A method for real-time detection of photocatalytic water decomposition reaction products based on a dual-channel electrode

Abstract

The application provides a product real-time detection method for a photocatalytic water decomposition reaction based on a double-channel electrode, utilizes the prepared double-channel electrode, and can synchronously perform photocatalytic reaction and product detection during detection, can effectively transmit substances during the photocatalytic reaction and the product detection process, and guarantees the real-time and accuracy of detection. In addition, the double-channel electrode structure used in the application guarantees that the substance transmission mode on the surfaces of the two working electrodes is realized by spontaneous diffusion, avoids the generation of noise caused by external disturbance, and thus realizes the real-time monitoring target of the reaction product in the solution to be detected. The application can perform real-time detection on the generated product gas molecules in the initial stage of the photocatalytic reaction, greatly reduces the detection blind area. The real-time detection method of the application has a wide application range and can be used for the real-time detection of the products of photocatalytic reactions driven by various photocatalysts.

Description

Technical Field

[0001] This invention belongs to the technical field of electrochemical detection, specifically relating to a real-time detection method for photocatalytic water splitting reaction products based on a dual-channel electrode. Background Technology

[0002] Hydrogen energy is a highly efficient and environmentally friendly renewable energy source, while fuel cells, as a new way of utilizing clean energy such as hydrogen and oxygen, have the advantages of high energy utilization and low environmental pollution, and are a potential alternative to traditional energy use methods such as burning coal and oil. Furthermore, the photoelectrocatalytic decomposition of water to produce hydrogen and oxygen using sunlight provides a highly promising option for the preparation and development of clean energy.

[0003] Research on photocatalytic water splitting for hydrogen and oxygen production largely focuses on the development and characterization of novel catalysts, as well as the exploration of reaction mechanisms. These two aspects complement each other: catalyst characterization facilitates the study of reaction mechanisms, while the study of mechanisms, in turn, promotes the design and development of novel catalysts. In the search for inexpensive and efficient photocatalytic hydrogen or oxygen production catalysts, researchers have turned their attention to numerous elements and compounds, such as sulfides, selenides, metal oxides, and non-metallic nitrides, all of which have been used as photocatalysts for hydrogen and oxygen production reactions.

[0004] Typically, in studies of catalysts and catalytic mechanisms, the description and evaluation of catalyst performance are mainly based on parameters such as photocurrent density and photoelectric conversion efficiency. Meanwhile, the quantitative determination of products such as hydrogen and oxygen generated during the catalytic reaction is primarily accomplished using gas chromatography. However, gas chromatography has a certain testing blind spot. Specifically, in the initial stages of the reaction or at stages with low product yields (i.e., before the reaction products have formed bubbles and escaped), the concentration of gaseous product molecules is low and they have not yet dissolved, failing to form bubbles to escape from the reaction solution. Therefore, quantitative analysis using gas chromatography is not possible. In other words, traditional product detection methods still have limitations in tracking the generation process of gaseous products during the reaction. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a method for real-time detection of photocatalytic water splitting reaction products based on a dual-channel electrode. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] This invention provides a method for real-time detection of photocatalytic water splitting reaction products based on a dual-channel electrode, comprising:

[0007] S100, Select the already prepared dual-channel electrode; the dual-channel electrode includes a generating electrode and a collecting electrode, and a dual-channel electrode is formed between the generating electrode and the collecting electrode;

[0008] S200, the generating electrode, collecting electrode, reference electrode and counter electrode are all placed in the aqueous solution to be detected;

[0009] S300, ultraviolet light is used to irradiate the generating electrode located in the aqueous solution, so that the compound on the generating electrode reacts with the reactants in the aqueous solution under the action of light; and an electric potential is applied to the collecting electrode, so that the collecting electrode reacts according to the substances generated by the reaction of the generating electrode to generate current;

[0010] S400, the current is collected synchronously using the collecting electrode to achieve synchronous detection of the photocatalytic water splitting reaction products for oxygen or hydrogen production in the aqueous solution to be detected.

[0011] Beneficial effects:

[0012] This invention provides a real-time detection method for photocatalytic water splitting reaction products based on a dual-channel electrode. The fabricated dual-channel electrode can perform both photocatalytic reaction and product detection during the process, effectively transporting substances and ensuring real-time and accurate detection. Furthermore, the dual-channel electrode structure ensures that the substance transport between the two working electrode surfaces is achieved through spontaneous diffusion, avoiding noise generation caused by external disturbances, thus achieving the goal of real-time monitoring of reaction products in the aqueous solution. This invention enables real-time detection of the generated product gas molecules at the very initial stage of the photocatalytic reaction, significantly reducing the detection blind zone. The real-time detection method of this invention has a wide range of applications and can be used for the real-time detection of photocatalytic reaction products driven by various photocatalysts.

