Preparation method and application of carbon nitride-based photoelectrode with ordered phase structure
By using electrophoresis and electrochemical deposition methods to construct a carbon nitride-based photoelectrode with an ordered phase structure in photoelectrochemical biosensing, the thermodynamic and grain boundary effects problems of carbon nitride-based photoelectrode preparation in traditional methods are solved, and the problem of High sensitivity and high selectivity photoelectric sensing overcomes the thermodynamic and grain boundary effects of traditional methods and improves the sensitivity and selectivity of detection.
Patent Information
- Application Number
- CN202310824221.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-05
- Publication Date
- 2025-01-07
AI Technical Summary
The prior art is difficult to prepare carbon nitride-based photoelectrodes with different orders, resulting in insufficient detection selectivity and sensitivity in photoelectrochemical biosensing. Traditional methods are limited by thermodynamics and grain boundary effects, and cannot achieve uniform and tightness. The carbon nitride-based electrode is in contact with the substrate.
By placing the bulk carbon nitride material in an organic solvent, and then dispersing it in protonation, carbon nitride and bismuth iodate are deposited on the substrate electrode by electrophoretic deposition and electrochemical deposition methods, the deposition sequence is adjusted to construct an ordered phase The structured carbon nitride-based photoelectrode overcomes the thermodynamic and grain boundary effects of the traditional method and achieves uniform and dense photoelectrode preparation.
The charge migration direction regulation of carbon nitride materials is realized, the sensitivity and selectivity of photoelectric sensing are improved, the preparation process is simplified, the thermodynamic limitations under high temperature conditions is avoided, and the deposition time is short, the equipment is simple, and the magnification is easy.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of material chemistry, and in particular relates to a preparation method and application of a carbon nitride-based photoelectrode with an ordered phase structure. Background Art
[0002] Carbon nitride has the advantages of strong visible light absorption (up to 460nm), photochemical stability, low cost and easy preparation, and suitable oxidation and reduction potentials, and is widely used in research in the fields of photocatalytic pollutant degradation, photoelectric biosensing, and solar fuel conversion. In photoelectrochemical biosensing, the separation and transfer of photogenerated carriers play a very important role in sensing. Different charge transfer pathways can bring about rich sensor signal changes and improve detection selectivity and sensitivity. In theory, based on the built-in electric field built in the heterostructure, different semiconductors can be assembled layer by layer and the assembly order can be adjusted to adjust the transmission direction of electrons or holes and construct rich charge transfer pathways. Therefore, constructing carbon nitride-based photoelectrodes with ordered phase structures of different orders is the key to promoting photoelectrochemical sensing. The characteristics of cheapness and stability have aroused great interest in fields from artificial photosynthesis to photoelectric sensing. However, it is still challenging to construct carbon nitride-based photoelectrodes with ordered phase interfaces of different orders and controllable charge migration directions. This may be due to the thermodynamic limitations of the volatilization of precursors in situ thermal condensation in traditional electric furnaces, and the weak adhesion of bulk carbon nitride on the substrate electrode caused by the grain boundary effect caused by common deposition techniques such as drop coating and doctor blade method. These methods cannot achieve alternating assembly of carbon nitride-based photoelectrodes. Therefore, it is of great significance to develop a preparation method for carbon nitride-based photoelectrodes with an ordered phase structure. Summary of the invention
[0003] Purpose of the invention: In view of the problems existing in the prior art, the present invention provides a carbon nitride-based photoelectrode with an ordered phase structure. The method of the present invention can prepare a carbon nitride-based photoelectrode with an ordered phase structure of different orders. The present invention effectively solves the problem of difficulty in preparing a uniform carbon nitride-based photoelectrode that is in close contact with a substrate through an electrochemical method, and provides a new detection mode for photoelectrochemical biosensing.
[0004] The present invention also provides a carbon nitride-based photoelectrode prepared by the method for preparing the carbon nitride-based photoelectrode with an ordered phase structure and applications thereof.
