A device and method for measuring hole concentration on the surface of a photoelectrode.

Abstract

This invention discloses a device and method for measuring the hole concentration on the surface of a photoelectrode, comprising an electrolytic cell, a first light source, a second light source, optical elements, a silicon diode detector, a data acquisition device, an electrochemical workstation, and a computer. This invention achieves in-situ detection of the concentration of photogenerated holes on the electrode surface and its quantitative relationship with photocurrent by periodically irradiating the photoelectrode within the electrolytic cell with two beams of light of different periods and wavelengths. This invention can be applied to study the kinetics of electrode interface reactions in photoelectrochemical systems, providing more scientific guidance for the preparation of photoelectrodes.

Description

Technical Field

[0001] This invention application relates to the field of photoelectrochemical technology, specifically to a device and method for measuring the hole concentration on the surface of a photoelectrode. Background Technology

[0002] The direct conversion of solar energy into hydrogen energy through photoelectrochemical reactions has attracted widespread research worldwide. Improving hydrogen production efficiency and reducing its cost are key to realizing the industrial application of solar-powered hydrogen production, and represent current research hotspots and challenges. In recent years, photoelectrochemical water splitting, as an important method of solar-powered hydrogen production, has attracted extensive research from scholars around the world. However, despite decades of unremitting efforts, the current efficiency of hydrogen production through photoelectrochemical water splitting remains low, failing to meet the practical application requirements of solar-powered hydrogen production.

[0003] The anodic process of photoelectrochemical water splitting is an oxygen evolution reaction involving four holes and four protons. The slow kinetics of this reaction are a major limiting factor for low photoelectrochemical hydrogen production efficiency. For example, on the BiVO4 surface, the time constant for photogenerated holes participating in the electrochemical reaction is typically on the order of ms–s, while the time constant for photogenerated hole recombination is on the order of ps–ns. This severe mismatch in time constants is a significant reason for the poor photoelectrochemical performance of BiVO4. In the photoelectrochemical oxygen evolution process, in-situ measurement of the relationship between photogenerated hole concentration and photocurrent on the electrode surface is beneficial for revealing the influence of electrode potential on both photogenerated hole concentration and photocurrent, thus providing more scientific guidance for the fabrication of photoelectrodes. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, this invention provides a device and method for measuring the hole concentration on the surface of a photoelectrode. The principle involves using short-wavelength blue light to excite the photoelectrode to generate photogenerated holes and photocurrent. Simultaneously, the photogenerated hole concentration on the electrode surface is obtained by detecting the change in red light intensity caused by the absorption of photogenerated holes. This establishes the relationship between the photogenerated hole concentration and photocurrent on the electrode surface, revealing the influence of electrode potential on the photogenerated hole concentration and photocurrent, and scientifically guiding the design and fabrication of photoelectrodes.

[0005] The first aspect of this invention provides a device for measuring the hole concentration on the surface of a photoelectrode, comprising: The device comprises an electrolytic cell, a first light source, a second light source, optical elements, a silicon diode detector, a data acquisition device, an electrochemical workstation, and a computer. The electrolytic cell includes a base, a reaction chamber, a quartz glass cap, a working electrode, a reference electrode, and a counter electrode. The optical elements include a first collimating lens, a second collimating lens, a beam splitter, and a bandpass filter. The first collimating lens and beam splitter are located between the electrolytic cell and the first light source, and the second collimating lens and beam splitter are located between the first silicon diode detector and the second light source. The working electrode, reference electrode, counter electrode, first light source, and second light source are respectively connected to the electrochemical workstation. The electrochemical workstation, the first silicon diode detector, and the second silicon diode detector are connected to the input terminal of the data acquisition device, and the output terminal of the data acquisition device is connected to the computer. Further, according to claim 1, the device for measuring hole concentration on the photoelectrode surface is characterized in that the first light source is a red LED, and the second light source is a blue LED, and they are vertically distributed.

[0006] Furthermore, the wavelength of the light generated by the red LED is 600nm-800nm ​​(the center wavelength can be selected as needed).

[0007] Furthermore, the wavelength of the light generated by the blue LED is 400nm-500nm (the center wavelength can be selected as needed).

[0008] Furthermore, the beam splitter is used for splitting and combining the beams of the red LED and the blue LED.

[0009] Furthermore, the first light source is always on, while the second light source is turned on periodically.

[0010] Furthermore, the silicon diode detector is used to measure the intensity of red and blue light, wherein the first silicon diode detector is used to detect the actual intensity of red and blue light, and the second silicon diode detector is used to measure the intensity of red light after passing through the photoelectrode.

[0011] Furthermore, the bandpass filter is a 600nm-800nm ​​(center wavelength selected as needed) bandpass filter, located in front of the second silicon diode detector, to achieve the purpose of measuring only the intensity of red light.

