Transient potential scanning circuit for optical and electro-catalytic reaction detection research

Abstract

The invention discloses a transient potential scanning circuit for optical and electro-catalytic reaction detection research, which comprises a numerical control capacitor charging circuit, a capacitor polarity conversion circuit, a capacitor discharging signal conditioning circuit, a program control gain I / V conversion circuit and a microcontroller, the upper computer outputs a capacitor charging voltage value setting instruction, a capacitor discharging polarity setting instruction and a gain setting instruction to the microcontroller at a time through a serial port communication protocol, and controls the microcontroller to accurately execute charging, discharging and gain control operations. A current signal of a working electrode of the electrochemical cell can be effectively amplified through the program control gain I / V conversion circuit; the method has the advantages that the setting accuracy of the charging voltage of the capacitor can be improved, the detection difficulty of the weak current signal of the working electrode of the electrochemical cell can be reduced, the detection operation process is simple and convenient, and misoperation is not easy to occur.

Description

Technical Field

[0001] The present invention relates to a transient potential scanning circuit, and more particularly to a transient potential scanning circuit for detecting and researching photo - electro - catalytic reactions. Background Art

[0002] In the development of modern society, catalytic reaction detection technology has become a key factor in promoting energy conversion and industrial development. As the cornerstone of the chemical industry, catalytic reactions are applied in many important fields such as petrochemical industry, environmental monitoring, and the energy field. Photo - electro - catalytic reaction technology, as an emerging green catalytic technology, shows great potential in energy conversion and environmental remediation. In the research of photo - electro - catalytic reactions, by continuously optimizing and improving the methods for detecting catalytic reactions, information on the changes in the electric double - layer interface of catalytic reactions can be obtained, providing important technical support for catalyst performance detection and the optimization of catalytic reaction conditions.

[0003] In the research of photo - electro - catalytic reaction mechanisms, traditional in - situ characterization techniques such as in - situ infrared, in - situ Raman, and in - situ synchrotron radiation are widely used due to their fast testing and time - series recording capabilities. These techniques can reveal the surface state of catalysts, reaction intermediates, changes in the structure of active sites, and the dynamic evolution of chemical bonds, thus enabling an in - depth understanding of the behavior of catalysts under working conditions. However, these techniques have limitations such as strict experimental conditions, high equipment costs, complex operations, and large space requirements for detection, which limit their wide application. Although microscope detection techniques have low experimental condition limitations and simple operations and can perform real - time detection, they also have the problem of high cost.

[0004] Electrochemical testing also has the possibility of studying catalytic reaction mechanisms under time - series conditions. By using information such as current and voltage in an electrochemical cell system, it can provide information on the charge separation and transfer rates during photo - electro - catalytic reactions, thereby revealing the behavior of catalysts under actual working conditions. However, existing electrochemical research methods such as polarization curves and cyclic voltammetry curves are prone to masking useful information at high scan rates, while the ac impedance method has a long testing time. Therefore, a transient potential scanning circuit with dynamic real - time detection characteristics is crucial for promoting the electrochemical detection of photo - electro - catalytic reactions.

[0005] The transient detection technique for studying the dynamic charge distribution on the catalyst surface was reported in Document 1 “K. Qin, H. Yu, W. Zhu, Y. Zhou, Z. Guo, Q. Shao, Y. Wu, X. Wang, Y. Li, Y. Ji, F. Liao, Y. Liu, Z. Kang, M. Shao, 1D Monoclinic IrxRu1-xO2 Solid Solution with Ru-Enhanced Electrocatalytic Activity for Acidic Oxygen Evolution Reaction. Adv. Funct. Mater. 2024, 2402226.” It studies the charge response of the catalyst at different potentials to reveal the behavior of active sites in the electrochemical reaction. This transient detection technique first charges a fixed capacitor to a certain potential (U0), and then quickly connects the charged capacitor to the electrochemical system to simulate the response of the electrocatalyst at this potential. Its transient potential sweep (TPS) circuit is as shown in Figure 1 shown. The current change in this transient potential sweep circuit reflects the dynamic process of the charge distribution on the catalyst surface and the redox reaction. In an RC circuit, the relationship between the current (i), resistance (R), capacitance (C), and applied voltage (U) can be described by the following formula: where τ = RC is the time constant of the circuit, and e is the base of the natural logarithm. By measuring and analyzing the change of current with time at different potentials, the researchers can obtain the current of the catalyst at different voltages to analyze the surface state of the catalyst at different voltages. Thus, with the increase of the applied voltage U0 in the above transient detection technique, the peak current also increases. The charge quantity (Q) obtained by integrating the current within a short time (0.01 milliseconds) can be used to obtain the influencing factors of the active sites of the catalyst by comparing the charge quantities of different catalysts.

[0006] Reference 2 “Jiaxuan W, Jiacheng L, Zenan L, et al. In-situ study of the hydrogen peroxide photoproduction in seawater on carbon dot-based metal-free catalyst under operation condition[J]. Nano Research, 2024, 17(7): 5956-5964.” also mentions the transient test technology, which is used to analyze and study the mechanism of photocatalytic production of H2O2 in water and seawater. In principle, its transient potential scanning circuit can be simply described as a capacitor with adjustable positive or negative voltage, discharging to the working electrode (WE). The schematic diagram of the TPS test of its transient potential scanning circuit under dark conditions is shown in Fig. 2(a), and the corresponding equivalent circuit is shown in Fig. 2(b). The schematic diagram of the TPS test under illumination conditions is shown in Fig. 2(c), and the corresponding equivalent circuit is shown in Fig. 2(d). The schematic diagram of the TPS test under illumination conditions of -0.5v is shown in Fig. 2(e), and the corresponding equivalent circuit is shown in Fig. 2(f). In Fig. 2(b), Fig. 2(d) and Fig. 2(f), C0, C1, C2, C3 and C4 are the test capacitor 470 μF, the capacitance of the catalyst space charge region, the capacitance of the catalyst surface state and its pseudocapacitance, the interfacial double layer capacitance and the solid interface capacitance of the modified electrode respectively. R1 comes from the solution resistance, and R2 is the Faraday resistance corresponding to the reaction. As shown in Fig. 2(a) and Fig. 2(b), when there is no light on the transient potential scanning circuit, C0 will discharge. As shown in Fig. 2(c) and Fig. 2(d)), during the photocatalytic process, when the transient potential scanning circuit is illuminated, C0 and C1 discharge. As Figure 2(e) and 2(f) shown, C0 and C1 discharge together after illumination. For n-type semiconductors, when a negative voltage is applied, the directions of C0 and C1 are the same, and when a positive voltage is applied, the directions of C0 and C1 are opposite. After the capacitor discharges, the charging current decays exponentially until the charge in the transient potential scanning circuit reaches equilibrium. The relationship between the charge consumption time (τ) and the capacitance and resistance (τ = RC) is that as the reaction proceeds, there will be adsorption on the electrode surface, the medium increases, the capacitance will increase, and the decay time will also become longer. The curve of the current decay represents the generation or consumption of charge at the charge catalyst interface.