[0005] Technical solution: In order to achieve the above-mentioned purpose, the method for preparing a carbon nitride-based photoelectrode with an ordered phase structure described in the present invention comprises the following steps:
[0006] (1) placing a bulk carbon nitride material in an organic solvent for ultrasonic dispersion, and centrifuging and collecting the supernatant to obtain a carbon nitride dispersion;
[0007] (2) protonating the carbon nitride dispersion obtained in step (1) with an acid and depositing the protonated carbon nitride dispersion onto a substrate electrode by electrophoretic deposition;
[0008] (3) calcining the electrode obtained in step (2), depositing bismuth iodate on the surface of the electrode by an electrochemical deposition method, and calcining to obtain a photoelectrode having a carbon nitride-bismuth iodate ordered phase structure;
[0009] (4) Alternatively, the order of electrophoretic deposition and electrochemical deposition in step (2) and step (3) is adjusted, and bismuth iodate is first deposited on the electrode surface by electrochemical deposition, and then calcined; the carbon nitride dispersion is protonated with hydroiodic acid, and then deposited on the calcined electrode by electrophoretic deposition, and then calcined to obtain a photoelectrode with a different ordered phase structure.
[0010] Wherein, the carbon nitride material in step (1) is g-C3N4 or C3N2.
[0011] Wherein, the organic solvent in step (1) includes any one of acetone, isopropanol, ethanol or 1,3-butanediol.
[0012] Wherein, the acid in step (2) is hydroiodic acid, dilute hydrochloric acid or dilute sulfuric acid, preferably hydroiodic acid.
[0013] Wherein, the power source for the electrophoretic deposition in step (2) is a direct current power source, the voltage is 5V-150V, and the deposition time is 0.5 minutes-120 minutes.
[0014] Wherein, the substrate electrode in step (2) is a fluorine-doped indium tin oxide (FTO) electrode.
[0015] Wherein, the calcination in step (3) is to increase the temperature to 150°C-350°C at a rate of 2°C / min-20°C / min and maintain the temperature for 0.5 hour-5 hours.
[0016] Wherein, the electrochemical deposition in step (3) is performed by chronoamperometry or cyclic voltammetry, with a potential of -1V-0V and a deposition time of 0.5 minutes-30 minutes.
[0017] The ratio of carbon nitride, hydroiodic acid and bismuth iodate is controlled by deposition time.
[0018] The carbon nitride-based photoelectrode prepared by the method for preparing the carbon nitride-based photoelectrode with an ordered phase structure described in the present invention.
[0019] Application of the carbon nitride-based photoelectrode described in the present invention in the preparation of a photoelectrochemical sensor.
[0020] The method for preparing the carbon nitride-based photoelectrode with an ordered phase structure described in the present invention prepares carbon nitride-based photoelectrodes with different ordered phase structures, and is applied in regulating the charge migration direction of carbon nitride material photoelectrochemical biosensing.
[0021] Furthermore, the preparation method of the present invention can prepare a multilayer structure, such as CN-BiOI-CN-BiOI, which can change the photocurrent and the response mode to the target object, and further realize the regulation of the charge migration direction of the carbon nitride material.
[0022] The present invention proposes a new method for preparing a carbon nitride-based photoelectrode with an ordered phase structure, wherein the bulk carbon nitride material is ultrasonically dispersed in an organic solvent, and the supernatant is centrifuged to obtain a carbon nitride dispersion; the carbon nitride is protonated with hydroiodic acid, and the carbon nitride is deposited on a base electrode by electrophoretic deposition; bismuth iodate is deposited on the obtained electrode by electrochemical deposition to obtain a photoelectrode with a carbon nitride-bismuth iodate ordered phase structure; and the deposition order of the above two materials can be adjusted to obtain a bismuth iodate-carbon nitride photoelectrode with a sequential ordered phase structure. The above method for preparing a carbon nitride-based photoelectrode with an ordered phase structure is simple to operate, and the prepared carbon nitride-based photoelectrode has a different ordered phase structure, which can be effectively applied to fields such as photoelectrochemical sensing, and is conducive to the study of phase interfaces and electron transfer in photoelectric sensing.
[0023] The present invention is based on the principles of type II heterojunction and Z-type heterojunction. By adjusting the assembly order of optoelectronic materials with different energy level structures, different heterostructures are constructed to achieve the regulation of phase interface and charge migration direction. Although the preparation of photoelectrodes with ordered phase structures has been reported in the energy field, its main purpose is to maximize the charge separation efficiency, thereby obtaining the maximum energy conversion efficiency. However, from the perspective of signal conduction, the most important thing is how to use the detection target to interact with the photogenerated charge, thereby causing a change in the signal. Because different charge migration directions will cause different interactions between the charge and the detection target, resulting in different signal changes, regulating the charge migration direction is an important means to enrich photoelectrochemical sensing. On the basis of achieving the regulation of the phase interface and charge migration direction, the present invention has developed a new photoelectric sensing mode, which greatly improves the sensing sensitivity and selectivity.
