Method for enhancing hydrogen evolution reaction efficiency of semiconductor photocatalyst through electric field

Abstract

The invention relates to a method for enhancing the hydrogen evolution reaction efficiency of a semiconductor photocatalyst through an electric field, belongs to the technical field of photochemistry, and particularly relates to a photochemical analysis technology. Aiming at the urgent need of studying the regulation effect of an electric field on photocatalytic HER, the uniform and parallel electric field perpendicular to the electrode plate is formed by applying the bias voltage, separation of photo-generated carriers of catalyst particles is promoted under the action of Coulomb force, the photocatalytic reaction efficiency is improved, and good practical application value is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic water dissociation, and in particular relates to a method for enhancing the catalytic activity of a semiconductor photocatalyst. The semiconductor photocatalyst is suitable for being used as a catalyst in a photocatalytic water dissociation reaction for hydrogen evolution reaction (HER). Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Photocatalytic water splitting to produce hydrogen is to use photocatalysts to absorb light energy and excite electrons, thereby promoting the decomposition reaction of water molecules. It is currently considered to be one of the most effective ways to solve the energy crisis and environmental problems. However, due to the low separation of photogenerated carriers, the photocatalytic efficiency is still not ideal. At present, some studies have achieved the improvement of carrier separation efficiency by establishing a built-in electric field, such as by constructing Schottky junctions, S-heterojunctions, homojunctions, and Z-heterojunctions. The application of external electric fields in the photocatalytic process is a more flexible and controllable strategy, which has attracted the attention of more and more researchers.

[0004] The paper "Enhanced Electric Field Assisted Photocatalytic Degradation of Organic Pollutants" discloses that granular TiO2 is used as a photocatalyst and the degradation of phenol solution is used as a model reaction, realizing a three-dimensional photoelectric combined catalytic reaction assisted by an electric field. The experiment found that under the same reaction conditions, the degradation rates of phenol in the electrolysis reaction and the photocatalytic reaction were 10% and 33.6%, respectively, while the degradation rate of phenol in the photoelectric combined catalytic process was 82.8%, showing an obvious synergistic effect. However, the device used cannot realize direct observation of the catalytic hydrogen evolution reaction (HER) under a microscope, and does not involve the problem of promoting the separation of photogenerated carriers of catalyst particles and improving the efficiency of photocatalytic reactions.

[0005] The inventor's previous patent CN111318274A disclosed a single-particle photocatalytic material, a single-molecule fluorescence detection method, and a detection device and application thereof, but did not address the issues of detecting the efficiency of the hydrogen evolution reaction of semiconductor photocatalysts, promoting the separation of photogenerated carriers of catalyst particles, and improving the efficiency of photocatalytic reactions. Summary of the invention

[0006] In view of the above, the present invention provides a method for enhancing the HER efficiency of semiconductor photocatalysts by electric field. Since the application of bias voltage will form an electric field perpendicular to the electrode plate and uniformly parallel, the separation of photogenerated carriers of catalyst particles is promoted under the action of Coulomb force, and the efficiency of photocatalytic reaction is improved, which has good practical application value.

[0007] The object of the present invention is to increase the efficiency of HER.

[0008] Another object of the present invention is to provide a method for enhancing the photocatalytic water dissociation efficiency of a semiconductor photocatalyst by applying an electric field (>0 V).

[0009] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0010] The first aspect of the present invention provides the use of an electric field in enhancing the efficiency of a semiconductor photocatalyst hydrogen evolution reaction.

[0011] The present invention has found that the photocatalytic efficiency of a semiconductor can be increased by subjecting the semiconductor photocatalyst to an electric field. Therefore, one aspect of the present invention provides a method for increasing the photocatalytic activity of a semiconductor by subjecting the semiconductor photocatalyst to an electric field (>0V).

[0012] In a preferred embodiment of this aspect, the photocatalytic activity of the semiconductor photocatalyst can be enhanced by exposing it to an electric field having an electric field strength greater than 0V.

[0013] In some embodiments, the semiconductor photocatalyst is selected from at least one of BiVO4, ZnO, TiO2, MoS2, CuS, In2S3, and CuInS2.

[0014] In some embodiments, the electric field strength is >0.

[0015] In some embodiments, the electric field strength ranges from -0.5V to 2V.

[0016] In some embodiments, the reaction solution includes an oxidation reaction solution and a reduction reaction solution, more specifically, a photogenerated electron scavenger MV in an AR solution. 2+ And CH3OH, the photogenerated hole scavenger in Re solution.

