A liquid layer controllable in-situ electrochemical surface enhanced infrared spectroscopy cell and a method for adjusting and indicating liquid layer parallelism

Abstract

The application relates to an electrochemical in-situ infrared spectrum cell, in particular to an in-situ electrochemical surface enhanced infrared spectrum cell with controllable liquid layer and a liquid layer parallelism adjusting and indicating method, which comprises a reaction cell, a counter electrode I, a counter electrode II and a reference electrode; a gold-plated microstructure silicon sheet is fixed at the bottom of the reaction cell; the counter electrode I, the reference electrode and the counter electrode II are fixed in the reaction cell, and the counter electrode I and the counter electrode II are arranged on the two sides of the gold-plated microstructure silicon sheet; the application further comprises an inclined plate I; the inclined plate I is fixed on the reaction cell through a horizontal adjusting screw I; the application further comprises a one-dimensional translation stage and a column; the one-dimensional translation stage is fixed on the inclined plate I through a connecting piece I, and the column is fixed with the one-dimensional translation stage through a connecting piece II; the column is arranged in alignment with the gold-plated microstructure silicon sheet. Compared with the prior art, the application realizes accurate control of the thickness and parallelism of an electrolyte layer, and can adjust the electrolyte layer according to the needs to obtain the required infrared spectrum at the electrode interface.

Description

Technical Field

[0001] This invention relates to an electrochemical in-situ infrared spectroscopy cell, specifically to a liquid-layer controllable in-situ electrochemical surface-enhanced infrared spectroscopy cell and a method for adjusting and indicating the parallelism of the liquid layer. Background Technology

[0002] The electrode / solution interface is the core site controlling and influencing the entire electrochemical reaction. A deep understanding of the reaction processes at the electrode / solution interface is crucial for both fundamental and applied electrochemical research. In-situ electrochemical attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) can provide chemical structural information at the electrode / solution interface. The ATR-SEIRAS technique mainly involves infrared crystalline silicon (as the working electrode, WE) with a metal thin film, a spectroscopic electrolytic cell, a reference electrode (RE), and a counter electrode (CE). ATR-SEIRAS utilizes the evanescent wave generated by total reflection of infrared light at the silicon crystal interface for detection. Furthermore, the surface-enhanced infrared absorption (SEIRA) effect of the conductive metal thin film on the infrared crystal (silicon) significantly increases the infrared absorption intensity of adsorbed reaction intermediates at the electrode-solution interface. However, due to the small penetration depth of the evanescent wave (<1 micrometer) and the unrestricted transport of reaction products, the electrochemical ATR-SEIRAS method struggles to detect near-interfacial solution phase species changes. It should be noted that obtaining structural information on both adsorbed species on the electrode surface and species in the solution phase simultaneously is essential for a comprehensive understanding of the electrochemical reaction mechanism.

[0003] As mentioned above, the existing electrochemical ATR-SEIRAS method generally cannot provide comprehensive information on adsorption intermediates and liquid-phase dissolution products of electrochemical interfacial reactions, which severely limits its application in the study of electrochemical reaction mechanisms. Summary of the Invention

[0004] The purpose of this invention is to solve at least one of the above problems by providing an in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable electrolyte layer and a method for adjusting and indicating the parallelism of the electrolyte layer, thereby achieving precise control of the electrolyte layer and allowing adjustment of the electrolyte layer thickness and parallelism as needed to obtain the required infrared spectrum.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] The first aspect of the present invention discloses an in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer, comprising an electrochemical infrared spectroscopy cell body, an electrolyte layer parallelism control device, and an electrolyte layer thickness control device.

[0007] The electrochemical infrared spectroscopy cell includes a reaction cell, counter electrode I, counter electrode II, and a reference electrode; a gold-plated microstructured silicon wafer used as a working electrode is fixedly disposed at the bottom of the reaction cell; the counter electrode I, the reference electrode, and the counter electrode II are respectively fixedly installed in the reaction cell, with the counter electrode I and the counter electrode II respectively disposed on both sides of the gold-plated microstructured silicon wafer.