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic flowchart of a real-time detection method for photocatalytic water splitting reaction products based on dual-channel electrodes provided by the present invention.

[0015] Figure 2 This is a schematic diagram of the fabrication process of the dual-channel electrode provided by the present invention;

[0016] Figure 3 A comparison of single-electrode cyclic voltammetry curves of carbon material films prepared under reducing atmospheres with different hydrogen contents in solutions containing 0.1 mmol / L potassium ferricyanide and 0.1 mol / L potassium chloride;

[0017] Figure 4 This is a schematic diagram of catalyst modification on the surface of a carbon material electrode.

[0018] Figure 5This is a schematic diagram of a method for detecting the products of photocatalytic water splitting reaction using a dual-channel working electrode. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0020] Combination Figures 1 to 5 This invention provides a method for real-time detection of photocatalytic water splitting products based on a dual-channel electrode, comprising:

[0021] S100, select the already prepared dual-channel electrode;

[0022] refer to Figure 2 The dual-channel electrode includes a generating electrode and a collecting electrode, forming a dual-channel electrode between the generating electrode and the collecting electrode; the dual-channel electrode is in the form of an interdigitated array, a polygonal array, a dotted array, etc. The minimum spacing between the two working electrodes ranges from 0.5 μm to 10 μm, see Appendix. Figure 2 .

[0023] This invention enables cyclic voltammetry detection, with a potential scan range of 0.4V to 0V. The reference electrode is Ag / AgCl, and the counter electrode is a carbon rod. The cyclic voltammetry is used to verify whether the prepared carbon material dual working electrode has good conductivity.

[0024] Specifically, the fabrication process of the dual-channel electrode in S100 includes:

[0025] (1) Design a dual-channel working electrode pattern on a substrate such as silicon oxide or quartz;

[0026] (2) Using the dual-channel working electrode to design a pattern, a photoresist pattern of the dual-channel working electrode is prepared on an insulating substrate, and the photoresist pattern is calcined at high temperature in a reducing atmosphere to obtain a dual-channel working electrode of carbon material.

[0027] refer to Figure 3 , Figure 3 A comparison of single-electrode cyclic voltammetry curves of carbon material films prepared under reducing atmospheres with different hydrogen contents, measured in solutions containing 0.1 mmol / L potassium ferricyanide and 0.1 mol / L potassium chloride. The reducing atmosphere in this invention is a mixture of 4% H₂ and 96% Ar.

[0028] It is worth noting that, in order to improve the conductivity of the carbon structure as an electrode material, the optimal proportion of hydrogen in the reducing atmosphere is 4% (v / v).

[0029] (3) A photocatalyst is modified on the surface of the generating electrode in the active region of the dual-channel working electrode so that the dual-channel working electrode has the ability to photocatalytically split water, and an oxygen reduction reaction active catalyst is modified on the surface of the collecting electrode in the active region of the dual-channel working electrode so that the dual-channel working electrode has the ability to detect oxygen.

[0030] refer to Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of catalyst modification on the surface of a carbon material electrode. Figure 5 This is a schematic diagram of a method for detecting the products of photocatalytic water splitting using a dual-channel working electrode. In this invention, titanium dioxide, zinc oxide, or other photocatalyst particles are deposited on the generating electrode of the dual-channel working electrode via electrophoresis. These other photocatalyst particles can be strontium titanate, tantalum pentoxide, bismuth vanadate, zinc sulfide, cadmium sulfide, etc., enabling the dual-channel working electrode to perform photocatalytic water splitting. On the collecting electrode of the dual-channel working electrode, platinum or other active material particles are modified via electrodeposition. These active material particles can be palladium, gold, etc., enabling the dual-channel working electrode to detect oxygen or hydrogen. The modification of the active material on the electrode surface using electrodeposition or electrophoresis is relatively simple and easy to perform.

[0031] In principle, the special structural features of the micron-scale dual-channel working electrode ensure that "photocatalytic reaction" and "product detection" can be carried out simultaneously in both principle and device configuration. That is, photocatalytic reaction and product detection reaction can be carried out simultaneously in a tiny area.

[0032] Structurally, the dual-channel working electrode used in this invention consists of two sets of relatively small (minimum size on the micrometer scale) working electrodes. This special structure ensures effective mass transfer between the "occurrence of photocatalytic reaction" and "product detection," while also giving the detection method advantages such as small size and low consumption. Both interdigitated arrays and polygonal arrays can achieve this "real-time detection" function, thus providing multiple options for electrode fabrication.

