calcination, so the preparation method is relatively complex to operate. The vacuum sputtering method needs to use special instruments and equipment, and the cost is high. The electrochemical deposition method is simple to operate, low in cost, and can obtain metal oxides with uniform distribution and strong adhesion. In the existing research, the electrochemical deposition method is often used to prepare manganese iron oxide electrodes, but there is almost no research on introducing chlorinated hematin in the deposition process.

[0003] In the existing research, manganese iron and other transition metal oxides are often used as supercapacitor electrode materials or used to replace traditional noble metal materials as catalysts. As a catalyst, electrolysis of water to produce hydrogen is also a common use of the electrode material at present, but few researchers use transition metal oxide catalysts to promote hydrogen production by catalyzing the oxidation of ascorbic acid. SUMMARY

[0004] In order to solve the above-mentioned shortcomings and deficiencies in the prior art, the primary purpose of the present application is to provide a preparation method of a chlorinated hematin embedded manganese iron oxide electrode. The method uses a continuous cyclic voltammetry method to prepare a metal oxide electrode, and innovatively introduces chlorinated hematin. In the continuous oxidation-reduction process, the chlorinated hematin is embedded in the deposited manganese iron oxide, and the three are tightly combined to form a chlorinated hematin manganese iron oxide composite electrode. By embedding the chlorinated hematin, the performance of the manganese iron oxide electrode is optimized, and the application of efficiently catalyzing the oxidation of ascorbic acid to promote hydrogen production is realized at the same time.

[0005] Another purpose of the present application is to provide a chlorinated hematin embedded manganese iron oxide electrode prepared by the above preparation method.

[0006] Still another purpose of the present application is to provide an application of the above-mentioned chlorinated hematin embedded manganese iron oxide electrode.

[0007] The purposes of the present application are achieved by the following technical solutions.

[0008] A preparation method of a chlorinated hematin embedded manganese iron oxide electrode, comprising the following steps:

[0009] (1) the concentration of sodium sulfate solution as supporting electrolyte is 0.1 mol / L, and manganese sulfate, ferrous sulfate and hemin are added to prepare the electroplating solution, wherein the concentration of manganese sulfate and ferrous sulfate in the electroplating solution is 0.001-0.01 mol / L, and the concentration of hemin in the electroplating solution is 0.03-0.1 mmol / L;

[0010] (2) the graphite matrix is immersed in the electroplating solution as a working electrode, a titanium sheet is used as a counter electrode, and a saturated calomel electrode (SCE) is used as a reference electrode to construct a three-electrode system, the temperature range for electrodeposition is controlled to be 15-30℃, and continuous cyclic voltammetry is used to deposit manganese-iron oxides on the surface of the graphite matrix through multiple cathodic deposition and anodic oxidation, and in the continuous circulation process, hemin is also adsorbed and embedded in the manganese-iron oxides to form a composite electrode of metal oxides and complexes;

[0011] (3) the composite electrode of metal oxides and complexes prepared in step (2) is subjected to constant temperature drying treatment to obtain a hemin-embedded manganese-iron oxide electrode.

[0012] In step (1), the molar ratio of manganese to iron in the electroplating solution is 1:1.

[0013] In step (2), the surface size of the graphite matrix involved in deposition is 0.5-5 cm 2 , and the remaining immersed solution part is coated with insulating glue to control the reaction area.

[0014] In step (2), the deposition potential range of the cyclic voltammetry is-0.8-1.4 V (vs. SCE), the deposition cycle number is 5-40, and the scan rate is 0.05 V s -1 .

[0015] In step (3), the temperature of the constant temperature drying is 30-50℃.

[0016] A hemin-embedded manganese-iron oxide electrode prepared by the above preparation method.

[0017] The above hemin-embedded manganese-iron oxide electrode as a working electrode is applied to electrocatalytic oxidation of ascorbic acid.

[0018] The application comprises the following steps: a mixed solution of sodium sulfate and ascorbic acid is used as an anode chamber solution, and a sodium sulfate solution is used as a cathode chamber solution; the hemin-embedded manganese-iron oxide electrode is used as a working electrode, a titanium wire is used as a counter electrode, and a saturated calomel electrode (SCE) is used as a reference electrode to construct a three-electrode system, and a chronoamperometry method is used to apply a bias to the system to realize the oxidation of ascorbic acid and promote the production of hydrogen.

[0019] The concentration of sodium sulfate in the anode chamber solution is 0.1 mol / L, and the concentration of ascorbic acid is 0.001-0.1 mol / L; the concentration of sodium sulfate solution in the cathode chamber is 0.1 mol / L.

[0020] A 2 mL glass tube with scales is arranged in the cathode chamber, and the scale of the glass tube is read by using the air exhaust method, so as to obtain the hydrogen production volume;

[0021] The applied bias voltage range of the chronoamperometry method is 0.4-1.0 V (vs. SCE).

[0022] The present application has the following advantages and effects relative to the prior art:

[0023] (1) The electrode is prepared by using the continuous cyclic voltammetry co-deposition method, and the operation is simple, the preparation process introduces hemin chloride, the composite of the metal oxide and the complex can be realized, and the material activation is achieved in the cyclic process.