[0008] The electrolyte layer parallelism control device includes an inclined plate I; the inclined plate I is fixed to the reaction tank by a horizontal adjusting screw I.

[0009] The electrolyte layer thickness control device includes a one-dimensional translation stage and a column; the one-dimensional translation stage is fixed to the inclined plate I via connector II, and the upper end of the column is fixedly connected to the one-dimensional translation stage via connector I; the lower end of the column is aligned with the gold-plated microstructure silicon wafer.

[0010] The one-dimensional translation stage moves the column, changing the distance between the bottom of the column and the gold-plated microstructure silicon wafer, thereby changing the thickness of the electrolyte layer.

[0011] The two counter electrodes (counter electrode I and counter electrode II) set in this infrared spectral cell are located on both sides of the gold-plated microstructured silicon wafer (working electrode), which can alleviate the uneven electric field distribution on the working electrode when the electrolyte layer is relatively thin. The reference electrode can be placed on either side of the gold-plated microstructured silicon wafer. On the one hand, the potential of the reference electrode is stable, and on the other hand, the current flowing through the reference electrode is negligible. Therefore, the presence of a reference electrode makes the potential applied to the working electrode more accurate.

[0012] By adjusting the height of the one-dimensional translation platform relative to connector II (for example, the one-dimensional translation platform and connector II are fixed by threads, so rotating the one-dimensional translation platform will change the height relative to connector II), the height of the electrolyte layer thickness control device is changed, that is, the distance between the column and the gold-plated microstructure silicon wafer (for the specific structure and preparation method of the gold-plated microstructure silicon wafer, please refer to Anal. Chem. 2017, 89, 11818-11824; J. Phys. Chem. Lett. 2020, 11, 8727-8734), the purpose of adjusting the electrolyte layer thickness is achieved.

[0013] The inclined plate is equipped with multiple leveling screws. By adjusting a single leveling screw, the levelness of the inclined plate can be changed. The levelness can be adjusted by adjusting each leveling screw according to the required levelness.

[0014] Preferably, the reaction cell consists of a lower reaction cell cover and an upper reaction cell cover that fits over the lower reaction cell cover, forming a cavity for containing the electrolyte between the upper reaction cell cover and the lower reaction cell cover; the gold-plated microstructured silicon wafer is fixedly disposed at the center of the bottom of the lower reaction cell cover, and the upper reaction cell cover has an opening at the corresponding position of the gold-plated microstructured silicon wafer for the passage of the column; the lower ends of the counter electrode I, the reference electrode, and the counter electrode II all extend into the cavity.

[0015] Preferably, the lower ends of counter electrode I and counter electrode II are turned within the cavity and extend above the side edge of the gold-plated microstructure silicon wafer. Positioning the lower ends of the counter electrodes as close as possible to the working electrode is intended to minimize the problem of uneven electric field distribution on the working electrode when the liquid layer thickness is relatively small.

[0016] Preferably, the upper and lower covers of the reaction tank are provided with annular sealing grooves, and O-rings are installed within the sealing grooves. This sealing prevents electrolyte leakage, thereby avoiding safety accidents.

[0017] Preferably, the reaction cell is made of PEEK material. PEEK (polyether ether ketone) material has many excellent properties such as good high temperature resistance, corrosion resistance and insulation stability, making it very suitable as a material for reaction cells that hold electrolyte and undergo electrochemical reactions.

[0018] Preferably, the column is made of PEEK material. PEEK (polyether ether ketone) material has many excellent properties such as high temperature resistance, corrosion resistance and insulation stability, making it very suitable as the column in this invention (which needs to pass through an electrolyte and has its bottom immersed in the electrolyte where an electrochemical reaction occurs).

[0019] Preferably, the electrolyte layer parallelism control device further includes a disc spring I, which is disposed between the inclined plate I and the reaction tank. The disc spring has a pre-tensioning function. By setting the disc spring between the inclined plate I and the reaction tank, a certain supporting resistance can be provided when adjusting the level of the inclined plate I by the leveling screw I, so that the adjustment can be precisely controlled and the level can be adjusted in place.