[0007] The working principles of the transient potential scanning circuits mentioned in the above two documents for studying photocatalytic and electrocatalytic reactions can both be understood as charging a capacitor and discharging the capacitor onto an electrochemical cell. By changing the charging voltage of the capacitor or the illumination condition of the electrochemical cell, the voltage and current conditions at both ends of the electrode are analyzed, so as to monitor the dynamic charge distribution in the photocatalytic and electrocatalytic reaction processes in real time. However, in the transient potential scanning circuits for photocatalytic and electrocatalytic reaction detection research in the above two documents, the magnitudes of the positive and negative voltages of the capacitor applied to the electrochemical cell are controlled by adjusting the knob of a digital potentiometer. The voltage adjustment is not precise enough, and there is a problem of large error in setting the charging voltage of the capacitor, resulting in low accuracy of the detection results. In an electrochemical cell, the electrochemical signals of the working electrode, such as current signals, are generally only a few milliamperes or a dozen milliamperes, and it is difficult to directly detect them. At the same time, the selection of forward and reverse charging of the capacitor in the transient potential scanning circuit is controlled by manually operating the buttons on the circuit board. It is necessary to switch the switch buttons back and forth. The detection operation process is complex, and problems such as accidental pressing of the buttons and contamination of the circuit panel by reagents are likely to occur during the detection operation process. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a transient potential scanning circuit for photocatalytic and electrocatalytic reaction detection research, which can improve the accuracy of setting the charging voltage of the capacitor, reduce the detection difficulty of the weak current signal of the working electrode of the electrochemical cell, has a simple detection operation process, and is not prone to misoperation.

[0009] The technical solution adopted by the present invention to solve the above technical problems is as follows: A transient potential scanning circuit for optoelectrochemical reaction detection research, including a numerically controlled capacitor charging circuit, a capacitor polarity conversion circuit, a capacitor discharge signal conditioning circuit, a programmable gain I / V conversion circuit, and a microcontroller. The capacitor polarity conversion circuit includes a first capacitor. The microcontroller can communicate with the host computer through the serial communication protocol, receive the capacitor charging voltage value setting instruction, the capacitor discharge polarity setting instruction, and the gain setting instruction set according to the detection operation requirements of the electrochemical cell at the host computer, and after receiving the capacitor charging voltage value setting instruction, the capacitor discharge polarity setting instruction, and the gain setting instruction, first output a corresponding voltage control signal to the numerically controlled capacitor charging circuit according to the capacitor charging voltage value setting instruction, so that the numerically controlled capacitor charging circuit outputs a voltage signal equal to the set value of the capacitor charging voltage to the capacitor polarity conversion circuit, and then output a polarity control signal according to the capacitor discharge polarity setting instruction to control the charging and the discharge polarity of the first capacitor, so that the voltage applied to the counter electrode of the electrochemical cell by the capacitor polarity conversion circuit is equal to the voltage value required by the actual experiment; The capacitor discharge signal conditioning circuit is used to follow the voltage applied to the counter electrode of the electrochemical cell by the capacitor polarity conversion circuit and generate a corresponding voltage signal for output; When the capacitor polarity conversion circuit applies voltage to the counter electrode of the electrochemical cell, the microprocessor outputs a corresponding gain control signal according to the gain setting instruction to control the programmable gain I / V conversion circuit to convert the current signal of the working electrode of the electrochemical cell into a voltage signal for output according to the set gain.

[0010] Compared with the prior art, the advantages of the present invention are that the capacitor charging voltage value setting instruction, the capacitor discharge polarity setting instruction, and the gain setting instruction are set at the host computer according to the detection operation requirements of the electrochemical cell, and the capacitor charging voltage value setting instruction, the capacitor discharge polarity setting instruction, and the gain setting instruction are output to the microcontroller at one time through the serial communication protocol, controlling the microcontroller to accurately execute the control operations of charging, discharging, and gain. There is no need to manually set and adjust the capacitor charging voltage, nor to manually operate the buttons multiple times, which greatly simplifies the test operation process, and there will be no accidental touch of the buttons during the detection operation process. At the same time, the current signal of the working electrode of the electrochemical cell can be effectively amplified by the programmable gain I / V conversion circuit, thereby expanding the detection range of the current signal of the working electrode of the electrochemical cell, facilitating subsequent acquisition and analysis. Therefore, the present invention can improve the accuracy of capacitor charging voltage setting, and can reduce the detection difficulty of the weak current signal of the working electrode of the electrochemical cell. The detection operation process is simple and it is not easy to have misoperations.

[0011] Further, the numerically controlled capacitor charging circuit has an input end and an output end, the capacitor polarity conversion circuit has an input end, an output end and two control ends, and its two control ends are respectively called the first control end and the second control end; the capacitor discharge signal conditioning circuit has an input end and an output end, the programmable gain I / V conversion circuit has an input end, an output end and two control ends, and its two control ends are respectively called the first control end and the second control end; the microcontroller has an input end and five output ends, and its five output ends are respectively called the first output end, the second output end, the third output end, the fourth output end and the fifth output end. The input end of the microcontroller is used to connect to the host computer through the serial communication protocol. The first output end of the microcontroller is used to output a voltage control signal. The second output end and the third output end of the microcontroller are used to output polarity control signals. The fourth output end and the fifth output end of the microcontroller are used to output gain control signals; the input end of the numerically controlled capacitor charging circuit is connected to the first output end of the microcontroller. The output end of the numerically controlled capacitor charging circuit is used to output a voltage signal whose magnitude is equal to the set value of the capacitor charging voltage. The output end of the numerically controlled capacitor charging circuit is connected to the input end of the capacitor polarity conversion circuit. The first control end of the capacitor polarity conversion circuit is connected to the second output end of the microcontroller. The second control end of the capacitor polarity conversion circuit is connected to the third output end of the microcontroller. The output end of the capacitor polarity conversion circuit is connected to the counter electrode of the electrochemical cell. The input end of the capacitor discharge signal conditioning circuit is connected to the counter electrode of the electrochemical cell. The input end of the programmable gain I / V conversion circuit is connected to the working electrode of the electrochemical cell. The first control end of the programmable gain I / V conversion circuit is connected to the fourth output end of the microcontroller. The second control end of the programmable gain I / V conversion circuit is connected to the fifth output end of the microcontroller.

[0012] Further, the numerically controlled capacitor charging circuit includes a first resistor, a second resistor, a third resistor, a first operational amplifier and a second operational amplifier. Both the first operational amplifier and the second operational amplifier have a non-inverting input end, an inverting input end and an output end. One end of the first resistor is connected to the inverting input end of the first operational amplifier. The non-inverting input end of the first operational amplifier is the input end of the numerically controlled capacitor charging circuit. The other end of the first resistor, the output end of the first operational amplifier and the non-inverting input end of the second operational amplifier are connected. The inverting input end of the second operational amplifier, one end of the second resistor and one end of the third resistor are connected. The other end of the third resistor is grounded. The other end of the second resistor is connected to the output end of the second operational amplifier, and its connection end is the output end of the numerically controlled capacitor charging circuit.