[0024] (2) The electrode prepared by the present application introduces hemin chloride, and the obtained electrode has good biocompatibility and high stability.

[0025] (3) The hemin chloride embedded manganese iron oxide electrode prepared by the present application has good electrocatalytic oxidation effect on ascorbic acid, and the catalytic performance of the electrode on ascorbic acid is better than that of a graphite electrode.

[0026] (4) The hemin chloride embedded manganese iron oxide electrode prepared by the present application realizes the catalytic oxidation of ascorbic acid to produce hydrogen under the neutral condition of 0.5 V (vs. SCE). BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is the current density-potential curve of the hemin chloride embedded manganese iron oxide electrode prepared by the continuous cyclic voltammetry co-deposition method in Example 1 of the present application.

[0028] Figure 2 It is the cyclic voltammetry curve of the hemin chloride embedded manganese iron oxide electrode electrolyzing ascorbic acid with different concentrations in Example 2 of the present application.

[0029] Figure 3 It is the curve of the hydrogen evolution amount on the counter electrode with time in the three-electrode system constructed by using the hemin chloride embedded manganese iron oxide electrode as the working electrode, the titanium wire as the counter electrode, and the saturated calomel electrode (SCE) as the reference electrode in Example 3 of the present application. DETAILED DESCRIPTION

[0030] The present application will be further described in detail below in combination with examples, but the implementation manner of the present application is not limited thereto.

[0031] According to the design purpose of the present application, simple substitution of similar substances and changes in size and shape, such as changing the size of the co-deposition preparation device of the present application (such as changing the size of the working electrode, the counter electrode, and the reference electrode), simply changing the concentration, ratio, or deposition potential, preparation temperature, etc. of manganese-iron chlorinated hematin all fall within the scope of the present application; the experimental methods used in the following examples are common methods in the chemical field (except as specifically stated); the chemical reagents and materials used are commercially available (except as specifically stated).

[0032] Example 1 Preparation of chlorinated hematin embedded manganese-iron oxide electrode

[0033] The chlorinated hematin embedded manganese-iron oxide electrode of this example is prepared by the following method:

[0034] (1) Prepare a graphite electrode, control the reaction area to be 1 x 1 cm 2 The remaining immersion solution part is covered with insulating glue, and the surface of the graphite electrode is polished with sandpaper to remove surface impurities; then the graphite electrode is soaked in deionized water and placed in an ultrasonic cleaning machine for 30 minutes, and after washing, it is placed in an electric heating constant temperature air drying oven for drying;

[0035] (2) Prepare 250 mL of 0.1 mol / L sodium sulfate solution, and prepare a mixed solution of manganese sulfate solution, ferrous sulfate solution, and chlorinated hematin solution with the solution as the supporting electrolyte, with concentrations of 0.01 mol / L, 0.01 mol / L, and 0.03 mmol / L, respectively;

[0036] (3) Control the temperature range of electrodeposition to be 15-30°C, use cyclic voltammetry electrodeposition technology, in a three-electrode system, the working electrode is the graphite electrode treated in step (1), the counter electrode is a titanium sheet, the reference electrode is a saturated calomel electrode (SCE), the plating solution is the mixed solution obtained in step (2), the deposition potential range is -0.8V-1.4V, the number of cycles is 10, and the scan rate is 0.05V s -1 Manganese-iron oxide is deposited on the graphite electrode through continuous oxidation and reduction, and chlorinated hematin is embedded in the manganese-iron oxide during the cycle, forming a composite electrode of metal oxide and complex, and the current density-potential curve during preparation is shown in Figure 1 ;

[0037] (4) Place the metal oxide and complex composite electrode obtained by electrodeposition in step (3) in a constant temperature drying oven to dry to obtain a chlorinated hematin embedded manganese-iron oxide electrode.

[0038] Example 2 Electro-catalytic oxidation of different concentrations of ascorbic acid

[0039] The cyclic voltammetry technology was used, the chlorin hemoglobin embedded manganese iron oxide electrode prepared in Example 1 was used as the working electrode, the titanium sheet was used as the counter electrode, the saturated calomel electrode (SCE) was used as the reference electrode, the 0.1 mol / L sodium sulfate solution was used as the supporting electrolyte, and different concentrations of ascorbic acid solution was used as the electrolyte, and a three-electrode electrochemical reaction system was constructed.

[0040] As shown in Figure 2 , curve 1 corresponds to the blank solution of 0.1 mol / L sodium sulfate solution, and curves 2-6 correspond to the concentrations of ascorbic acid of 0.001 mol / L, 0.002 mol / L, 0.005 mol / L, 0.01 mol / L, and 0.025 mol / L, respectively. Figure 2 It can be seen that when the chlorin hemoglobin embedded manganese iron oxide electrode is used as the working electrode, the oxidation peak of ascorbic acid starts at about 0V, which is about 0.1V lower than the oxidation peak of ascorbic acid on the bare graphite electrode; at the same time, with the increase of the concentration of ascorbic acid, the peak current of the oxidation peak also gradually increases, and the peak current of the oxidation peak of ascorbic acid on the bare graphite electrode is larger. It can be seen that the chlorin hemoglobin embedded manganese iron oxide electrode has good oxidation effect on ascorbic acid, and the catalytic oxidation performance of the electrode on ascorbic acid is better than that of the graphite electrode.