[0020] Preferably, the electrolyte layer thickness control device further includes a gold-plated plane mirror and an inclined plate II; the inclined plate II is fixed to the connecting piece I by a horizontal adjusting screw II, and the gold-plated plane mirror is fixedly installed on the inclined plate II; the gold-plated plane mirror is positioned directly above the column and is parallel to the bottom surface of the column. The gold-plated plane mirror can be used to calibrate the levelness of the bottom surface of the column, ensuring that the electrolyte layer thickness remains uniform, thereby obtaining accurate and reliable experimental results and infrared spectra.

[0021] Preferably, the electrolyte layer thickness control device further includes a disc spring II, which is disposed between the inclined plate II and the connecting member I. The disc spring has a pre-tensioning function. By setting the disc spring between the inclined plate II and the connecting member I, a certain supporting resistance can be provided when adjusting the level of the inclined plate II by the leveling screw II, so that the adjustment can be precisely controlled and the level adjustment can be ensured to be in place.

[0022] Preferably, the column body is further provided with an electrolyte channel; the outlet of the electrolyte channel is located at the center of the bottom of the column body.

[0023] Preferably, the electrolyte channel inlet is connected to a peristaltic pump. The peristaltic pump delivers the electrolyte into the reaction cell at a uniform speed through the electrolyte channel inlet, and the flow rate of the electrolyte can be effectively controlled as needed, thereby improving mass transfer at the working electrode and enabling adjustments to the measurement target in conjunction with height regulation.

[0024] A second aspect of this invention discloses a method for adjusting and indicating the parallelism of a liquid layer in an in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer as described above, comprising the following steps:

[0025] S1: Place the electrolyte layer thickness control device between a pair of lasers that are set opposite each other and whose emitted lasers are collinear. Adjust the horizontal adjustment screw II to change the level of the gold-plated plane mirror, so that the laser emitted by the lasers returns to the laser starting point under the reflection of the gold-plated plane mirror and the bottom surface of the column, thus completing the adjustment of the level of the gold-plated plane mirror.

[0026] S2: After the electrolyte layer thickness control device is installed on the inclined plate I, the whole assembly is placed in the adjustment optical path. By adjusting the horizontal adjustment screw I, the horizontality of the inclined plate I is changed, so that the laser emitted by the laser in the adjustment optical path returns to the laser starting point under the reflection of the gold-plated plane mirror, thus completing the adjustment of the horizontality of the controllable in-situ electrochemical surface-enhanced infrared spectroscopy cell of the electrolyte layer.

[0027] Before proceeding to step S2, the adjustment optical path needs to be calibrated to ensure that the laser starting point and laser ending point in the adjustment optical path coincide. The specific steps are as follows: place the in-situ electrochemical infrared spectroscopy cell in the laser adjustment optical path containing a 45° gold-plated plane mirror, and adjust the adjustment screw (fixed to the back of the 45° gold-plated plane mirror) to change the tilt of the 45° gold-plated plane mirror so that the laser emitted by the laser in the adjustment optical path returns to the laser starting point under the reflection of the gold-plated microstructure silicon wafer (the optical path can be simply described as laser - 45° gold-plated plane mirror - gold-plated plane mirror - 45° gold-plated plane mirror - laser).

[0028] Preferably, the adjustable optical path involves the laser beam emitted horizontally from the laser source. After reflection from the surface of a 45° gold-plated plane mirror positioned at a 45° angle, the beam is directed perpendicularly to the original optical path onto a horizontal reflecting surface (or a gold-plated microstructure silicon wafer). The horizontal reflecting surface is also perpendicular to the reflected optical path, thus the reflected optical path coincides with the original beam path. The beam is then reflected again from the surface of the 45° gold-plated plane mirror and returns to the laser's origin. Designing the adjustable optical path using reflection instead of direct beam effectively avoids the laser source being set too high, which would otherwise be inconvenient for users.