[0024] The present invention focuses on the regulation of the charge migration direction by preparing carbon nitride-based photoelectrodes with different ordered phase structures, and on this basis develops a photoelectric sensing mode with high sensitivity and selectivity. In terms of electrode preparation, compared with the traditional electric furnace in-situ thermal condensation precursor method or drip coating method, scraper method, etc., the present invention overcomes the thermodynamic limitations and grain boundary effects in traditional methods, and achieves the preparation of uniform, dense, ordered phase structure photoelectrodes under mild conditions. In terms of photoelectric biosensing, traditional photoelectrochemical biosensors have the advantage of high selectivity, but their detection process requires complex biological reaction steps, and the application conditions are harsh, with high requirements for the environment, temperature, etc. The present invention can achieve high sensitivity and high selectivity detection of the target object by regulating the charge migration direction.
[0025] Beneficial effects: Compared with the prior art, the present invention has the following advantages:
[0026] The present invention proposes a method for preparing a carbon nitride-based photoelectrode with an ordered phase structure. The preparation process is based on mild electrophoretic deposition and electrochemical deposition methods, is not limited by thermodynamics and grain boundary effects, has the advantages of short deposition time, few substrate shape restrictions, simple deposition equipment, and easy amplification. The prepared carbon nitride-based photoelectrode with an ordered phase structure of different orders is uniform and dense, and the regulation of the charge transfer pathway is achieved. On this basis, a photoelectric sensing mode with high sensitivity and high selectivity is developed. The material prepared by the present invention has high sensitivity and, more importantly, very good selectivity, while the current carbon nitride is not selective under conditions without biological modification. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 X-ray diffraction patterns of FTO, bulk CN (PCN), FTO / CN, FTO / BiOI, FTO / CN / BiOI, and FTO / BiOI / CN; wherein, FTO is a fluorine-doped indium tin oxide electrode, bulk CN (PCN) is g-C3N4 prepared from melamine in step (1) of Example 1, FTO / CN is a carbon nitride photoelectrode prepared in step (5) of Example 1, FTO / BiOI is a bismuth iodate photoelectrode prepared in step (5) of Example 2, FTO / CN / BiOI is a photoelectrode of a carbon nitride-bismuth iodate ordered phase structure prepared in step (7) of Example 1, and FTO / BiOI / CN is a photoelectrode of a bismuth iodate-carbon nitride ordered phase structure prepared in step (7) of Example 2;
[0028] Figure 2 Infrared spectra of FTO, bulk CN (PCN), FTO / CN, FTO / BiOI, FTO / CN / BiOI, and FTO / BiOI / CN;
[0029] Figure 3 Cross-sectional scanning electron micrographs of (a) FTO / CN / BiOI and (b) FTO / BiOI / CN electrodes;
[0030] Figure 4 The photoampere-to-chopper curves of FTO / CN, FTO / BiOI, FTO / CN / BiOI, and FTO / BiOI / CN electrodes are shown in Figure 1. The supporting electrolyte is 0.1 M KCl, and the applied bias voltage is -0.2 V to 0.6 V (relative to Ag / AgCl electrode).
[0031] Figure 5 UV-visible diffuse reflectance spectra of CN (a) and BiOI (b);
[0032] Figure 6 Photocurrent response curves of FTO / CN (a) and FTO / CN / BiOI (b) for testing different concentrations of AA, (c) is the schematic diagram of differential signal processing of FTO / CN and FTO / CN / BiOI, and (d) is the differential signal fitting curve;
[0033] Figure 7 These are the photocurrent response results of FTO / CN, FTO / CN / BiOI, and FTO / BiOI / CN to 1 mM different test substances (AA, DA, GSH, EP, CA), where "+" indicates signal increase and "-" indicates signal decrease. Using the above electrodes to detect different target substances (common antioxidants), the response result of AA is a unique "+-+", which can be completely distinguished from other common antioxidants, proving that this method can specifically distinguish different target molecules without using any surface modification. DETAILED DESCRIPTION
[0034] The present invention is further described below in conjunction with the accompanying drawings and embodiments.
[0035] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources. Experimental methods without specific conditions specified in the examples are usually carried out under conventional conditions or under conditions recommended by the manufacturer.