[0041] Example 3: Electro-catalytic oxidation of ascorbic acid to promote hydrogen production

[0042] The chlorin hemoglobin embedded manganese iron oxide electrode prepared in Example 1 was used as the working electrode, the titanium wire was used as the counter electrode, the saturated calomel electrode (SCE) was used as the reference electrode, 25 mL of 0.1 mol / L sodium sulfate solution (supporting electrolyte) and 0.02 mol / L ascorbic acid solution were added to the anode chamber, and 0.1 mol / L sodium sulfate electrolyte solution was added to the cathode chamber, and a three-electrode electrochemical reaction system was constructed, wherein the cathode chamber was provided with a 2 mL glass tube with scale, and the scale on the glass tube was read by using the air exhaust method, so as to obtain the volume of hydrogen produced on the titanium wire as the counter electrode. When the chlorin hemoglobin embedded manganese iron oxide electrode was applied with a bias of 0.5V (vs. SCE) for 1000 seconds, the hydrogen production volume-time curve was recorded, as shown in Figure 3 . When the bias of 0.5V (vs. SCE) was applied for 1000 seconds, 0.8 mL of hydrogen was produced on the counter electrode, and the hydrogen production effect was very good. At the same time, hydrogen production was realized under a lower bias, and it can be seen that the electro-catalytic oxidation of ascorbic acid by the chlorin hemoglobin embedded manganese iron oxide electrode has a good promoting effect on hydrogen production.

[0043] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement manners and should be included in the protection scope of the present application.

Claims

1. A method for preparing a chlorinated heme intercalated manganese iron oxide electrode, characterized by It comprises the following steps: (1) A sodium sulfate solution with a concentration of 0.1 mol / L is used as a supporting electrolyte, and manganese sulfate, ferrous sulfate and hemin are added to prepare an electroplating solution, wherein the concentrations of manganese sulfate and ferrous sulfate in the electroplating solution are both 0.001-0.01 mol / L, and the concentration of hemin in the electroplating solution is 0.03-0.1 mmol / L; (2) A graphite substrate is immersed in the electroplating solution as a working electrode, a titanium sheet is used as a counter electrode, and a saturated calomel electrode is used as a reference electrode to construct a three-electrode system, the temperature range for electrodeposition is controlled to be 15-30°C, and a continuous cyclic voltammetry method is used to deposit manganese-iron oxides on the surface of the graphite substrate through multiple cathodic deposition and anodic oxidation, and in the continuous circulation process, hemin is also adsorbed and embedded in the manganese-iron oxides to form a composite electrode of metal oxides and complexes; (3) The composite electrode of metal oxides and complexes prepared in step (2) is subjected to constant-temperature drying treatment to obtain a hemin-embedded manganese-iron oxide electrode.

2. The method for preparing a chlorinated hematin intercalated manganese-iron oxide electrode according to claim 1, characterized by: The molar ratio of manganese to iron in the plating solution of step (1) is 1:1; the surface size of the graphite substrate involved in the deposition of step (2) is 0.5-5 cm 2 .

3. The method for preparing a heme chloride-embedded manganese iron oxide electrode according to claim 1, characterized in that: The potential range of the cyclic voltammetry deposition in step (2) is -0.8-1.4 V, the deposition number is 5-40, and the scanning speed is 0.05 V s -1 .

4. The method of claim 1, wherein the method comprises: The temperature for the constant-temperature drying in step (3) is 30-50°C.

5. A hemin-embedded manganese-iron oxide electrode prepared by the preparation method in any one of claims 1-4.

6. Application of the hemin-embedded manganese-iron oxide electrode in claim 5 as a working electrode in electrocatalytic oxidation of ascorbic acid.

7. Use according to claim 6, characterized in that: The application comprises the following steps: a mixed solution of sodium sulfate and ascorbic acid is used as an anode chamber solution, and a sodium sulfate solution is used as a cathode chamber solution; the hemin-embedded manganese-iron oxide electrode is used as a working electrode, a titanium wire is used as a counter electrode, and a saturated calomel electrode is used as a reference electrode to construct a three-electrode system, and a chronoamperometry method is used to apply a bias voltage to the system to realize the oxidation of ascorbic acid and promote the production of hydrogen.

8. Use according to claim 7, characterized in that: The concentration of sodium sulfate in the anode chamber solution is 0.1 mol / L, and the concentration of ascorbic acid is 0.001-0.1 mol / L; the concentration of the sodium sulfate solution in the cathode chamber solution is 0.1 mol / L.

9. Use according to claim 7, characterized in that: A 2-mL glass tube with scales is installed in the cathode chamber, and the scales of the glass tube are read by using the air displacement method to obtain the volume of hydrogen produced; The bias voltage range of the chronoamperometry method is 0.4-1.0 V.

10. Use according to claim 9, characterized in that: The bias voltage of the chronoamperometry method is 0.5 V.

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