[0033] S200, the generating electrode, collecting electrode, reference electrode and counter electrode are all placed in the aqueous solution to be detected;

[0034] In an aqueous solution, a photocatalytic water splitting reaction occurs. The current on the collecting electrode can be either a reduction current or an oxidation current. If the reaction is a photocatalytic water splitting reaction to produce oxygen, the current on the collecting electrode is a reduction current, and the potential of the collecting electrode is set to -0.5V. If the reaction is a photocatalytic water splitting reaction to produce hydrogen, the current on the collecting electrode is an oxidation current, and the potential of the collecting electrode is set to -0.1V.

[0035] In this invention, the generating electrode, collecting electrode, reference electrode, and counter electrode are all placed in an aqueous solution filled with nitrogen gas, which is a 0.1 mol / L sodium sulfate aqueous solution.

[0036] The carbon rod counter electrode and the Ag / AgCl reference electrode are both existing electrodes.

[0037] S300, the generating electrode located in an aqueous solution passing through nitrogen gas is irradiated with ultraviolet light, so that the compound on the generating electrode reacts with the reactants in the aqueous solution under the action of light; and an electric potential is applied to the collecting electrode, so that the collecting electrode reacts with the substances generated by the reaction of the generating electrode, thereby generating an electric current.

[0038] This invention places the modified dual-channel working electrode in a reaction solution. Under light conditions and appropriate potential, a photocatalytic water splitting reaction occurs on the electrode surface, and the product molecules generated can be detected in real time by collecting the electrode surface.

[0039] Specifically, the S300 includes:

[0040] S310 periodically irradiates the surface of the generating electrode with ultraviolet light of wavelength 365nm and power of 5W, so that the catalyst particles on the generating electrode react with the aqueous solution under photocatalysis to generate O2 or H2.

[0041] Further, S310 includes:

[0042] S311 involves irradiating the surface of the generating electrode with ultraviolet light of 365 nm wavelength and 5 W power, causing the catalyst particles on the generating electrode to react with the aqueous solution under photocatalysis to generate O2 or H2. This invention utilizes linear sweep voltammetry for detection. For the detection of the photocatalytic water splitting reaction to produce oxygen, the scanning range of the linear sweep voltammetry is 0 V to 0.7 V; for the detection of the photocatalytic water splitting reaction to produce hydrogen, the scanning range of the linear sweep voltammetry is -0.7 V to 0 V. The reference electrode is Ag / AgCl, and the counter electrode is a carbon rod.

[0043] In S312, in order to visually observe the detection of photocatalytic products on the generating electrode by the collecting electrode, the light source is periodically blocked to periodically excite the photocatalytic reaction and repeat the process of S311 to periodically generate O2 or H2 forming current.

[0044] S320, depending on the different situations in which O2 or H2 is generated by the generating electrode, a corresponding potential is applied to the surface of the collecting electrode synchronously with the illumination of the light source, so that the collecting electrode reacts accordingly to O2 or H2, thereby generating a corresponding current.

[0045] If the generating electrode reacts under photocatalysis to generate O2, a potential of -0.5V is applied to the surface of the collecting electrode simultaneously with the irradiation of the light source, so that the collecting electrode reduces the generated O2, thereby generating a reduction current.

[0046] If the generating electrode reacts under photocatalysis to generate H2, a potential of -0.1V is applied to the surface of the collecting electrode simultaneously with the light source irradiation, so that the collecting electrode oxidizes the generated H2, thereby generating an oxidation current.

[0047] S400, the current is collected synchronously using the collecting electrode to achieve synchronous detection of the photocatalytic water splitting reaction products for oxygen or hydrogen production in the aqueous solution to be detected.

[0048] refer to Figure 4 and Figure 5 The present invention utilizes the collecting electrode to synchronously and periodically collect the reduction current, thereby achieving synchronous detection of the photocatalytic decomposition of water to produce oxygen or hydrogen in the aqueous solution to be detected.

[0049] In terms of detection performance, the minimum spacing between the working electrodes used in this invention can be 0.5 μm to 10 μm. This electrode size ensures that the mass transport between the two working electrode surfaces is achieved through spontaneous diffusion, thus avoiding the forced convection mass transport method used in traditional electrochemical detection methods (such as the rotating ring-disc electrode method). This also avoids noise generation caused by external disturbances, thereby achieving the goal of real-time monitoring of the reaction products. The smaller the electrode size, the more efficient the mass transport and the higher the detection sensitivity. Compared with traditional gas chromatography detection methods, this method can detect the generated product gas molecules in real time at the very initial stage of the photocatalytic reaction, greatly reducing the detection blind zone.

[0050] This invention provides a real-time detection method for photocatalytic water splitting products based on a dual-channel electrode. This detection method has a wide range of applications and can be used for real-time detection of photocatalytic reaction products driven by various photocatalysts. The equipment used in this method is relatively simple, the detection method is easy to operate, highly feasible, not easily damaged, and easy to maintain. The required equipment is small in size and has good portability.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0052] Although this application has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the appended claims in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality.