[0013] Furthermore, the capacitance polarity conversion circuit further includes a fourth resistor and two relays. Each relay has two normally open terminals, two normally closed terminals, two common terminals, and a control coil terminal. The two normally open terminals are respectively referred to as a first normally open terminal and a second normally open terminal, the two normally closed terminals are respectively referred to as a first normally closed terminal and a second normally closed terminal, and the two common terminals are respectively referred to as a first common terminal and a second common terminal. The control coil terminal of the relay is used to receive a control signal. When the control signal received by the control coil terminal of the relay is at a high level, its first normally open terminal conducts with the first common terminal, its second normally open terminal conducts with the second common terminal, its first normally closed terminal is cut off from the first common terminal, and its second normally closed terminal is cut off from the second common terminal; when the control signal received by the control coil terminal of the relay is at a low level, its first normally open terminal is cut off from the first common terminal, its second normally open terminal is cut off from the second common terminal, its first normally closed terminal conducts with the first common terminal, and its second normally closed terminal conducts with the second common terminal; the two relays are respectively referred to as a first relay and a second relay; one end of the fourth resistor is the input end of the capacitance polarity conversion circuit, the other end of the fourth resistor is connected to the first normally closed terminal of the first relay, the second normally closed terminal of the first relay is grounded, one end of the first capacitor is connected to the first common terminal of the first relay, the other end of the first capacitor is connected to the second common terminal of the first relay, the first normally open terminal of the first relay is connected to the first common terminal of the second relay, the second normally open terminal of the first relay is connected to the second common terminal of the second relay, the first normally closed terminal of the second relay is connected to its second normally open terminal, and the connection end is the output end of the capacitance polarity conversion circuit, the first normally open terminal and the second normally closed terminal of the second relay are both grounded, the control coil terminal of the first relay is the first control end of the capacitance polarity conversion circuit, and the control coil terminal of the second relay is the second control end of the capacitance polarity conversion circuit.

[0014] Furthermore, the capacitance discharge signal conditioning circuit includes a fifth resistor and a third operational amplifier. The third operational amplifier has a non-inverting input terminal, an inverting input terminal, and an output terminal. The non-inverting input terminal of the third operational amplifier is the input end of the capacitance discharge signal conditioning circuit, the inverting input terminal of the third operational amplifier is connected to one end of the fifth resistor, and the output terminal of the third operational amplifier is connected to the other end of the fifth resistor, and the connection end is the output end of the capacitance discharge signal conditioning circuit.

[0015] Further, the programmable gain I / V conversion circuit includes a fourth operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and a four-way analog switch; the four-way analog switch has four selection terminals, a common terminal, and two control terminals. The two control terminals of the four-way analog switch are respectively used to access selection signals. Under the control of the selection signals applied to the two control terminals, one of the four selection terminals of the four-way analog switch conducts with its common terminal, and the other three are cut off from its common terminal. The four selection terminals of the four-way analog switch are respectively referred to as its first selection terminal, second selection terminal, third selection terminal, and fourth selection terminal, and the two control terminals of the four-way analog switch are respectively referred to as its first control terminal and second control terminal; when the selection signals applied to the first control terminal and the second control terminal of the four-way analog switch are both low levels, its first selection terminal conducts with its common terminal, while the second selection terminal, third selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signal applied to the first control terminal of the four-way analog switch is a low level and the selection signal applied to the second control terminal is a high level, its second selection terminal conducts with its common terminal, while the first selection terminal, third selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signal applied to the first control terminal of the four-way analog switch is a high level and the selection signal applied to the second control terminal is a low level, its third selection terminal conducts with its common terminal, while the first selection terminal, second selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signals applied to the first control terminal and the second control terminal of the four-way analog switch are both high levels, its fourth selection terminal conducts with its common terminal, while the first selection terminal, second selection terminal, and third selection terminal are all cut off from its common terminal; the fourth operational amplifier has a non-inverting input terminal, an inverting input terminal, and an output terminal;The non-inverting input terminal of the fourth operational amplifier is grounded. The inverting input terminal of the fourth operational amplifier, one end of the sixth resistor, one end of the second capacitor, one end of the seventh resistor, one end of the third capacitor, one end of the eighth resistor, one end of the fourth capacitor, one end of the ninth resistor, and one end of the fifth capacitor are connected, and the connection terminal is the input terminal of the programmable gain I / V conversion circuit. The other end of the sixth resistor and the other end of the second capacitor are connected to the first selection terminal of the four-way analog switch. The other end of the seventh resistor and the other end of the third capacitor are connected to the second selection terminal of the four-way analog switch. The other end of the eighth resistor and the other end of the fourth capacitor are connected to the third selection terminal of the four-way analog switch. The other end of the ninth resistor, the other end of the fifth capacitor, and the fourth selection terminal of the four-way analog switch are connected. The common terminal of the four-way analog switch is connected to the output terminal of the fourth operational amplifier, and the connection terminal is the output terminal of the programmable gain I / V conversion circuit. The first control terminal of the four-way analog switch is the first control terminal of the programmable gain I / V conversion circuit; the second control terminal of the four-way analog switch is the second control terminal of the programmable gain I / V conversion circuit. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the transient potential scan (TPS) disclosed in Document 1;

[0017] Figure 2(a) is a schematic diagram of the principle of the TPS test of the transient potential scan circuit disclosed in Document 2 under dark conditions;

[0018] Figure 2(b) is an equivalent circuit diagram of Figure 2(a);

[0019] Figure 2(c) is a schematic diagram of the principle of the TPS test of the transient potential scan circuit disclosed in Document 2 under illumination conditions;

[0020] Figure 2(d) is an equivalent circuit diagram of Figure 2(c);

[0021] Figure 2(e) is a schematic diagram of the principle of the TPS test of the transient potential scan circuit disclosed in Document 2 under -0.5v illumination conditions;

[0022] Figure 2(f) is an equivalent circuit diagram of Figure 2(e);

[0023] Figure 3 It is a structural diagram of the transient potential scan circuit of the present invention for the detection and research of photo and electrocatalytic reactions;

[0024] Figure 4(a) is the circuit diagram of the numerical control capacitor charging circuit of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention;

[0025] Figure 4(b) is the circuit diagram of the capacitor polarity conversion circuit of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention;

[0026] Figure 4(c) is the circuit diagram of the capacitor discharge signal conditioning circuit of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention;

[0027] Figure 4(d) is the circuit diagram of the programmable gain I / V conversion circuit of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention;

[0028] Figure 5(a) shows that when a 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell, the microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is +1 V and the gain set according to the gain setting command is 10 K, the voltage signal V o1 output at the output terminal of the capacitor discharge signal conditioning circuit and the voltage signal V o2 output at the output terminal of the programmable gain I / V conversion circuit;

[0029] Figure 5(b) shows that when a 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell, the microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is +1 V and the gain set according to the gain setting command is 100 K, the voltage signal V o1 output at the output terminal of the capacitor discharge signal conditioning circuit and the voltage signal V o2 output at the output terminal of the programmable gain I / V conversion circuit;

[0030] Figure 5(c) shows that when a 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell, the microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is -1 V and the gain set according to the gain setting command is 10 K, the voltage signal V o1 output at the output terminal of the capacitor discharge signal conditioning circuit and the voltage signal V o2 output at the output terminal of the programmable gain I / V conversion circuit;

[0031] Figure 5(d) shows that when a 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell, the microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that when the voltage signal magnitude applied to the counter electrode of the electrochemical cell is -1 V and the gain set according to the gain setting command is 100 K, the voltage signal V o1 output at the output terminal of the capacitance discharge signal conditioning circuit and the voltage signal V o2 waveform diagram of the output at the output terminal of the programmable gain I / V conversion circuit;

[0032] Figure 6(a) shows that when a series circuit of a 10 kΩ resistor and a 0.47 μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell, the microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that when the voltage signal magnitude applied to the counter electrode of the electrochemical cell is +1 V and the gain set according to the gain setting command is 10 K, the voltage signal V o1 output at the output terminal of the capacitance discharge signal conditioning circuit and the voltage signal V o2 waveform diagram of the output at the output terminal of the programmable gain I / V conversion circuit;

