In-situ electrochemical absorption spectroscopy measurement system and method with microsecond time resolution

Abstract

The application discloses an in-situ electrochemical absorption spectrum measuring system and method with microsecond time resolution. The measuring system comprises an electrochemical workstation, a circuit control unit, a computer, an electrochemical reaction device and an ultraviolet-visible absorption spectrum device. The electrochemical workstation is electrically connected with the circuit control unit, the computer and the electrochemical reaction device respectively. The ultraviolet-visible absorption spectrum device is electrically connected with the circuit control unit and the computer respectively. The electrochemical reaction device comprises a working electrode, and the working electrode is electrically connected with the circuit control unit. The ultraviolet-visible absorption spectrum device comprises a probe light source, a detection unit and a signal acquisition unit. The system can perform in-situ ultraviolet-visible absorption spectrum test with microsecond time resolution, which provides a new way for obtaining electrochemical reaction kinetics information occurring on a microsecond time scale.

Description

Technical Field

[0001] This application relates to an in-situ electrochemical absorption spectroscopy measurement system and method with microsecond time resolution, belonging to the field of electrochemical detection technology. Background Technology

[0002] Clean energy, environmental protection, energy conversion, and storage have practical application value. Electrocatalysis has received widespread attention in energy conversion and storage. Many important electrocatalytic processes occur on a microsecond timescale, such as the ultrafast / fast processes of intermediate species generated by electrocatalysts in catalytic reactions, and the ultrafast / fast kinetic processes of intermediate species transformation and participation in the reaction. These processes mainly occur on a microsecond-millisecond timescale, and understanding these kinetic processes is crucial, requiring monitoring using spectroscopic methods with microsecond time resolution. However, due to technological limitations, research is very limited. In-situ UV-Vis absorption spectroscopy can monitor the valence state and concentration changes of reaction intermediate species in real time, becoming a powerful tool for studying electrocatalytic reaction processes. However, the time resolution of current in-situ UV-Vis absorption spectroscopy is mostly on the order of seconds. Kinetic processes occurring on shorter timescales (such as the microsecond order) cannot be monitored. Therefore, there is an urgent need for an in-situ UV-Vis absorption spectroscopy method with microsecond time resolution to solve the technical problem of monitoring intermediate species on a microsecond timescale in electrocatalysis. Summary of the Invention

[0003] The purpose of this invention is to provide an in-situ electrochemical absorption spectroscopy measurement system and method with microsecond time resolution. It utilizes an electrochemical workstation to provide operating conditions, a circuit control unit to provide a trigger signal for spectral acquisition, and a pulse control signal to control the bias pulse width of the constant potential and the on / off state of the circuit. Simultaneously, under the condition of constant potential applied to the sample, ultraviolet-visible absorption spectroscopy is used to test the kinetic information of intermediate species generated in the electrocatalytic reaction.

[0004] To achieve the above objectives, this application provides an in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution. This system enables in-situ ultraviolet-visible absorption spectroscopy measurements on a microsecond timescale.

[0005] One aspect of this application provides an in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution, comprising: an electrochemical workstation, a circuit control unit, a computer, an electrochemical reaction device, and an ultraviolet-visible absorption spectroscopy device;

[0006] The electrochemical workstation is electrically connected to the circuit control unit, the computer, and the electrochemical reaction device, respectively; the ultraviolet-visible absorption spectroscopy device is electrically connected to the circuit control unit and the computer, respectively.

[0007] The electrochemical reaction device includes a working electrode, which is electrically connected to the circuit control unit;

[0008] The ultraviolet-visible absorption spectroscopy device includes a detection light source, a detection unit, and a signal acquisition unit. The detection unit is used to convert the detection light passing through the working electrode into an electrical signal, and the signal acquisition unit is used to acquire the electrical signal output from the detection unit.

[0009] The computer is connected to the electrochemical workstation and the ultraviolet-visible absorption spectrometer respectively, and is used to control the operation of the electrochemical workstation and the ultraviolet-visible absorption spectrometer.

[0010] The ultraviolet-visible absorption spectroscopy device includes a detection light source, a detection unit, and a signal acquisition unit. Under in-situ testing conditions, the detection light needs to pass through a working electrode coated with the sample to be tested. The detection unit is used to convert the detection light transmitted from the test sample into an electrical signal. The signal acquisition unit is used to acquire the electrical signal output from the detector.

[0011] Optionally, the electrochemical reaction device further includes a reference electrode and a counter electrode;

[0012] The electrochemical workstation is electrically connected to the reference electrode and the counter electrode, respectively.