[0036] The preparation method of the carbon nitride prepared in the present invention is as follows: 10 g of dicyandiamide is weighed in a 30 mL crucible, the temperature is raised to 550° C. in a muffle furnace for 4 hours, the temperature is naturally lowered after being kept at the temperature for 4 hours, and g-C3N4 is obtained.
[0037] The method for preparing the precursor solution of bismuth iodate in the present invention comprises the following steps: 0.04M bismuth nitrate solution and 0.4M potassium iodide solution are mixed, the pH value is adjusted to 1.7 with nitric acid, and finally 0.23M p-benzoquinone ethanol solution is added.
[0038] The hydroiodic acid was purchased from Aladdin.
[0039] Example 1
[0040] A method for preparing a carbon nitride-based photoelectrode with an ordered phase structure, the specific operations are as follows:
[0041] (1) 150 mg of g-C3N4 prepared from dicyandiamide was weighed and placed in 50 mL of acetone for 24 hours. The resulting dispersion was centrifuged at 5000 rpm for 20 minutes.
[0042] (2) Pour off the solid precipitate and take the supernatant and repeat step (1) twice.
[0043] (3) Add 5uL of hydroiodic acid to the carbon nitride dispersion obtained in step (2) and shake evenly.
[0044] (4) Two FTO electrodes were inserted into the dispersion obtained in step (3), and a two-electrode system (two FTO electrodes were used as positive and negative electrodes, respectively) was used. A 10 V DC voltage was applied and electrophoretic deposition was performed for 10 minutes to obtain a carbon nitride photoelectrode (the material was deposited at the negative electrode).
[0045] (5) The carbon nitride photoelectrode obtained as the negative electrode in step (4) is placed in a muffle furnace, heated to 250° C. at a rate of 3° C. / min, maintained for 1 hour, and then naturally cooled to room temperature.
[0046] (6) The carbon nitride electrode obtained in step (5) was used as the working electrode, a three-electrode system was adopted, a platinum wire was used as the counter electrode, and Ag / AgCl (saturated KCl) was used as the reference electrode. It was inserted into the precursor solution of bismuth iodate, a constant potential of -0.1 V was applied, and the electrodeposition was performed for 45 seconds.
[0047] (7) placing the carbon nitride photoelectrode obtained in step (6) in a muffle furnace, heating the temperature to 250° C. at a rate of 3° C. / min, maintaining the temperature for 1 hour, and then naturally cooling the temperature to room temperature to obtain a photoelectrode having a carbon nitride-bismuth iodate ordered phase structure.
[0048] The X-ray diffraction patterns of the carbon nitride photoelectrode prepared in step (5) and the carbon nitride-bismuth iodate photoelectrode prepared in step (7) of this embodiment are as follows: Figure 1 As shown in Figure 2, due to the poor crystallinity of carbon nitride nanosheets, its characteristic diffraction peak cannot be observed, but through Figure 2 The infrared spectrum shows obvious characteristic peaks of carbon nitride, proving that the carbon nitride electrode was successfully prepared and maintained its original structure. Figure 1 The X-ray diffraction peak of carbon nitride-bismuth iodate can show obvious characteristic peaks of bismuth iodate, indicating that bismuth iodate has successfully grown on the surface of the carbon nitride electrode. Figure 1 , Figure 2Prove the successful assembly of the two materials (each material maintains its original crystal form and molecular structure during the assembly process without any changes). Figure 3 (a) The phase structure of carbon nitride and bismuth iodate on the carbon nitride-bismuth iodate electrode can be clearly seen. Figure 3 This shows that the present invention overcomes the traditional method and realizes the preparation of a photoelectrode with a uniform, dense and ordered phase structure under mild conditions.
[0049] Example 2
[0050] A method for preparing a carbon nitride-based photoelectrode with an ordered phase structure, the specific operations are as follows:
[0051] (1) 150 mg of g-C3N4 prepared from dicyandiamide was weighed and placed in 50 mL of acetone for 24 hours. The resulting dispersion was centrifuged at 5000 rpm for 20 minutes.
[0052] (2) Pour off the solid precipitate and take the supernatant and repeat step (1) twice.
[0053] (3) Add 5uL of hydroiodic acid to the carbon nitride dispersion obtained in step (2) and shake evenly.