[0033] Figure 6(b) shows that when a series circuit of a 10 kΩ resistor and a 0.47 μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell, the microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that when the voltage signal magnitude applied to the counter electrode of the electrochemical cell is +1 V and the gain set according to the gain setting command is 100 K, the voltage signal V o1 output at the output terminal of the capacitance discharge signal conditioning circuit and the voltage signal V o2 waveform diagram of the output at the output terminal of the programmable gain I / V conversion circuit;

[0034] Figure 6(c) shows that when a series circuit of a 10 kΩ resistor and a 0.47 μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell, the microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that when the voltage signal magnitude applied to the counter electrode of the electrochemical cell is -1 V and the gain set according to the gain setting command is 10 K, the voltage signal V o1 output at the output terminal of the capacitance discharge signal conditioning circuit and the voltage signal Vo2 Waveform diagram of;

[0035] Figure 6(d) shows a series circuit of a 10 kΩ resistor and a 0.47 μF capacitor connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for optoelectrocatalytic reaction detection research of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharge polarity setting command, so that when the voltage signal magnitude applied to the counter electrode of the electrochemical cell is -1 V and the gain set according to the gain setting command is 100 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 Waveform diagram of and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2 Waveform diagram of. Detailed implementation manner

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0037] Embodiment 1: As Figure 3 shown, a transient potential scanning circuit for optoelectrocatalytic reaction detection research includes a numerically controlled capacitor charging circuit, a capacitor polarity conversion circuit, a capacitor discharge signal conditioning circuit, a programmable gain I / V conversion circuit, and a microcontroller. The capacitor polarity conversion circuit includes a first capacitor C1. The microcontroller can communicate with the host computer through a serial communication protocol, receive the capacitor charging voltage value setting command, the capacitor discharge polarity setting command, and the gain setting command set according to the detection operation requirements of the electrochemical cell at the host computer, and after receiving the capacitor charging voltage value setting command, the capacitor discharge polarity setting command, and the gain setting command, first output a corresponding voltage control signal to the numerically controlled capacitor charging circuit according to the capacitor charging voltage value setting command, so that the numerically controlled capacitor charging circuit outputs a voltage signal equal to the set value of the capacitor charging voltage to the capacitor polarity conversion circuit, and then output a polarity control signal according to the capacitor discharge polarity setting command to control the charging and discharge polarity of the first capacitor C1, so that the voltage applied to the counter electrode of the electrochemical cell by the capacitor polarity conversion circuit is equal to the voltage magnitude required by the actual experiment; the capacitor discharge signal conditioning circuit is used to follow the voltage applied to the counter electrode of the electrochemical cell by the capacitor polarity conversion circuit and generate a corresponding voltage signal output; when the capacitor polarity conversion circuit applies a voltage to the counter electrode of the electrochemical cell, the microprocessor outputs a corresponding gain control signal according to the gain setting command to control the programmable gain I / V conversion circuit to convert the current signal of the working electrode of the electrochemical cell into a voltage signal output according to the set gain.

[0038] In this embodiment, the numerically controlled capacitor charging circuit has an input terminal and an output terminal. The capacitor polarity conversion circuit has an input terminal, an output terminal, and two control terminals, which are respectively referred to as the first control terminal and the second control terminal. The capacitor discharge signal conditioning circuit has an input terminal and an output terminal. The programmable gain I / V conversion circuit has an input terminal, an output terminal, and two control terminals, which are respectively referred to as the first control terminal and the second control terminal. The microcontroller has an input terminal and five output terminals, which are respectively referred to as the first output terminal, the second output terminal, the third output terminal, the fourth output terminal, and the fifth output terminal. The input terminal of the microcontroller is used to connect to the host computer through the serial communication protocol. The first output terminal of the microcontroller is used to output a voltage control signal. The second output terminal and the third output terminal of the microcontroller are used to output polarity control signals. The fourth output terminal and the fifth output terminal of the microcontroller are used to output gain control signals. The input terminal of the numerically controlled capacitor charging circuit is connected to the first output terminal of the microcontroller. The output terminal of the numerically controlled capacitor charging circuit is used to output a voltage signal whose magnitude is equal to the set value of the capacitor charging voltage. The output terminal of the numerically controlled capacitor charging circuit is connected to the input terminal of the capacitor polarity conversion circuit. The first control terminal of the capacitor polarity conversion circuit is connected to the second output terminal of the microcontroller. The second control terminal of the capacitor polarity conversion circuit is connected to the third output terminal of the microcontroller. The output terminal of the capacitor polarity conversion circuit is connected to the counter electrode of the electrochemical cell. The input terminal of the capacitor discharge signal conditioning circuit is connected to the counter electrode of the electrochemical cell. The input terminal of the programmable gain I / V conversion circuit is connected to the working electrode of the electrochemical cell. The first control terminal of the programmable gain I / V conversion circuit is connected to the fourth output terminal of the microcontroller. The second control terminal of the programmable gain I / V conversion circuit is connected to the fifth output terminal of the microcontroller.

[0039] In this embodiment, the capacitor discharge signal conditioning circuit follows the voltage applied to the counter electrode of the electrochemical cell by the capacitor polarity conversion circuit and generates a corresponding voltage signal for output through its output terminal. The programmable gain I / V conversion circuit converts the current signal of the working electrode of the electrochemical cell into a voltage signal for output under the control of the microcontroller. The voltage signal output by the capacitor discharge signal conditioning circuit and the voltage signal output by the programmable gain I / V conversion circuit are the transient potential sweep signals.

[0040] In this embodiment, according to the detection operation requirements of the electrochemical cell, the capacitor charging voltage value setting instruction, the capacitor discharging polarity setting instruction, and the gain setting instruction are set at the host computer, and the capacitor charging voltage value setting instruction, the capacitor discharging polarity setting instruction, and the gain setting instruction are output to the microcontroller at one time through the serial communication protocol, controlling the microcontroller to accurately execute the control operations of charging, discharging, and gain. There is no need to manually set and adjust the capacitor charging voltage, nor to manually operate the buttons multiple times, which greatly simplifies the test operation process. Moreover, there will be no accidental touch of the buttons during the detection operation. At the same time, the current signal of the working electrode of the electrochemical cell can be effectively amplified by the programmable gain I / V conversion circuit, thereby expanding the detection range of the current signal of the working electrode of the electrochemical cell, facilitating subsequent acquisition and analysis, and reducing the detection difficulty of the weak current signal of the working electrode of the electrochemical cell.

[0041] Embodiment 2: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, as shown in Fig. 4(a), the numerically controlled capacitor charging circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a first operational amplifier A1, and a second operational amplifier A2. Both the first operational amplifier A1 and the second operational amplifier A2 have a non-inverting input terminal, an inverting input terminal, and an output terminal. One end of the first resistor R1 is connected to the inverting input terminal of the first operational amplifier A1. The non-inverting input terminal of the first operational amplifier A1 is the input terminal of the numerically controlled capacitor charging circuit. The other end of the first resistor R1, the output terminal of the first operational amplifier A1, and the non-inverting input terminal of the second operational amplifier A2 are connected. The inverting input terminal of the second operational amplifier A2, one end of the second resistor R2, and one end of the third resistor R3 are connected. The other end of the third resistor R3 is grounded. The other end of the second resistor R2 is connected to the output terminal of the second operational amplifier A2, and the connection end is the output terminal of the numerically controlled capacitor charging circuit.