[0013] The electrochemical workstation is connected to a three-electrode electrochemical system, which includes a reference electrode (RE), a counter electrode (CE), and a working electrode (WE). All electrodes are placed in an electrochemical reaction cell containing an electrolyte solution; the test electrode is coated with a test sample.

[0014] Optionally, the circuit control unit is electrically connected to the signal acquisition unit. The circuit control unit outputs a pulse control signal to control the width of the constant potential bias pulse and the on / off state of the circuit, and simultaneously triggers the acquisition of ultraviolet-visible absorption spectrum signals by outputting a trigger signal.

[0015] Optionally, the signal acquisition unit includes an oscilloscope module.

[0016] Another aspect of this application provides a method for measuring in-situ electrochemical absorption spectroscopy with microsecond time resolution, which can simultaneously perform electrochemical and ultraviolet-visible absorption spectroscopy tests.

[0017] Optionally, the measurement method includes: using the above-mentioned in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution, outputting pulse control signals and trigger signals through the circuit control unit to control the on / off state of the circuit, and performing in-situ testing on the sample to be tested;

[0018] The in-situ test is a test that combines electrochemical testing and UV-Vis absorption spectroscopy testing simultaneously.

[0019] The test sample is coated on the working electrode.

[0020] Under in-situ testing conditions, the probe light needs to pass through the working electrode coated with the test sample, and the detection unit is used to convert the probe light into an electrical signal.

[0021] Optionally, the measurement method specifically includes the following steps:

[0022] (1) Start the electrochemical workstation and ultraviolet-visible absorption spectroscopy device via computer;

[0023] (2) The electrochemical workstation is selected in constant potential measurement mode and outputs constant potential;

[0024] (3) The circuit control unit outputs a pulse control signal to control the on / off state of the circuit and the width of the bias pulse of the constant potential; the circuit control unit outputs a trigger signal to trigger the signal acquisition unit;

[0025] (4) The test results output by the electrochemical workstation and the signal acquisition unit are processed by the computer.

[0026] Optionally, the bias pulse width is ≥1μs.

[0027] Optionally, the time resolution of the test results can be up to 1 microsecond.

[0028] As one specific implementation method, the measurement method specifically includes the following steps:

[0029] Step 1: After connecting the circuit, turn on the electrochemical workstation and the UV-Vis absorption spectroscopy device.

[0030] Step 2: Start the electrochemical workstation program via computer, initialize the electrochemical workstation, and then start the UV-Vis absorption spectroscopy device control program to set the parameters required for absorption spectrum testing.

[0031] Step 3: Select the constant potential measurement mode of the electrochemical workstation. Combine this with the pulse control signal output by the circuit control unit to control the bias pulse width of the constant potential and the on / off state of the circuit. While performing electrochemical testing on the test sample, the acquisition of UV-Vis absorption spectroscopy signals is triggered by the trigger signal output by the circuit control unit. In the following embodiment, the electrochemical workstation outputs a constant potential, such as 1.60V. At this time, the control signal of the circuit control unit is activated to control the bias pulse width (microseconds to seconds) of the constant potential actually applied to the working electrode and the on / off state of the circuit. For example, the control circuit is turned on for a period of time (4s, 128ms, 16ms respectively) and then turned off for a period of time (6s, 9.827s, 9.984s respectively), for a total of 10s as one cycle, and the output is cyclical. While performing electrochemical testing on the test sample, the in-situ UV-Vis absorption spectrum of the test sample is measured using a UV-Vis absorption spectroscopy device with a microsecond time resolution.

[0032] Step 4: Feed the results of the electrochemical test and the UV-Vis absorption spectroscopy test back to the computer for processing.

[0033] The beneficial effects that this application can produce include:

[0034] The technical solution of this application enables the use of an electrochemical workstation to provide working conditions for samples during UV-Vis absorption spectroscopy testing. This allows for the detection and analysis of species valence states and concentration changes in the samples using UV-Vis absorption spectroscopy. By combining the constant potential testing mode output by the electrochemical workstation with the control signal output by the circuit control unit, the kinetic changes of intermediate species in the test sample under in-situ conditions on a microsecond timescale can be obtained, providing a new approach for investigating the reaction mechanisms of catalysts under working conditions. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of an in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution provided in Embodiment 1 of this application.

[0036] Figure 2 This is a schematic diagram of a measurement method for simultaneously performing electrochemical and ultraviolet-visible absorption spectroscopy measurements, as provided in Example 2 of this application.