[0054] (4) FTO was used as the working electrode, a three-electrode system was adopted, a platinum wire was used as the counter electrode, and Ag / AgCl (saturated KCl) was used as the reference electrode. It was inserted into the precursor solution of bismuth iodate, and a constant potential of -0.1 V was applied. The electrodeposition was performed for 45 seconds to obtain a bismuth iodate photoelectrode (the material was deposited on the working electrode).
[0055] (5) The photoelectrode obtained in step (4) was placed in a muffle furnace, heated to 250° C. at a rate of 3° C. / min, maintained for 1 hour, and then naturally cooled to room temperature.
[0056] (6) The bismuth iodate photoelectrode obtained in step (5) is inserted into the dispersion obtained in step (3) as the negative electrode, and another FTO electrode is taken as the positive electrode. A two-electrode system is used, a DC voltage of 10 V is applied, and electrophoretic deposition is performed for 10 minutes (the material is deposited at the negative electrode).
[0057] (7) placing the carbon nitride photoelectrode obtained as the negative electrode in step (6) in a muffle furnace, heating the temperature to 250° C. at a rate of 3° C. / min, maintaining the temperature for 1 hour, and then naturally cooling the temperature to room temperature to obtain a photoelectrode having a bismuth iodate-carbon nitride ordered phase structure.
[0058] The X-ray diffraction patterns of the bismuth iodate photoelectrode prepared in step (5) and the bismuth iodate-carbon nitride photoelectrode prepared in step (7) of this embodiment are as follows: Figure 1As shown, the characteristic peaks of bismuth iodate can be clearly seen, proving that the bismuth iodate electrode and bismuth iodate-carbon nitride electrode were successfully prepared and the original crystal structure was maintained; Figure 2 The infrared spectrum shows obvious characteristic peaks of carbon nitride, proving that the carbon nitride electrode was successfully prepared and maintained its original structure. Figure 1 , Figure 2 Prove the successful assembly of the two materials (each material maintains its original crystal form and molecular structure during the assembly process without any changes). Figure 3 (b) The phase structure of bismuth iodate and carbon nitride on the bismuth iodate-carbon nitride electrode can be clearly seen. Figure 3 This shows that the present invention overcomes the traditional method and realizes the preparation of a photoelectrode with a uniform, dense and ordered phase structure under mild conditions.
[0059] The photoelectrochemical test used a conventional three-electrode system: platinum wire was used as the counter electrode, Ag / AgCl (saturated KCl) was used as the reference electrode, and the carbon nitride-based electrodes prepared in Examples 1 and 2 were used as the working electrode. The light source was a 150 W xenon lamp, and the light intensity was controlled to be 1000 W / m 2 , where the net current is the difference between the photocurrent and the dark current. Figure 4 It is the photoelectric response diagram of the photoelectrodes prepared in Example 1 and Example 2. Due to the different assembly orders, the direction of charge migration is changed, so the carbon nitride-bismuth iodate photoelectrode and the bismuth iodate-carbon nitride photoelectrode show reducing and improving effects relative to the single bismuth iodate photoelectrode, further illustrating that the preparation method of the present invention can realize the regulation of the charge migration direction.
[0060] The UV-visible diffuse reflectance spectrum shows the response of the material to light of different wavelengths. The energy band width of the material can be obtained by calculation. The photoelectric ampere curve can be used to obtain the flat band potential of the material. The conduction band and valence band positions of the material can be determined based on the flat band potential and energy band width. Combined with the photocurrent results ( Figure 4 ) to determine the charge transfer mode between different materials. Figure 5 ) and the photovoltaic safety curve ( Figure 4 ) can determine the energy level positions of carbon nitride and bismuth iodate.
[0061] The electrode prepared by the present invention was used to measure the concentration of AA at 0, 0.01, 0.02, 0.05, 0.1, 0.5, 1, and 2 mM, 0.1 M KCl solution, the test voltage was 0.1 V vs Ag / AgCl, the above three-electrode mode was used, a 150 W xenon lamp was used as the light source, and the light intensity was controlled to 1000 W / m 2 ;like Figure 6As shown, by regulating the charge transfer pathway, the response of the carbon nitride-bismuth iodate electrode to AA is manifested as a signal reduction. Combined with the response of the carbon nitride electrode to AA as a signal enhancement, a signal differential detection mode is designed to improve the sensitivity of AA detection.