[0042] In the numerically controlled capacitor charging circuit of this embodiment, the first resistor R1 and the first operational amplifier A1 form a follower circuit. The first resistor R1 serves as a current-limiting resistor to protect the first operational amplifier A1 from being damaged by excessive input current. The second resistor R2, the third resistor R3, and the second operational amplifier A2 form a non-inverting amplifier circuit. The second resistor R2 and the third resistor R3 are used to set the amplification ratio of the second operational amplifier A2. When the microcontroller outputs the corresponding capacitor charging voltage to the input terminal of the numerically controlled capacitor charging circuit according to the capacitor charging voltage value setting instruction it receives, the first operational amplifier A1 automatically tracks the capacitor charging voltage, avoiding interference between digital and analog circuits, and outputs the corresponding voltage signal to the non-inverting output terminal of the second operational amplifier A2 through its output terminal. The second operational amplifier A2 amplifies the voltage signal and outputs the corresponding voltage signal through its output terminal.

[0043] Embodiment 3: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, as shown in Fig. 4(b), the capacitor polarity conversion circuit further includes a fourth resistor R4 and two relays. Each relay has two normally open terminals, two normally closed terminals, two common terminals, and a control coil terminal. The two normally open terminals are respectively referred to as the first normally open terminal and the second normally open terminal, the two normally closed terminals are respectively referred to as the first normally closed terminal and the second normally closed terminal, and the two common terminals are respectively referred to as the first common terminal and the second common terminal. The control coil terminal of the relay is used to connect to a control signal. When the control signal connected to the control coil terminal of the relay is at a high level, its first normally open terminal conducts with the first common terminal, its second normally open terminal conducts with the second common terminal, its first normally closed terminal is cut off from the first common terminal, and its second normally closed terminal is cut off from the second common terminal; when the control signal connected to the control coil terminal of the relay is at a low level, its first normally open terminal is cut off from the first common terminal, its second normally open terminal is cut off from the second common terminal, its first normally closed terminal conducts with the first common terminal, and its second normally closed terminal conducts with the second common terminal; the two relays are respectively referred to as the first relay U1 and the second relay U2; one end of the fourth resistor R4 is the input end of the capacitor polarity conversion circuit, the other end of the fourth resistor R4 is connected to the first normally closed terminal of the first relay U1, the second normally closed terminal of the first relay U1 is grounded, one end of the first capacitor C1 is connected to the first common terminal of the first relay U1, the other end of the first capacitor C1 is connected to the second common terminal of the first relay U1, the first normally open terminal of the first relay U1 is connected to the first common terminal of the second relay U2, the second normally open terminal of the first relay U1 is connected to the second common terminal of the second relay U2, the first normally closed terminal of the second relay U2 is connected to its second normally open terminal, and the connection end is the output end of the capacitor polarity conversion circuit. The first normally open terminal and the second normally closed terminal of the second relay U2 are both grounded. The control coil terminal of the first relay U1 is the first control end of the capacitor polarity conversion circuit, and the control coil terminal of the second relay U2 is the second control end of the capacitor polarity conversion circuit.

[0044] In the capacitor polarity conversion circuit of this embodiment, the fourth resistor R4 serves as a current-limiting resistor to limit the current flowing into the first relay U1 and prevent the first relay U1 from being damaged due to excessive current flowing into it.

[0045] When the second output terminal of the microprocessor outputs a low level, and the third output terminal outputs a high level or a low level, the first normally open terminal of the first relay U1 is cut off from the first common terminal of the first relay U1, and the second normally open terminal of the first relay U1 is cut off from the second common terminal of the first relay U1. The first normally closed terminal of the first relay U1 is conducted with the first common terminal of the first relay U1, and the second normally closed terminal of the first relay U1 is conducted with the second common terminal of the first relay U1. At this time, the first capacitor C1 and the fourth resistor R4 are connected to form a charging path, and the voltage signal input at the input terminal of the capacitor polarity conversion circuit charges the first capacitor C1 so that the first capacitor C1 is charged to the set capacitor charging voltage. Since the second output terminal of the microprocessor outputs a low level, both ends of the first capacitor C1 are cut off from the first normally open terminal, the second normally open terminal, the first normally closed terminal, the second normally closed terminal, the first common terminal, and the second common terminal of the second relay U2. The first capacitor C1 cannot form a discharge path with the counter electrode of the electrochemical cell, so the first capacitor C1 will not discharge to the counter electrode of the electrochemical cell.

[0046] When the second output terminal of the microprocessor outputs a high level and the third output terminal outputs a low level, the first normally open terminal of the first relay U1 is conducted with the first common terminal of the first relay U1, and the second normally open terminal of the first relay U1 is conducted with the second common terminal of the first relay U1. At this time, the first normally closed terminal of the first relay U1 is cut off from the first common terminal of the first relay U1, and the second normally closed terminal of the first relay U1 is cut off from the second common terminal of the first relay U1. The first normally open terminal of the second relay U2 is cut off from the first common terminal of the second relay U2, and the second normally open terminal of the second relay U2 is cut off from the second common terminal of the second relay U2. The first normally closed terminal of the second relay U2 is conducted with the first common terminal of the second relay U2, and the second normally closed terminal of the second relay U2 is conducted with the second common terminal of the second relay U2. At this time, the first capacitor C1 and the fourth resistor R4 cannot form a charging path, and the first capacitor C1 forms a discharge path with the counter electrode of the electrochemical cell. The first capacitor C1 discharges to the counter electrode of the electrochemical cell, and the voltage applied to the electrochemical counter electrode is a negative voltage.

[0047] When the second output terminal of the microprocessor outputs a high level and the third output terminal outputs a high level, the first normally open terminal of the first relay U1 is conducted with the first common terminal of the first relay U1, and the second normally open terminal of the first relay U1 is conducted with the second common terminal of the first relay U1. At this time, the first normally closed terminal of the first relay U1 is cut off from the first common terminal of the first relay U1, and the second normally closed terminal of the first relay U1 is cut off from the second common terminal of the first relay U1. The first normally open terminal of the second relay U2 is conducted with the first common terminal of the second relay U2, and the second normally open terminal of the second relay U2 is conducted with the second common terminal of the second relay U2. The first normally closed terminal of the second relay U2 is cut off from the first common terminal of the second relay U2, and the second normally closed terminal of the second relay U2 is cut off from the second common terminal of the second relay U2. At this time, the first capacitor C1 and the fourth resistor R4 cannot form a charging path, and the first capacitor C1 and the counter electrode of the electrochemical cell form a discharging path. The first capacitor C1 discharges to the counter electrode of the electrochemical cell, and the voltage applied to the counter electrode of the electrochemical cell is a positive voltage.

[0048] Thus, by the microprocessor setting the high and low levels output by its second output terminal and third output terminal according to the capacitor discharge polarity setting instruction, the charging of the first capacitor C1 and the discharge polarity of the first capacitor C1 can be controlled, so that the voltage magnitude applied by the first capacitor C1 to the counter electrode of the electrochemical cell is equal to the voltage magnitude required by the actual experiment.