[0053] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for real-time detection of photocatalytic water decomposition reaction products based on a dual-channel electrode, characterized in that, include: S100, select the already prepared dual-channel electrode; The dual-channel electrode includes a generating electrode and a collecting electrode, and a dual-channel electrode is formed between the generating electrode and the collecting electrode. S200, the generating electrode, collecting electrode, reference electrode and counter electrode are all placed in the aqueous solution to be detected; S300, ultraviolet light is used to irradiate the generating electrode located in the aqueous solution, so that the compound on the generating electrode reacts with the reactants in the aqueous solution under the action of light; and an electric potential is applied to the collecting electrode, so that the collecting electrode reacts according to the substances generated by the reaction of the generating electrode to generate current; S400, the current is collected synchronously using the collecting electrode to achieve synchronous detection of the photocatalytic water splitting reaction products for oxygen or hydrogen production in the aqueous solution to be detected.

2. The method according to claim 1, wherein the method is characterized by, The dual-channel electrodes are in the form of any one of interdigital array, polygonal array, or dot array; the minimum spacing between the two working electrodes ranges from 0.5 µm to 10 µm. 3.The method according to claim 1, wherein, S200 includes: The generating electrode, collecting electrode, reference electrode, and counter electrode were all placed in a 0.1 M sodium sulfate aqueous solution passing nitrogen gas. 4.The method according to claim 1, wherein, The S300 includes: S310 periodically irradiates the surface of the generating electrode with ultraviolet light of wavelength 365 nm and power of 5 W, so that the catalyst particles on the generating electrode react with the aqueous solution under photocatalysis to generate O2 or H2. S320, depending on the different situations in which O2 or H2 is generated by the generating electrode, a corresponding potential is applied to the surface of the collecting electrode synchronously with the illumination of the light source, so that the collecting electrode reacts accordingly to O2 or H2, thereby generating a corresponding current.

5. The method according to claim 4, wherein the method is characterized by, S310 includes: S311 uses a 365 nm wavelength, 5 W ultraviolet light source to irradiate the surface of the generating electrode, causing the catalyst particles on the generating electrode to react with the aqueous solution under photocatalysis to generate O2 or H2. S312 periodically blocks the light source to periodically excite the photocatalytic reaction and repeats the process of S311 to periodically generate O2 or H2 to form an electric current. 6.The method according to claim 4, wherein, S320 includes: If the generating electrode reacts under photocatalysis to generate O2, a potential of -0.5 V is applied to the surface of the collecting electrode simultaneously with the light source irradiation, so that the collecting electrode reduces the generated O2, thereby generating a reduction current. If the generating electrode reacts under photocatalysis to generate H2, a potential of -0.1V is applied to the surface of the collecting electrode simultaneously with the light source irradiation, so that the collecting electrode oxidizes the generated H2, thereby generating an oxidation current.

7. The method according to claim 1, wherein the method is characterized by, The S400 includes: By using the collecting electrode to collect the current synchronously and periodically, the photocatalytic decomposition of water to produce oxygen or hydrogen in the aqueous solution to be tested can be detected simultaneously.

8. The method according to claim 1, wherein the method is characterized by, The fabrication process of the dual-channel electrode in S100 includes: (1) Design a dual-channel working electrode pattern on a substrate such as silicon oxide or quartz; (2) Using the design pattern of the dual-channel working electrode, a photoresist pattern of the dual-channel working electrode is prepared on an insulating substrate, and the photoresist pattern is calcined at high temperature in a reducing atmosphere to obtain a dual-channel working electrode of carbon material. (3) A photocatalyst is modified on the surface of the generating electrode in the active region of the dual-channel working electrode so that the dual-channel working electrode has the ability to photocatalytically split water, and an oxygen reduction reaction active catalyst is modified on the surface of the collecting electrode in the active region of the dual-channel working electrode so that the dual-channel working electrode has the ability to detect oxygen. 9.The method of claim 8, wherein the method is characterized by, (2) The reducing atmosphere is a mixture of 4% H2 and 96% Ar. 10.The method of claim 8, wherein the method is characterized by, (3) includes: depositing titanium dioxide, zinc oxide, or other photocatalyst particles on the generating electrode of the dual-channel working electrode by electrophoresis, so that the dual-channel working electrode has the ability to photocatalytically split water; modifying the collecting electrode of the dual-channel working electrode with metal platinum or other active material particles by electrodeposition, so that the dual-channel working electrode has the ability to detect oxygen or hydrogen; wherein, the other photocatalyst particles include strontium titanate, tantalum pentoxide, bismuth vanadate, zinc sulfide, and cadmium sulfide, and the other active material particles include metal palladium and metal gold.

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