[0037] Figure 3 This is the test result of simultaneous electrochemical testing and UV-Vis absorption spectroscopy testing in Example 2 of this application, where Figure a shows the results using... Figure 2 Figure 1 shows the in-situ spectral test results obtained using the testing method described above; Figure 2 shows the corresponding current-time plot; Figure 3 shows the results obtained using the method described above. Figure 2 The test method obtains the in-situ spectral test pattern by controlling the width of the constant potential pulse by changing the width of the bias pulse of the control signal.

[0038] Figure 4 The following is a 16-millisecond test data graph for Embodiment 2 of this application, wherein graph a is an in-situ spectral test data graph with microsecond time resolution obtained under in-situ conditions with a bias pulse width of 16 milliseconds; graph b is a magnified spectral graph from 1 microsecond to 10 microseconds in graph a.

[0039] Figure 5 This is a diagram of the control signal with a bias pulse width of 1 microsecond output by the circuit control unit in this invention. Detailed Implementation

[0040] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the specific embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0041] Example 1

[0042] Figure 1 A schematic diagram of the microsecond time-resolved in-situ electrochemical absorption spectroscopy measurement system provided by the present invention is shown below. Figure 1 As shown, this embodiment discloses an in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution, which includes: a computer, an electrochemical workstation, a circuit control unit, an ultraviolet-visible absorption spectroscopy device, and an electrochemical reaction device; wherein the ultraviolet-visible absorption spectroscopy device includes a detection light source, a detection unit, and a signal acquisition unit; the electrochemical reaction device is a three-electrode electrochemical system, which includes a reference electrode (RE), a counter electrode (CE), and a working electrode (WE).

[0043] A computer is connected to both the electrochemical workstation and the UV-Vis absorption spectroscopy device to control their operation. The electrochemical workstation is connected to a three-electrode electrochemical system, with each electrode placed in an electrochemical reaction cell containing an electrolyte solution. A test sample is coated onto the working electrode. The working electrode of the electrochemical workstation, the working electrode coated with the test sample in the electrolytic cell, and the circuit control unit are connected. The counter electrode of the electrochemical workstation is connected to the counter electrode in the electrolytic cell, and the reference electrode of the electrochemical workstation is connected to the reference electrode in the electrolytic cell. Figure 1 As shown.

[0044] The circuit control unit is connected to the working electrode coated with the test sample in the electrolytic cell, and outputs a pulse control signal to control the width of the constant potential bias pulse and the on / off state of the circuit. The circuit control unit is also connected to the signal acquisition unit, and is used to output a trigger signal to trigger the acquisition of ultraviolet-visible absorption spectral signals.

[0045] In the in-situ testing conditions of the ultraviolet-visible absorption spectroscopy device, the detection light source needs to pass through a working electrode coated with a test sample. The detection unit is used to convert the detection light transmitted from the test sample into an electrical signal. The signal acquisition unit is used to acquire the electrical signal output from the detector, wherein the oscilloscope module in the signal acquisition unit can acquire electrical signals on the microsecond to second timescale.

[0046] In microsecond-time-resolved in-situ UV-Vis absorption spectroscopy, the bias pulse width of the control signal can be varied from microseconds to seconds by the circuit control unit, thereby controlling the width of the constant potential bias pulse output by the electrochemical workstation from microseconds to seconds. Because the bias pulse width of the constant potential has a large range of variability (from microseconds to seconds) in this in-situ test, the kinetic changes of intermediate species can be studied on a microsecond timescale by acquiring microsecond-time-resolved in-situ UV-Vis absorption spectra.

[0047] Example 2

[0048] Figure 2 This is a schematic diagram of a measurement method for in-situ ultraviolet-visible absorption spectroscopy with microsecond time resolution provided in Embodiment 1 of the present invention. The method includes the following steps:

[0049] Step 1: After connecting the circuit, turn on the electrochemical workstation and the UV-Vis absorption spectrometer, and set the test parameters in the UV-Vis absorption spectrometer.

[0050] Step Two: Select the constant potential measurement mode of the electrochemical workstation. Combine this with the pulse control signal output by the circuit control unit to control the bias pulse width of the constant potential and the on / off state of the circuit. While performing electrochemical testing on the sample, the acquisition of the UV-Vis absorption spectrum signal is triggered by the trigger signal output by the circuit control unit. In this embodiment, the electrochemical workstation outputs a constant potential of 1.60V. At this time, the control signal of the circuit control unit is activated to control the bias pulse width (microseconds to seconds) of the constant potential actually applied to the working electrode and the on / off state of the circuit. For example, the control circuit is turned on for a period of time (4s, 128ms, 16ms respectively) and then turned off for a period of time (6s, 9.827s, 9.984s respectively), for a total of 10s as one cycle, and this cycle is repeated. While performing electrochemical testing on the sample, the UV-Vis absorption spectrum of the sample is measured in situ with a microsecond time resolution using a UV-Vis absorption spectrometer. A non-situ UV-Vis absorption spectrum is also measured when no potential is applied to the sample to obtain the initial state UV-Vis absorption spectrum test results.