[0017] In a preferred embodiment of the present invention, the semiconductor nanorod array photocatalyst is selected from BiVO4.

[0018] Another aspect of the present invention relates to the use of a semiconductor photocatalyst with electric field enhancement obtained by a method according to an embodiment of the present invention in photocatalytic HER.

[0019] The third aspect of the present invention provides the application of semiconductor nanorod arrays in the study of the efficiency detection of hydrogen evolution reaction on the surface of catalyst particles.

[0020] In some embodiments, a semiconductor nanorod array is placed in an electric field control device, which is then placed in a quartz reactor containing water, irradiated with ultraviolet light and applied with voltages of different electric field strengths to stimulate a hydrogen evolution reaction on the catalyst surface, and then single-molecule fluorescence images and single-molecule fluorescence signals are collected for research.

[0021] The fourth aspect of the present invention provides an electric field control device, comprising: two glass sheets and two double-sided tapes, the double-sided tapes are adhered between two transparent glass sheets, and the two double-sided tapes are arranged at intervals to form a microchannel; the two glass sheets are both ITO glass electrodes, serving as a working electrode and a counter electrode respectively.

[0022] A fifth aspect of the present invention provides a method for detecting the efficiency of a semiconductor photocatalyst hydrogen evolution reaction, comprising:

[0023] Dispersing a semiconductor photocatalyst on the microchannel substrate of the electric field control device, and fixing it overnight at 90-95° C. to obtain an electric field control device loaded with a semiconductor photocatalyst;

[0024] The electric field control device loaded with semiconductor photocatalyst is placed in a water-containing quartz reactor, immersed in water, irradiated with ultraviolet light and applied with voltages of different electric field strengths to stimulate hydrogen evolution reaction on the catalyst surface, and then single-molecule fluorescence images and single-molecule fluorescence signals are collected to obtain the obtained product.

[0025] In some embodiments, the ultraviolet light has a wavelength of 365 nm.

[0026] In some embodiments, the single-molecule fluorescence detection device includes the following components: a microfluidic chip, a catalytic light source, a total internal reflection fluorescence microscope optical path system, a dichroic mirror, a filter, an EMCCD and an imaging system; a reaction tank is arranged in the microfluidic chip, and the reaction tank is composed of two glass sheets and two double-sided tapes, the double-sided tapes are glued between two transparent glass sheets, and the two double-sided tapes are arranged at intervals to form a reaction tank; the catalytic light source and the total internal reflection fluorescence microscope optical path system are respectively used to provide a single wavelength of catalytic light and laser to the reaction tank; the dichroic mirror is used to collect the fluorescence signal excited in the reaction tank, and the dichroic mirror, the filter, the EMCCD and the imaging system are connected in sequence.

[0027] The beneficial effects of the present invention are:

[0028] (1) The present invention enhances the HER efficiency of semiconductor photocatalysts through electric fields. Since the application of bias voltage will form an electric field perpendicular to the electrode plates and uniformly parallel to them, the separation of photogenerated carriers of catalyst particles is promoted under the action of Coulomb force, which improves the efficiency of photocatalytic reaction and has good practical application value. Compared with the prior art, the present invention enriches the control methods for controlling the HER activity of semiconductor photocatalysts.

[0029] (2) The operation method of the present application is simple, universal, and easy to scale up for production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0031] Figure 1 is a construction flow chart of the electric field control device of the present invention;

[0032] Figure 2 This is a physical diagram of the electric field control device of the present invention;

[0033] Figure 3 The present invention uses BiVO4 as a photoelectrode to obtain the generation rate of H2 under an electric field and 365nm light radiation. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] The present invention is further explained by the following examples, but it does not constitute a limitation of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, the photochemical technology methods not described in detail in the examples are all conventional methods in the art, and the specific operations can be referred to the photochemical technology guide or product instructions.

[0037] As introduced in the background technology, the photocatalytic water splitting reaction process of semiconductor catalysts is limited by the low separation of photogenerated carriers, and its photocatalytic efficiency is still not ideal. Applying an external electric field in the photocatalytic process is a more flexible and controllable strategy, which has attracted more and more attention from researchers.