[0049] Embodiment 4: This embodiment is basically the same as Embodiment 1, the difference being that: in this embodiment, as shown in FIG. 4(c), the capacitor discharge signal conditioning circuit includes a fifth resistor R5 and a third operational amplifier A3. The third operational amplifier A3 has a non-inverting input terminal, an inverting input terminal, and an output terminal. The non-inverting input terminal of the third operational amplifier A3 is the input terminal of the capacitor discharge signal conditioning circuit. The inverting input terminal of the third operational amplifier A3 is connected to one end of the fifth resistor R5, and the output terminal of the third operational amplifier A3 is connected to the other end of the fifth resistor R5, and the connection end is the output terminal of the capacitor discharge signal conditioning circuit.

[0050] In the capacitor discharge signal conditioning circuit of this embodiment, the fifth resistor R5 serves as a current limiting resistor to limit the current flowing into the third operational amplifier A3 and prevent the third operational amplifier A3 from being damaged due to excessive current flowing into it. The third operational amplifier A3 follows the potential change on the counter electrode of the electrochemical cell and outputs the followed voltage signal through its output terminal.

[0051] Embodiment 5: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, as shown in FIG. 4(d), the programmable gain I / V conversion circuit includes a fourth operational amplifier A4, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a four-way analog switch S1; the four-way analog switch S1 has four selection terminals, a common terminal, and two control terminals. The two control terminals of the four-way analog switch S1 are respectively used to access selection signals. Under the control of the selection signals accessed by the two control terminals, one of the four selection terminals of the four-way analog switch S1 is conducted with its common terminal, and the other three are cut off from its common terminal. The four selection terminals of the four-way analog switch S1 are respectively referred to as its first selection terminal, second selection terminal, third selection terminal, and fourth selection terminal, and the two control terminals of the four-way analog switch S1 are respectively referred to as its first control terminal and second control terminal; when the selection signals accessed by the first control terminal and the second control terminal of the four-way analog switch S1 are both low levels, its first selection terminal is conducted with its common terminal, while the second selection terminal, third selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signal accessed by the first control terminal of the four-way analog switch S1 is a low level and the selection signal accessed by the second control terminal is a high level, its second selection terminal is conducted with its common terminal, while the first selection terminal, third selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signal accessed by the first control terminal of the four-way analog switch S1 is a high level and the selection signal accessed by the second control terminal is a low level, its third selection terminal is conducted with its common terminal, while the first selection terminal, second selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signals accessed by the first control terminal and the second control terminal of the four-way analog switch S1 are both high levels, its fourth selection terminal is conducted with its common terminal, while the first selection terminal, second selection terminal, and third selection terminal are all cut off from its common terminal; the fourth operational amplifier A4 has a non-inverting input terminal, an inverting input terminal, and an output terminal;The non-inverting input terminal of the fourth operational amplifier A4 is grounded. The inverting input terminal of the fourth operational amplifier A4, one end of the sixth resistor R6, one end of the second capacitor C2, one end of the seventh resistor R7, one end of the third capacitor C3, one end of the eighth resistor R8, one end of the fourth capacitor C4, one end of the ninth resistor R9, and one end of the fifth capacitor C5 are connected, and their connection terminal is the input terminal of the programmable gain I / V conversion circuit. The other end of the sixth resistor R6 and the other end of the second capacitor C2 are connected to the first selection terminal of the four-way analog switch S1. The other end of the seventh resistor R7 and the other end of the third capacitor C3 are connected to the second selection terminal of the four-way analog switch S1. The other end of the eighth resistor R8 and the other end of the fourth capacitor C4 are connected to the third selection terminal of the four-way analog switch S1. The other end of the ninth resistor R9, the other end of the fifth capacitor C5, and the fourth selection terminal of the four-way analog switch S1 are connected. The common terminal of the four-way analog switch S1 is connected to the output terminal of the fourth operational amplifier A4, and its connection terminal is the output terminal of the programmable gain I / V conversion circuit. The first control terminal of the four-way analog switch S1 is the first control terminal of the programmable gain I / V conversion circuit; the second control terminal of the four-way analog switch S1 is the second control terminal of the programmable gain I / V conversion circuit.

[0052] In the programmable gain I / V conversion circuit of this embodiment, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 form a filter circuit for filtering out the noise signals in the signal output from the output terminal of the fourth operational amplifier A4. When both the fourth output terminal and the fifth output terminal of the microcontroller output low levels, at this time, the first selection terminal of the four-way analog switch S1 and its common terminal are conducted, and the second selection terminal, the third selection terminal, and the fourth selection terminal are all cut off from the common terminal. At this time, the amplification factor (i.e., the gain) of the programmable gain I / V conversion circuit is determined by the resistance value of the sixth resistor R6. When the fourth output terminal of the microcontroller outputs a low level and the fifth output terminal outputs a high level, at this time, the second selection terminal of the four-way analog switch S1 and the common terminal are conducted, and the first selection terminal, the third selection terminal, and the fourth selection terminal are all cut off from the common terminal. At this time, the amplification factor of the programmable gain I / V conversion circuit is determined by the resistance value of the seventh resistor R7. When the fourth output terminal of the microcontroller outputs a high level and the fifth output terminal outputs a low level, at this time, the third selection terminal of the four-way analog switch S1 and the common terminal are conducted, and the first selection terminal, the second selection terminal, and the fourth selection terminal are all cut off from the common terminal. At this time, the amplification factor of the programmable gain I / V conversion circuit is determined by the resistance value of the eighth resistor R8. When both the fourth output terminal and the fifth output terminal of the microcontroller output high levels, at this time, the fourth selection terminal of the four-way analog switch S1 and the common terminal are conducted, and the first selection terminal, the second selection terminal, and the third selection terminal are all cut off from the common terminal. At this time, the amplification factor of the programmable gain I / V conversion circuit is determined by the resistance value of the ninth resistor R9.

[0053] Accordingly, based on the gain setting instruction, the microcontroller outputs corresponding selection signals at its fourth output terminal and fifth output terminal to control the conduction or cut-off between the four selection terminals of the four-way analog switch S1 and its common terminal, thereby setting the amplification factor (gain) of the programmable gain I / V conversion circuit to output a signal according to the required gain.