[0012] A second aspect of this invention provides a method for measuring hole concentration on the surface of a photoelectrode, based on the aforementioned device for measuring hole concentration on the surface of a photoelectrode, comprising the following steps: S1. Assemble the electrolytic cell and inject the appropriate electrolyte into the reaction chamber of the electrolytic cell; S2, the working electrode, reference electrode, counter electrode, first light source and second light source are respectively connected to the electrochemical workstation, the electrochemical workstation, the first silicon diode detector and the second silicon diode detector are connected to the input terminal of the data acquisition device, and the output terminal of the data acquisition device is connected to the computer; S3. Turn on the computer, potentiostat, first light source and second light source, set the illumination period of different beams, set the sampling speed and total measurement time; S4. After the measurement is completed, turn off the instrument power and disassemble the electrolytic cell.

[0013] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of this application.

[0014] Beneficial technical effects of the present invention: This invention uses 660nm light generated by a red LED as the probe light for studying the concentration of photogenerated holes. After passing through a collimating lens and a beam splitter, the light passes through a photoelectrode and reaches a Si diode photodetector. The intensity of the 660nm light after passing through the photoelectrode can be detected by the Si diode. In addition, another beam of light generated by a blue LED illuminates the photoelectrode surface after passing through a collimating lens and a beam splitter, used to generate photogenerated holes and photocurrent. The intensity and switching period of 455nm light are controlled by software, and the resulting photocurrent, transmittance of 660nm light, and optical density difference (DOD) [DOD = log (I455nm off / I455nm on)] are measured simultaneously. By establishing a standard curve and quantitative relationship between the detected probe light density change and the surface hole concentration, the concentration of photogenerated holes on the electrode surface can be obtained by measuring the probe light density change generated by 455nm light of different intensities, and a quantitative relationship between photocurrent and surface hole concentration can be established. Attached Figure Description

[0015] Figure 1 This is a structural block diagram of a method and apparatus for measuring hole concentration on the surface of a photoelectrode according to the present invention. Among them, 100-electrolytic cell, 110-electrolytic cell base, 120-electrolytic cell reaction chamber, 130-quartz glass cover, 140-working electrode, 150-reference electrode, 160-counter electrode, 200-first light source, 300-first collimating lens, 400-beam splitter, 500-second light source, 600-second light source, 700-bandpass filter, 800-second silicon diode detector, 900-first silicon diode detector Figure 2 This is a graph showing the change in surface hole concentration of the BiVO4 electrode under different blue light intensities at a potential of 0.63 VRHE according to the present invention. Figure 3This is a graph showing the change in optical density of the BiVO4 electrode under different light intensities at a potential of 0.63 VRHE according to the present invention. Figure 4 This is the standard curve of the optical density of the potential BiVO4 electrode relative to the surface hole concentration at 0.63 VRHE according to the present invention; Figure 5 This is a graph showing the change in optical density of the CoOOH / Vo-BiVO4 electrode under different light intensities at a potential of 0.63 VRHE according to the present invention. Figure 6 This is a graph showing the change in surface hole concentration of the CoOOH / Vo-BiVO4 electrode under different light intensities at a potential of 0.63 VRHE according to the present invention. Figure 7 This is a graph showing the change in photocurrent density of the CoOOH / Vo-BiVO4 electrode under different light intensities at a potential of 0.63 VRHE according to the present invention. Detailed Implementation

[0016] The alternative embodiments of this application will now be described in more detail with reference to the accompanying drawings. While alternative embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0017] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0018] The following is a detailed description of the apparatus and method for measuring hole concentration on the surface of the photoelectrode according to the present invention, with reference to the accompanying drawings: Reference Figure 1A device for measuring hole concentration on the surface of a photoelectrode includes: an electrolytic cell, a first light source, a second light source, optical elements, a silicon diode detector, a data acquisition device, an electrochemical workstation, and a computer. The electrolytic cell 100 includes an electrolytic cell base 110, an electrolytic cell reaction chamber 120, a quartz glass cover 130, a working electrode 140, a reference electrode 150, and a counter electrode 160. The optical elements include a first collimating lens 300, a second collimating lens 600, a beam splitter 400, and a bandpass filter 700. The first collimating lens 300 and the beam splitter... Mirror 400 is located between electrolytic cell 100 and first light source 200. Second collimating mirror 600 and spectrometer 400 are located between first silicon diode detector 900 and second light source 500. Working electrode 140, reference electrode 150, counter electrode 160, first light source 200 and second light source 500 are respectively connected to electrochemical workstation. Electrochemical workstation, first silicon diode detector 900 and second silicon diode detector 800 are connected to input terminal of data acquisition device. Output terminal of data acquisition device is connected to computer.

[0019] In one embodiment of this invention application, the device for measuring hole concentration on the surface of a photoelectrode according to claim 1 is characterized in that the first light source is a red LED and the second light source is a blue LED, and they are vertically distributed.