[0051] The results of the electrochemical test and the results of the ultraviolet-visible absorption spectrum test are output to the computer for processing.

[0052] After the test results are processed, as follows Figure 3 As shown in the figure, Figures a and b are the UV-Vis absorption spectra and corresponding current-time plots when the pulse bias width is 4 s, respectively. Figure c is the spectral test plot as the pulse bias width changes. It can be seen that the accumulation of high-valence species concentration increases with the increase of the bias pulse width. When the pulse bias signal is interrupted, the species concentration begins to decrease rapidly, indicating that the intermediate species accumulated under the biased state are rapidly consumed in the reaction after the bias is cut off. After a large amount of intermediate species are consumed, there is a relatively slow decay that can be attributed to the slow relaxation process of intermediate species.

[0053] Figure 4 In the figure, Figure a shows the test spectrum results from microseconds to seconds when the pulse bias width is 16ms; Figure b is a magnified view of Figure a from 1 microsecond to 10 microseconds, which shows that the time resolution of the spectrum test is on the order of 1 microsecond.

[0054] Figure 5 It is a control signal with a 1-microsecond pulse bias width output by the circuit control signal.

[0055] The above results demonstrate that the measurement system of the present invention can achieve microsecond time resolution measurement, obtain the correlation between the valence state change and species concentration change of intermediate species and the pulse bias width; at the same time, these results fully illustrate the sensitivity of the in-situ ultraviolet-visible absorption spectrometer with microsecond time resolution to the valence state and concentration of catalysts, and can reflect the dynamic change process of species concentration in a wide time range in real time, revealing clear reaction kinetic information.

[0056] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. An in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution, Its features are, Includes: electrochemical workstation, circuit control unit, computer, electrochemical reaction device, and ultraviolet-visible absorption spectroscopy device; The electrochemical workstation is electrically connected to the circuit control unit, the computer, and the electrochemical reaction device, respectively; the ultraviolet-visible absorption spectroscopy device is electrically connected to the circuit control unit and the computer, respectively. The electrochemical reaction device includes a working electrode, which is electrically connected to the circuit control unit; The ultraviolet-visible absorption spectroscopy device includes a detection light source, a detection unit, and a signal acquisition unit. The detection unit is used to convert the detection light source passing through the working electrode into an electrical signal, and the signal acquisition unit is used to acquire the electrical signal output from the detection unit. The circuit control unit is electrically connected to the signal acquisition unit; The circuit control unit outputs a trigger signal to trigger the signal acquisition unit; The circuit control unit controls the width of the constant potential output by the electrochemical workstation from microseconds to seconds by changing the width of the bias pulse of the control signal from microseconds to seconds.

2. The in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution according to claim 1, characterized in that, The electrochemical reaction device also includes a reference electrode and a counter electrode; The electrochemical workstation is electrically connected to the reference electrode and the counter electrode, respectively.

3. The in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution according to claim 1, characterized in that, The signal acquisition unit includes an oscilloscope module.

4. A method for in-situ electrochemical absorption spectroscopy with microsecond time resolution. Its features are, Includes: using the in-situ electrochemical absorption spectroscopy measurement system with microsecond time resolution as described in any one of claims 1 to 3, controlling the on / off state of the circuit by outputting pulse control signals and trigger signals through the circuit control unit, and performing in-situ testing on the sample to be tested; The in-situ test is a test that combines electrochemical testing and UV-Vis absorption spectroscopy testing simultaneously. The test sample is coated onto the working electrode.

5. The measurement method according to claim 4, characterized in that, The measurement method includes the following steps: (1) Start the electrochemical workstation and ultraviolet-visible absorption spectroscopy device via computer; (2) The electrochemical workstation selects the constant potential measurement mode and outputs a constant potential; (3) The circuit control unit outputs a pulse control signal to control the on / off state of the circuit and the width of the bias pulse of the constant potential; the circuit control unit outputs a trigger signal to trigger the signal acquisition unit; (4) The test results output by the electrochemical workstation and the signal acquisition unit are processed by the computer.

6. The measurement method according to claim 5, characterized in that, The bias pulse width is ≥1 μs.

7. The measurement method according to claim 5, characterized in that, The time resolution of the test results can reach the level of 1 microsecond.

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