[0029] When using it, place the infrared spectral cell to be calibrated (with the electrolyte layer thickness control device installed) on the horizontal reflective surface. At this time, the reflective surface is a gold-plated plane mirror. Adjust the horizontal adjustment screw I according to the position of the returned laser until it coincides with the laser starting point. At this time, the level adjustment is completed, which can ensure the uniformity of the electrolyte layer thickness.

[0030] When the endpoint of the light path does not coincide with the starting point, adjust the adjusting screw fixed on the back of the 45° gold-plated plane mirror to make the endpoint of the light path coincide with the starting point, thus ensuring the effectiveness of the light path adjustment.

[0031] Preferably, laser I and laser II are 8m apart; laser III is at least 4m from the surface of the 45° gold-plated plane mirror. The 8m distance between the two lasers means that either laser is 4m from the reflecting surface. If the reflecting mirror is tilted, the longer the distance between the laser and the reflecting mirror, the farther the laser spot reflected by the mirror deviates from the laser's origin, making it easier to observe. Therefore, the greater the distance, the better. Considering the actual conditions of domestic laboratories, when the distance between the laser and the reflecting surface is 4m, a 1mm deviation between the laser's origin and return points results in a liquid layer parallelism deviation of approximately 1μm, which meets experimental requirements.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The electrolyte layer controllable spectral cell of the present invention is equipped with a liquid layer thickness adjustment device. The position of the PEEK cylinder (pillar) is controlled by a one-dimensional translation stage, thereby precisely controlling the thickness of the electrolyte layer. By adjusting the electrolyte layer thickness, 1) the signal of the solution phase product at the interface can be obtained without affecting the signal intensity of the adsorbed species at the interface surface; 2) the infrared absorption information of the adsorbed species at the interface surface and the solution phase species can be distinguished by adjusting the electrolyte layer thickness. Therefore, by reducing the liquid layer thickness, the simultaneous detection of adsorbed species at the interface surface and the solution phase species can be achieved; and by adjusting the electrolyte layer thickness, the information of solution phase species and adsorbed species at the interface can be distinguished.

[0034] (2) The controllable electrolyte layer spectral cell is equipped with a liquid layer parallelism adjustment device. The tilt (parallelism) of the PEEK cylinder is controlled by the cooperation of the tilt plate and the horizontal adjustment screw, so as to accurately control the uniformity of the electrolyte layer thickness and obtain a normal electrochemical response even when the electrolyte layer is thin.

[0035] (3) The controllable spectral cell of electrolyte layer is equipped with an electrolyte inlet. The flow rate of electrolyte in the electrolyte layer can be controlled by a peristaltic pump through the electrolyte inlet, thereby improving the mass transfer at the working electrode and obtaining information on the phase species of the solution at the electrode interface.

[0036] (4) The interference with the liquid phase product signal can be eliminated and the detection of surface species can be highlighted by increasing the liquid layer thickness and / or electrolyte flow rate as needed.

[0037] (5) In this invention, the controllable electrochemical infrared spectroscopy cell of electrolyte layer not only has the function of detecting the adsorbed species information on the electrode interface surface of the existing ATR-SEIRAS spectroscopy cell, but also can control the position of the PEEK cylinder by adjusting the one-dimensional translation stage, thereby precisely adjusting the thickness of the electrolyte layer.

[0038] (6) The present invention further provides a method for level adjustment indication. Utilizing the collimation property of laser, the level adjustment calibration of the infrared spectral cell of the present invention can be completed quickly and easily, thereby ensuring the uniformity of the electrolyte layer thickness during detection, improving the accuracy and authenticity of the data, and providing a solid foundation for further research and analysis. Furthermore, the level adjustment indication method provided by the present invention can also be used for level adjustment of related similar devices, demonstrating excellent practicality. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the liquid-layer controllable in-situ electrochemical surface-enhanced infrared spectroscopy cell of the present invention.