[0020] In one embodiment of this invention, the wavelength of the light generated by the red LED is 600nm-800nm, preferably 660nm.

[0021] In one embodiment of this invention, the wavelength of the light generated by the blue LED is 400nm-500nm, preferably 455nm.

[0022] In one embodiment of this invention, the beam splitter is used for splitting and combining the beams of red LEDs and blue LEDs.

[0023] In one embodiment of this invention application, the first light source is always on, and the second light source is periodically turned on.

[0024] In one embodiment of this invention, the silicon diode detector is used to measure the light intensity of red and blue light, wherein the first silicon diode detector is used to detect the actual light intensity of red and blue light, and the second silicon diode detector is used to measure the light intensity of red light after passing through the photoelectrode.

[0025] In one embodiment of this invention, the bandpass filter is a 600nm-800nm ​​bandpass filter, located in front of the second silicon diode detector, to achieve the purpose of measuring only the intensity of red light.

[0026] A method for measuring hole concentration on the surface of a photoelectrode, based on the aforementioned device for measuring hole concentration on the surface of the photoelectrode, includes the following steps: S1. Assemble the electrolytic cell 100 and inject the corresponding electrolyte into the electrolytic cell reaction chamber 120; S2, the working electrode 140, the reference electrode 150, the counter electrode 160, the first light source 200, and the second light source 500 are respectively connected to the electrochemical workstation. The electrochemical workstation, the first silicon diode detector 900, and the second silicon diode detector 800 are connected to the input terminal of the data acquisition device. The output terminal of the data acquisition device is connected to the computer. S3. Turn on the computer, potentiostat, first light source 200 and second light source 500, set the illumination period of different beams, set the sampling speed and total measurement time; S4. After the measurement is completed, turn off the instrument power and disassemble the electrolytic cell.

[0027] The various embodiments of this invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A device for measuring hole concentration on the surface of a photoelectrode, characterized in that, The system includes an electrolytic cell, a first light source, a second light source, optical elements, a silicon diode detector, a data acquisition device, an electrochemical workstation, and a computer. The electrolytic cell (100) includes an electrolytic cell base (110), an electrolytic cell reaction chamber (120), a quartz glass cover (130), a working electrode (140), a reference electrode (150), and a counter electrode (160). The optical elements include a first collimating lens (300), a second collimating lens (600), a beam splitter (400), and a bandpass filter (700). The silicon diode detector includes a first silicon diode detector (900) and a second silicon diode detector (800). The first collimating lens... The collimating mirror (300) and the beam splitter (400) are located between the electrolytic cell (100) and the first light source (200). The second collimating mirror (600) and the beam splitter (400) are located between the first silicon diode detector (900) and the second light source (500). The working electrode (140), the reference electrode (150), the counter electrode (160), the first light source (200), and the second light source (500) are respectively connected to the electrochemical workstation. The electrochemical workstation, the first silicon diode detector (900), and the second silicon diode detector (800) are connected to the input terminal of the data acquisition device. The output terminal of the data acquisition device is connected to the computer. The first light source is a red LED, and the second light source is a blue LED, which are vertically distributed. The first light source is always on, and the second light source is turned on periodically. The silicon diode detector is used to measure the intensity of red and blue light, wherein the first silicon diode detector (900) is used to detect the actual intensity of red and blue light, and the second silicon diode detector (800) is used to measure the intensity of red light after passing through the photoelectrode. The bandpass filter (700) is a 600nm-800nm ​​bandpass filter, located in front of the second silicon diode detector (800), to achieve the purpose of measuring only the intensity of red light.

2. The device for measuring hole concentration on the surface of a photoelectrode according to claim 1, characterized in that, The wavelength of the light generated by the red LED is 600nm-800nm.

3. The device for measuring hole concentration on the surface of a photoelectrode according to claim 1, characterized in that, The wavelength of the light generated by the blue LED is 400nm-500nm.

4. The device for measuring hole concentration on the surface of a photoelectrode according to claim 1, characterized in that, The beam splitter (400) is used for splitting and combining the beams of the red LED and the blue LED.

5. A method for measuring the hole concentration on the surface of a photoelectrode, based on the measuring device for the hole concentration on the surface of a photoelectrode according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Assemble the electrolytic cell (100) and inject the corresponding electrolyte into the electrolytic cell reaction chamber (120); S2, the working electrode (140), the reference electrode (150), the counter electrode (160), the first light source (200), and the second light source (500) are respectively connected to the electrochemical workstation. The electrochemical workstation and the silicon diode detectors (800, 900) are connected to the input terminal of the data acquisition device. The output terminal of the data acquisition device is connected to the computer. S3. Turn on the computer, potentiostat, first light source (200) and second light source (500), set the illumination period of different beams, set the sampling speed and total measurement time; S4. After the measurement is completed, turn off the instrument power and disassemble the electrolytic cell.

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