[0054] To verify the performance of the transient potential scanning circuit for opto- and electro-catalytic reaction detection research of the present invention, the host computer sets the capacitor charging voltage value setting instruction, the capacitor discharging polarity setting instruction, and the gain setting instruction according to the detection operation requirements of the electrochemical cell, and collects the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit through an oscilloscope under different detection operation conditions o1 of the waveform diagram and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2 of the waveform diagram. Among them, a 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for opto- and electro-catalytic reaction detection research of the present invention, according to the capacitor charging voltage value setting instruction and the capacitor discharging polarity setting instruction, makes the voltage signal magnitude applied to the counter electrode of the electrochemical cell be +1 V, and when the gain set according to the gain setting instruction is 10 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 of the waveform diagram and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2 of the waveform diagram are shown in Fig. 5(a); a 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for opto- and electro-catalytic reaction detection research of the present invention, according to the capacitor charging voltage value setting instruction and the capacitor discharging polarity setting instruction, makes the voltage signal magnitude applied to the counter electrode of the electrochemical cell be +1 V, and when the gain set according to the gain setting instruction is 100 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 of the waveform diagram and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2 of the waveform diagram are shown in Fig. 5(b); a 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for opto- and electro-catalytic reaction detection research of the present invention, according to the capacitor charging voltage value setting instruction and the capacitor discharging polarity setting instruction, makes the voltage signal magnitude applied to the counter electrode of the electrochemical cell be -1 V, and when the gain set according to the gain setting instruction is 10 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 of the waveform diagram and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2The waveform diagram of [description] is shown in Figure 5(c); A 10 kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharging polarity setting command, such that when the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is -1 V and the gain set according to the gain setting command is 100 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 The waveform diagram of [description] and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2 The waveform diagram of [description] is shown in Figure 5(d); A series circuit of a 10 kΩ resistor and a 0.47 μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharging polarity setting command, such that when the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is +1 V and the gain set according to the gain setting command is 10 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 The waveform diagram of [description] and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2 The waveform diagram of [description] is shown in Figure 6(a); A series circuit of a 10 kΩ resistor and a 0.47 μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharging polarity setting command, such that when the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is +1 V and the gain set according to the gain setting command is 100 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 The waveform diagram of [description] and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2 The waveform diagram of [description] is shown in Figure 6(b); A series circuit of a 10 kΩ resistor and a 0.47 μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharging polarity setting command, such that when the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is -1 V and the gain set according to the gain setting command is 10 K, the voltage signal V output from the output terminal of the capacitor discharge signal conditioning circuit o1 The waveform diagram of [description] and the voltage signal V output from the output terminal of the programmable gain I / V conversion circuit o2The waveform diagram is shown in Figure 6(c); A series circuit of a 10kΩ resistor and a 0.47μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell. The microcontroller of the transient potential scanning circuit for opto-electrocatalytic reaction detection research of the present invention sets commands according to the capacitor charging voltage value and the capacitor discharging polarity setting command, so that when the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell is -1V and the gain set according to the gain setting command is 100K, the voltage signal V output from the output end of the capacitor discharge signal conditioning circuit o1 The waveform diagram of and the voltage signal V output from the output end of the programmable gain I / V conversion circuit o2 The waveform diagram is shown in Figure 6(d).

[0055] Analysis Figures 5(a) to 5(d) It can be known that: A 10kΩ resistor is between the counter electrode and the working electrode of the electrochemical cell. At this time, the simulated electrochemical cell parameters are set as a pure resistive load. When the voltage applied to the counter electrode of the electrochemical cell is +1V, the voltage signal V output from the output end of the capacitor discharge signal conditioning circuit of the transient potential scanning circuit for opto-electrocatalytic reaction detection research of the present invention o1 The waveform shows an exponential decay. When the gain changes from 10K to 100K, the voltage signal V output from the output end of the programmable gain I / V conversion circuit o2 The amplitude of the waveform increases significantly, which indicates that the programmable gain I / V conversion circuit effectively converts the weak current signal into a voltage signal for amplification. When the magnitude of the voltage signal applied to the counter electrode of the electrochemical cell changes from +1V to -1V, V o1 、V o2 will also have a corresponding inversion, which indicates that the capacitor polarity conversion circuit can achieve the positive / negative voltage switching function.

[0056] Analysis Figures 6(a) to 6(d) It can be known that: A series circuit of a 10kΩ resistor and a 0.47μF capacitor is connected between the counter electrode and the working electrode of the electrochemical cell to simulate the double-layer effect in actual opto-electrocatalytic reactions. At this time, the attenuation time of the voltage signal V output from the output end of the programmable gain I / V conversion circuit o1 is significantly longer than the attenuation time of the voltage signal V output from the output end of the programmable gain I / V conversion circuit when only a 10kΩ resistor is connected between the counter electrode and the working electrode of the electrochemical cell o1 This indicates that the transient potential scanning circuit for opto-electrocatalytic reaction detection research of the present invention can capture the dynamic response of complex electrochemical interfaces.

[0057] It can be seen from this that the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention can accurately capture transient voltage signals under different electrochemical cell parameters (pure resistive, RC series). These experimental results fully support the technological innovation of the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention in improving detection accuracy, simplifying the operation process, and real-time performance.

[0058] In summary, measuring the capacitor discharge by the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention can improve the accuracy of the capacitor charging voltage setting, and can reduce the detection difficulty of the weak current signal of the working electrode of the electrochemical cell. The detection operation process is simple and not prone to misoperation. By measuring the voltage and current signals of the electrochemical cell during capacitor discharge by the transient potential scanning circuit for the detection research of photo- and electro-catalytic reactions of the present invention, it provides a more accurate, simple to operate and cost-effective solution for analyzing the in-situ dynamics of charge distribution during different potentials and photocatalytic processes.

Claims

1. A transient potential scanning circuit for detecting photo- and electro-catalytic reactions, characterized in that It includes a numerically controlled capacitor charging circuit, a capacitor polarity conversion circuit, a capacitor discharge signal conditioning circuit, a programmable gain I / V conversion circuit, and a microcontroller. The capacitor polarity conversion circuit includes a first capacitor. The microcontroller can communicate with the host computer through a serial communication protocol, receive the capacitor charging voltage value setting instruction, the capacitor discharge polarity setting instruction, and the gain setting instruction set according to the detection operation requirements of the electrochemical cell at the host computer. After receiving the capacitor charging voltage value setting instruction, the capacitor discharge polarity setting instruction, and the gain setting instruction, it first outputs a corresponding voltage control signal to the numerically controlled capacitor charging circuit according to the capacitor charging voltage value setting instruction, so that the numerically controlled capacitor charging circuit outputs a voltage signal equal to the set value of the capacitor charging voltage to the capacitor polarity conversion circuit. Then, it outputs a polarity control signal according to the capacitor discharge polarity setting instruction to control the charging and the discharge polarity of the first capacitor, so that the voltage applied to the counter electrode of the electrochemical cell by the capacitor polarity conversion circuit is equal to the voltage value required by the actual experiment. The capacitor discharge signal conditioning circuit is used to follow the voltage applied to the counter electrode of the electrochemical cell by the capacitor polarity conversion circuit and generate a corresponding voltage signal for output. When the capacitor polarity conversion circuit applies a voltage to the counter electrode of the electrochemical cell, the microprocessor outputs a corresponding gain control signal according to the gain setting instruction to control the programmable gain I / V conversion circuit to convert the current signal of the working electrode of the electrochemical cell into a voltage signal for output according to the set gain.

2. The transient potential scanning circuit for opto-electrocatalytic reaction detection research according to claim 1, characterized in that The described numerically controlled capacitor charging circuit has an input terminal and an output terminal. The capacitor polarity conversion circuit has an input terminal, an output terminal, and two control terminals, which are respectively referred to as the first control terminal and the second control terminal. The capacitor discharge signal conditioning circuit has an input terminal and an output terminal. The programmable gain I / V conversion circuit has an input terminal, an output terminal, and two control terminals, which are respectively referred to as the first control terminal and the second control terminal. The microcontroller has an input terminal and five output terminals, which are respectively referred to as the first output terminal, the second output terminal, the third output terminal, the fourth output terminal, and the fifth output terminal. The input terminal of the microcontroller is used to connect to the host computer through the serial communication protocol. The first output terminal of the microcontroller is used to output a voltage control signal. The second output terminal and the third output terminal of the microcontroller are used to output polarity control signals. The fourth output terminal and the fifth output terminal of the microcontroller are used to output gain control signals. The input terminal of the numerically controlled capacitor charging circuit is connected to the first output terminal of the microcontroller. The output terminal of the numerically controlled capacitor charging circuit is used to output a voltage signal whose magnitude is equal to the set value of the capacitor charging voltage. The output terminal of the numerically controlled capacitor charging circuit is connected to the input terminal of the capacitor polarity conversion circuit. The first control terminal of the capacitor polarity conversion circuit is connected to the second output terminal of the microcontroller. The second control terminal of the capacitor polarity conversion circuit is connected to the third output terminal of the microcontroller. The output terminal of the capacitor polarity conversion circuit is connected to the counter electrode of the electrochemical cell. The input terminal of the capacitor discharge signal conditioning circuit is connected to the counter electrode of the electrochemical cell. The input terminal of the programmable gain I / V conversion circuit is connected to the working electrode of the electrochemical cell. The first control terminal of the programmable gain I / V conversion circuit is connected to the fourth output terminal of the microcontroller. The second control terminal of the programmable gain I / V conversion circuit is connected to the fifth output terminal of the microcontroller.