[0040] Figure 2 This is a schematic cross-sectional view of the electrochemical infrared spectroscopy cell of the present invention;

[0041] Figure 3 This is a schematic diagram illustrating the controllable in-situ electrochemical surface-enhanced infrared spectroscopy cell level adjustment of the present invention.

[0042] Figure 4 When using the liquid-layer-controlled in-situ electrochemical surface-enhanced infrared spectroscopy cell of the present invention, a) cyclic voltammetric curves of methanol electro-oxidation on Pt at different liquid layer thicknesses in 1M HClO4 solution; b) in-situ infrared spectral curves at 0.7V vs. Ag / AgCl potential;

[0043] Figure 5The following are examples of cyclic voltammetric curves for the electro-oxidation of methanol on Pt when using the liquid layer-controlled in-situ electrochemical surface-enhanced infrared spectroscopy cell of the present invention: a) Cyclic voltammetric curves for the electro-oxidation of methanol on Pt with a liquid layer thickness of 20 μm in 1M HClO4 solution; b) In-situ infrared spectra at different flow rates at 0.7 V vs. Ag / AgCl potential.

[0044] In the diagram: 1-Reaction cell; 2-Counter electrode I; 3-Reference electrode; 4-Counter electrode II; 5-Disc spring I; 6-Horizontal adjustment screw I; 7-Tilting plate I; 8-Connector I; 9-Connector II; 10-Disc spring II; 11-One-dimensional translation stage; 12-Horizontal adjustment screw II; 13-Gold-plated plane mirror; 14-Tilting plate II; 15-Electrolyte channel; 16-Cylinder; 101-Reaction cell top cover; 102-Reaction cell bottom cover; 103-Gold-plated microstructure silicon wafer; 104-O-ring seal; 301-Laser I; 302-Laser II; 303-Laser III; 304-45° gold-plated plane mirror; 305-Adjusting screw. Detailed Implementation

[0045] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0046] Example 1

[0047] A liquid-layer-controllable in-situ electrochemical surface-enhanced infrared spectroscopy cell, such as Figure 1 and Figure 2 As shown, it includes an electrochemical infrared spectroscopy cell, an electrolyte layer parallelism control device, and an electrolyte layer thickness control device;

[0048] The electrochemical infrared spectroscopy cell includes a reaction cell 1, a counter electrode I 2, a reference electrode 3, and a counter electrode II 4; a gold-plated microstructured silicon wafer 103 is fixedly disposed at the bottom of the reaction cell 1; the counter electrode I 2, the reference electrode 3, and the counter electrode II 4 are respectively fixedly installed in the reaction cell 1, and the counter electrode I 2 and the counter electrode II 4 are respectively disposed on both sides of the gold-plated microstructured silicon wafer 103.

[0049] The electrolyte layer parallelism control device includes an inclined plate I7; the inclined plate I7 ​​is fixed to the reaction tank 1 by a horizontal adjusting screw I6;

[0050] The electrolyte layer thickness control device includes a one-dimensional translation stage 11 and a column 16; the one-dimensional translation stage 11 is fixed to the inclined plate I7 ​​by a connector II9, and the column 16 is fixedly connected to the one-dimensional translation stage 11 by a connector I8; ​​the column 16 is aligned with the gold-plated microstructure silicon wafer 103.

[0051] The one-dimensional translation stage 11 moves the column 16, changing the distance between the bottom of the column 16 and the gold-plated microstructure silicon wafer 103, thereby changing the thickness of the electrolyte layer.

[0052] More specifically, in this embodiment:

[0053] The reaction tank 1 consists of an upper cover 101 covering a lower cover 102. A gold-plated microstructure silicon wafer 103 is fixed at the center of the bottom of the lower cover 102. Figure 2 As shown, the lower cover 102 of the reaction tank 1 gradually thickens outward from the gold-plated microstructure silicon wafer 103, forming a certain slope to facilitate the entry of infrared light; the upper cover 101 of the reaction tank 1 has a circular through hole at the corresponding position of the gold-plated microstructure silicon wafer 103 for the bottom of the column 16 to pass through. The upper cover 101 and the lower cover 102 of the reaction tank 1 have sealing grooves at corresponding positions on the sides of their contacting surfaces, and O-rings 104 are filled in the sealing grooves to ensure the sealing performance after the covers are closed. After the reaction cell 1 is covered and fixed, a cavity is formed inside. This cavity is used to hold the electrolyte. The lower ends of the reference electrode 3, counter electrode I2, and counter electrode II4 all extend through the top cover 101 of the reaction cell 1 into the cavity to be immersed in the electrolyte. The counter electrode I2 and counter electrode II4 are respectively disposed on both sides of the gold-plated microstructure silicon wafer 103, while the reference electrode 3 is disposed on the same side of the gold-plated microstructure silicon wafer 103 as the counter electrode I2. The reference electrode 3, counter electrode I2, microstructure chip, and counter electrode II4 are arranged in a basically straight line.

[0054] The inclined plate I7 ​​is L-shaped (its lengths on both sides match the dimensions of the reaction tank 1). It is screwed to the reaction tank 1 by three horizontal adjusting screws I6. Two disc springs I5 are installed below the center of each of the two sides of the inclined plate I7. The lower end of the disc springs I5 abuts against the upper surface of the cover 101 of the reaction tank 1, and the upper part abuts against the lower surface of the inclined plate I7. A certain preload is set to provide a certain support force for the inclined plate I7. In this way, when the horizontality is adjusted by the horizontal adjusting screws I6, there is a certain mutual constraint, making the adjustment range more controllable and the adjustment result more accurate.

[0055] The one-dimensional translation stage 11 is fixed to the inclined plate 17 via connector II9. The one-dimensional translation stage 11 and connector II9 are installed by threaded connection. Connector II9 is ​​L-shaped in general, and the one-dimensional translation stage 11 is threaded onto its upper vertical section. The inclined plate 17 is fixedly installed to its lower horizontal section (or bolted). Connector I8 is fixedly connected to the bottom of the one-dimensional translation stage 11. Connector I8 has an L-shaped cross-section. The inclined plate II14 is fixedly installed on the upper surface of the horizontal section of connector I8 by three horizontal adjusting screws II12. A pre-tightened disc spring II10 is also abutted between the inclined plate II14 and connector I8, and its function is the same as that of disc spring I5. A gold-plated plane mirror 13 (mirror surface facing upward) is also fixedly installed at the center of the upper surface of the inclined plate II14. The gold-plated plane mirror 13 can be used to assist in calibrating the levelness of the column 16. A column 16 is positioned below the horizontal section of connector I8. The bottom of column 16 passes through a through-hole in the top cover 101 of reaction tank 1 and extends into the cavity of reaction tank 1, aligning with the gold-plated microstructure silicon wafer 103. An electrolyte channel 15 is formed inside column 16, with an inlet on the upper sidewall and an outlet at the center of the bottom surface. Electrolyte can enter the cavity through this channel 15. Furthermore, the inlet of the electrolyte channel 15 is connected to a peristaltic pump via a pipe, allowing control of the electrolyte flow rate into the cavity of reaction tank 1. It should be noted that the gold-plated plane mirror 13 is positioned directly above column 16 and is parallel to the bottom surface of column 16 during use (adjustable via levelness calibration). An electrolyte outlet (i.e.,...) is also provided on the upper part of the reference electrode 3 and counter electrode II 4. Figure 1 The cubic block fixed on the reference electrode 3 and the counter electrode II 4 has an interface at its front end that is the outlet of the electrolyte. It is used to discharge the electrolyte in the cavity of the reaction tank (extracted by an externally connected peristaltic pump). It and the electrolyte channel 15 can form an electrolyte passage.

[0056] In this embodiment, the reaction tank 1 (including the upper cover 101 and the lower cover 102 of the reaction tank 1) and the column 16 are both made of PEEK material. Since PEEK itself has many excellent properties, it is suitable for application in electrochemical environments such as those described in this invention.