[0062] The present invention Figure 4 The photocurrent shows that the two assembly results lead to the enhancement and reduction of the photocurrent respectively. Figure 5 and Figure 6 The calculated energy level structure of the material can explain that the present invention forms two different heterojunctions, resulting in different directions of movement of photogenerated carriers, proving that the present invention successfully regulates the direction of charge transfer for the first time.
[0063] Carbon nitride, carbon nitride-bismuth iodate, and bismuth iodate-carbon nitride photoelectrodes with different charge transfer pathways were used to detect common antioxidants. The detection method was the same as that of AA. The detection substances included AA, DA, GSH, EP, and CA, and the concentration was 1mM. By analyzing the response results, the prepared carbon nitride-based photoelectrode had a unique "+-+" signal response result for AA, achieving specific recognition of AA. Figure 7 As shown, the electrodes are used to detect the same target. Due to the different charge transfer methods, the electrodes respond differently to the same target. Combining different response results can improve the detection sensitivity of the same target and avoid the occurrence of "false positives". In addition, in terms of photoelectric biosensing, traditional photoelectrochemical biosensors have the advantage of high selectivity, but their detection process requires complex biological reaction steps, and the application conditions are harsh, with high requirements on the environment, temperature, etc., while the present invention Figure 6 and 7 This shows that high-sensitivity and high-selectivity detection of the target object can be achieved by regulating the direction of charge migration.
Claims
1. A method for preparing a carbon nitride-based photoelectrode having an ordered phase structure, characterized in that: The steps include: (1) placing a bulk carbon nitride material in an organic solvent for ultrasonic dispersion, and centrifuging and collecting the supernatant to obtain a carbon nitride dispersion; (2) protonating the carbon nitride dispersion obtained in step (1) with an acid and depositing the protonated carbon nitride dispersion onto a substrate electrode by electrophoretic deposition; (3) calcining the electrode obtained in step (2), depositing bismuth iodate on the surface of the electrode by an electrochemical deposition method, and calcining to obtain a photoelectrode having a carbon nitride-bismuth iodate ordered phase structure; (4) Alternatively, the order of electrophoretic deposition and electrochemical deposition in step (2) and step (3) is adjusted, and bismuth iodate is first deposited on the electrode surface by electrochemical deposition, and then calcined; the carbon nitride dispersion is protonated with hydroiodic acid, and then deposited on the calcined electrode by electrophoretic deposition, and then calcined to obtain a photoelectrode with a different ordered phase structure.
2. The method for preparing a carbon nitride-based photoelectrode having an ordered phase structure according to claim 1, characterized in that: The carbon nitride material in step (1) is g-C3N4 or C3N2.
3. The method for preparing a carbon nitride-based photoelectrode having an ordered phase structure according to claim 1, characterized in that: The organic solvent in step (1) preferably includes any one of acetone, isopropanol, ethanol or 1,3-butanediol.
4. The method for preparing a carbon nitride-based photoelectrode having an ordered phase structure according to claim 1, characterized in that: The acid in step (2) is hydroiodic acid, dilute hydrochloric acid or dilute sulfuric acid.
5. The method for preparing a carbon nitride-based photoelectrode having an ordered phase structure according to claim 1, characterized in that: The power source for the electrophoretic deposition in step (2) is a direct current power source with a voltage of 5V-150V and a deposition time of 0.5 minutes-120 minutes.
6. The method for preparing a carbon nitride-based photoelectrode having an ordered phase structure according to claim 1, characterized in that: The substrate electrode in step (2) is a fluorine-doped indium tin oxide (FTO) electrode.
7. The method for preparing a carbon nitride-based photoelectrode having an ordered phase structure according to claim 1, characterized in that: The calcination in step (3) is to increase the temperature to 150°C-350°C at a rate of 2°C / min-20°C / min and maintain it for 0.5 hour-5 hours; the electrochemical deposition in step (3) is carried out by chronoamperometry or cyclic voltammetry, with a potential of -1V-0V and a deposition time of 0.5 minute-30 minutes.
8. A carbon nitride-based photoelectrode prepared by the method for preparing a carbon nitride-based photoelectrode with an ordered phase structure as claimed in claim 1.
9. Use of the carbon nitride-based photoelectrode according to claim 8 in the preparation of a photoelectrochemical sensor.
10. Application of the method for preparing the carbon nitride-based photoelectrode with an ordered phase structure as claimed in claim 1 in regulating the charge migration direction of carbon nitride-based photoelectrochemical biosensing.