3. A transient potential scanning circuit for optoelectrocatalytic reaction detection research according to claim 2, characterized in that The described numerically controlled capacitor charging circuit includes a first resistor, a second resistor, a third resistor, a first operational amplifier, and a second operational amplifier. Both the first operational amplifier and the second operational amplifier have a non-inverting input terminal, an inverting input terminal, and an output terminal. One end of the first resistor is connected to the inverting input terminal of the first operational amplifier. The non-inverting input terminal of the first operational amplifier is the input terminal of the numerically controlled capacitor charging circuit. The other end of the first resistor, the output terminal of the first operational amplifier, and the non-inverting input terminal of the second operational amplifier are connected. The inverting input terminal of the second operational amplifier, one end of the second resistor, and one end of the third resistor are connected. The other end of the third resistor is grounded. The other end of the second resistor is connected to the output terminal of the second operational amplifier, and the connection end is the output terminal of the numerically controlled capacitor charging circuit.

4. The transient potential scanning circuit for opto-electrocatalytic reaction detection research according to claim 2, wherein The described capacitance polarity conversion circuit further includes a fourth resistor and two relays. Each relay has two normally open terminals, two normally closed terminals, two common terminals, and a control coil terminal. The two normally open terminals are respectively referred to as the first normally open terminal and the second normally open terminal. The two normally closed terminals are respectively referred to as the first normally closed terminal and the second normally closed terminal. The two common terminals are respectively referred to as the first common terminal and the second common terminal. The control coil terminal of the relay is used to receive a control signal. When the control signal received by the control coil terminal of the relay is at a high level, its first normally open terminal conducts with the first common terminal, its second normally open terminal conducts with the second common terminal, its first normally closed terminal is cut off from the first common terminal, and its second normally closed terminal is cut off from the second common terminal. When the control signal received by the control coil terminal of the relay is at a low level, its first normally open terminal is cut off from the first common terminal, its second normally open terminal is cut off from the second common terminal, its first normally closed terminal conducts with the first common terminal, and its second normally closed terminal conducts with the second common terminal. The two relays are respectively referred to as the first relay and the second relay. One end of the fourth resistor is the input terminal of the capacitance polarity conversion circuit. The other end of the fourth resistor is connected to the first normally closed terminal of the first relay. The second normally closed terminal of the first relay is grounded. One end of the first capacitor is connected to the first common terminal of the first relay. The other end of the first capacitor is connected to the second common terminal of the first relay. The first normally open terminal of the first relay is connected to the first common terminal of the second relay. The second normally open terminal of the first relay is connected to the second common terminal of the second relay. The first normally closed terminal of the second relay is connected to its second normally open terminal, and the connection end is the output terminal of the capacitance polarity conversion circuit. The first normally open terminal and the second normally closed terminal of the second relay are both grounded. The control coil terminal of the first relay is the first control terminal of the capacitance polarity conversion circuit. The control coil terminal of the second relay is the second control terminal of the capacitance polarity conversion circuit.

5. The transient potential scanning circuit for opto - electro - catalytic reaction detection research according to claim 2, wherein The described capacitance discharge signal conditioning circuit includes a fifth resistor and a third operational amplifier. The third operational amplifier has a non-inverting input terminal, an inverting input terminal, and an output terminal. The non-inverting input terminal of the third operational amplifier is the input terminal of the capacitance discharge signal conditioning circuit. The inverting input terminal of the third operational amplifier is connected to one end of the fifth resistor. The output terminal of the third operational amplifier is connected to the other end of the fifth resistor, and the connection end is the output terminal of the capacitance discharge signal conditioning circuit.

6. The transient potential scanning circuit for opto-electrocatalytic reaction detection research according to claim 2, wherein The described programmable gain I / V conversion circuit includes a fourth operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and a four-way analog switch; the four-way analog switch has four selection terminals, a common terminal, and two control terminals. The two control terminals of the four-way analog switch are respectively used to connect to selection signals. Under the control of the selection signals connected to the two control terminals, one of the four selection terminals of the four-way analog switch conducts with its common terminal, and the other three are cut off from its common terminal. The four selection terminals of the four-way analog switch are respectively referred to as its first selection terminal, second selection terminal, third selection terminal, and fourth selection terminal, and the two control terminals of the four-way analog switch are respectively referred to as its first control terminal and second control terminal; when the selection signals connected to the first control terminal and the second control terminal of the four-way analog switch are both at low level, its first selection terminal conducts with its common terminal, while the second selection terminal, third selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signal connected to the first control terminal of the four-way analog switch is at low level and the selection signal connected to the second control terminal is at high level, its second selection terminal conducts with its common terminal, while the first selection terminal, third selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signal connected to the first control terminal of the four-way analog switch is at high level and the selection signal connected to the second control terminal is at low level, its third selection terminal conducts with its common terminal, while the first selection terminal, second selection terminal, and fourth selection terminal are all cut off from its common terminal; when the selection signals connected to the first control terminal and the second control terminal of the four-way analog switch are both at high level, its fourth selection terminal conducts with its common terminal, while the first selection terminal, second selection terminal, and third selection terminal are all cut off from its common terminal; the fourth operational amplifier has a non-inverting input terminal, an inverting input terminal, and an output terminal;The non-inverting input terminal of the fourth operational amplifier is grounded. The inverting input terminal of the fourth operational amplifier, one end of the sixth resistor, one end of the second capacitor, one end of the seventh resistor, one end of the third capacitor, one end of the eighth resistor, one end of the fourth capacitor, one end of the ninth resistor, and one end of the fifth capacitor are connected, and the connection terminal is the input terminal of the programmable gain I / V conversion circuit. The other end of the sixth resistor and the other end of the second capacitor are connected to the first selection terminal of the four-way analog switch. The other end of the seventh resistor and the other end of the third capacitor are connected to the second selection terminal of the four-way analog switch. The other end of the eighth resistor and the other end of the fourth capacitor are connected to the third selection terminal of the four-way analog switch. The other end of the ninth resistor, the other end of the fifth capacitor, and the fourth selection terminal of the four-way analog switch are connected. The common terminal of the four-way analog switch is connected to the output terminal of the fourth operational amplifier, and the connection terminal is the output terminal of the programmable gain I / V conversion circuit. The first control terminal of the four-way analog switch is the first control terminal of the programmable gain I / V conversion circuit; the second control terminal of the four-way analog switch is the second control terminal of the programmable gain I / V conversion circuit.

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