[0038] In view of this, the first aspect of the present invention is to construct a method for enhancing the HER efficiency of semiconductor photocatalysis by electric field, the method comprising:

[0039] --Construction of electric field control device: In order to realize the single-molecule level monitoring of the photocatalytic redox reaction on the BiVO4 surface, the present invention firstly constructs an electric field control device. It consists of a working electrode (WE, ITO glass electrode, 0.15mm thickness, 10Ωcm -2 ), Counter Electrode, CE, ITO glass electrode, 1.0 mm thickness, 10 Ω cm -2 ) and a microchannel (double-sided tape, 2.0 cm × 5.0 mm × 150 μm). The liquid channel is composed of a double-sided tape sandwiched between two ITO glass electrodes. The present invention deposits the BiVO4 sample on the microchannel substrate in a monodisperse state and fixes it at 90°C overnight.

[0040] ----Macroscopic fluorescence monitoring of photocatalytic redox activity under electric field: The prepared sample was placed in a quartz reactor containing 3.0 mL of deionized water. Subsequently, the photocatalytic HER activity of the BiVO4 nanorod array under electric field and 365 nm light irradiation was evaluated without adding any additives. Nitrogen was used as a carrier and deionized water as an oxygen source. The present invention used a GC-7920 micro gas chromatograph to measure the reaction products offline. The measurement results are shown in Figure 2. Figure 3 shown.

[0041] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to perform equivalent replacements on parts thereof. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention. Although the above describes the specific implementation modes of the present invention in conjunction with the accompanying drawings, it is not intended to limit the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative labor are still within the protection scope of the present invention.

Claims

1. Application of external electric field in enhancing the efficiency of hydrogen evolution reaction of semiconductor photocatalyst.

2. The use according to claim 1, characterized in that The semiconductor photocatalyst is selected from at least one of BiVO4, ZnO, TiO2, MoS2, CuS, In2S3, and CuInS2.

3. The use according to claim 1, characterized in that Electric field strength>0.

4. The use according to claim 1, characterized in that The electric field strength ranges from -0.5V to 2V.

5. Application of semiconductor nanorod arrays in the study of hydrogen evolution reaction efficiency detection on the surface of catalyst particles.

6. The use according to claim 5, characterized in that The semiconductor nanorod array is placed in an electric field control device, which is then placed in a quartz reactor containing water. It is irradiated with ultraviolet light and voltages of different electric field strengths are applied to stimulate the hydrogen evolution reaction on the catalyst surface. Single-molecule fluorescence images and single-molecule fluorescence signals are then collected for research.

7. An electric field control device, characterized in that: include: It consists of two glass sheets and double-sided tape, the double-sided tape is adhered between the two transparent glass sheets, and microchannels are etched on the double-sided tape; the two glass sheets are both ITO glass electrodes, serving as the working electrode and the counter electrode respectively, and the ITO glass electrodes can be provided with inlet / outlet holes to be connected to the inlet / outlet pipes.

8. A method for detecting the efficiency of a semiconductor photocatalyst hydrogen evolution reaction, characterized in that: include: Dispersing the semiconductor photocatalyst on the microchannel substrate of the electric field control device according to claim 7, and fixing it at 90-95° C. overnight to obtain an electric field control device loaded with the semiconductor photocatalyst; The electric field control device loaded with semiconductor photocatalyst is placed in a water-containing quartz reactor, immersed in water, irradiated with ultraviolet light and applied with voltages of different electric field strengths to stimulate hydrogen evolution reaction on the catalyst surface, and then single-molecule fluorescence images and single-molecule fluorescence signals are collected to obtain the obtained product.

9. The method for detecting the efficiency of the semiconductor photocatalyst hydrogen evolution reaction according to claim 8, characterized in that: The wavelength of ultraviolet light is 365nm.

10. The method for detecting the efficiency of the semiconductor photocatalyst hydrogen evolution reaction according to claim 8, characterized in that: The single-molecule fluorescence detection device comprises the following components: a microfluidic chip, a catalytic light source, a total internal reflection fluorescence microscope optical path system, a dichroic mirror, a filter, an EMCCD and an imaging system; a reaction tank is arranged in the microfluidic chip, and the reaction tank is composed of two glass sheets and two double-sided adhesive tapes, wherein the double-sided adhesive tapes are adhered between two transparent glass sheets, and the two double-sided adhesive tapes are arranged at intervals, thereby forming the reaction tank; the catalytic light source and the total internal reflection fluorescence microscope optical path system are respectively used to provide catalytic light and laser of a single wavelength to the reaction tank; the dichroic mirror is used to collect the fluorescence signal excited in the reaction tank, and the dichroic mirror, the filter, the EMCCD and the imaging system are connected in sequence.

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