[0057] In this embodiment, the one-dimensional translation stage 11 moves at a height relative to the connector II 9 (achieved through threaded engagement), thereby causing the column 16 to move vertically, thus changing the distance between the bottom surface of the column 16 and the gold-plated microstructure silicon wafer 103, i.e., changing the thickness of the electrolyte layer.

[0058] When the electrolyte layer thickness decreases, the thin liquid layer structure restricts mass transfer, enriching the solution-phase products generated during the electrochemical reaction within the thin liquid layer and thus increasing their concentration, which is more conducive to the infrared detection of solution-phase species. Conversely, when the liquid layer thickness or flow rate is significantly increased, the spectral peaks of the liquid-phase products rapidly decrease or even disappear due to the significantly enhanced mass transfer, while the peak intensity of surface-adsorbed species remains almost unchanged. By observing the effect of liquid layer thickness or flow rate on the peak signal intensity, the peak assignments of intermediate surface species and liquid-phase products can be confirmed.

[0059] Before use, the in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable electrolyte layer provided in this embodiment needs to be calibrated for levelness to ensure the uniformity of electrolyte layer thickness during testing. The specific steps are as follows:

[0060] like Figure 3 As shown in Figure a, the lasers emitted by laser I 301 and laser II 302, which are 8m apart, are first adjusted to be collinear. Then, the electrolyte layer thickness control device is placed in the collinear visible laser path. The horizontal adjustment screw II 12 is adjusted so that the two laser beams return to their respective starting points after passing through the reflective surface (gold-plated plane mirror 13 and the bottom surface of column 16). At this time, the gold-plated plane mirror 13 and the bottom surface of column 16 have been adjusted to be parallel.

[0061] like Figure 3 As shown in Figure b, the horizontally positioned laser III 303 emits a laser beam. After reflection from the 45° surface of the 45° gold-plated plane mirror 304 (the 45° gold-plated plane mirror 304 is at least 4m away from the laser III 303), the beam is perpendicularly incident on the gold-plated microstructure silicon wafer (horizontal reflective surface) and reflects again. Due to the perpendicularity of the two beams, the reflected light coincides with the incident light (the light incident on the gold-plated microstructure silicon wafer). The reflected light returns to the laser's starting point after being reflected again by the surface of the 45° gold-plated plane mirror 304. Observe whether the laser's starting point and ending point coincide. If they do not coincide, adjust the adjusting screw 305 to make them coincide, ensuring the effectiveness of the adjustment of the optical path itself.

[0062] like Figure 3 As shown in Figure c, after fixing the electrolyte layer thickness control device onto the inclined plate I7, it is placed together in the adjustment optical path as a whole. At this time, the reflecting surface is the gold-plated plane mirror 13. Adjust the horizontal adjustment screw I6 to adjust the horizontality of the inclined plate I7 ​​so that the laser returns to the laser starting point (the starting point and the ending point coincide). At this time, the horizontality adjustment of the inclined plate I7 ​​is completed, and the controllable in-situ electrochemical surface-enhanced infrared spectral cell of the electrolyte layer is also adjusted at the same time.

[0063] like Figure 4Figure a shows the cyclic voltammetric current response of a Pt thin-film electrode in 1M HClO4 solution with different liquid layer thicknesses when using this device, with a scan rate of 2 mV / s. -1 It can be seen that by adjusting the parallelism of the electrolyte layer, a normal electrochemical response can be obtained even when the electrolyte layer is relatively thin; for example... Figure 4 Figure b shows the infrared spectra of methanol electro-oxidation at different liquid layer thicknesses in 1M HClO4 solution with a Pt thin film electrode at a potential of 0.7V vs. Ag / AgCl when using this device. It can be seen that as the thickness of the electrolyte layer decreases, the infrared absorption signal of the solution phase species gradually increases, and the best infrared detection signal of the solution phase species is obtained when the liquid layer thickness is 20μm. This indicates that the present invention can (1) obtain the signal of the solution phase product at the interface without affecting the signal intensity of the adsorbed species at the interface surface, and (2) distinguish the infrared absorption information of the adsorbed species at the interface surface and the solution phase species by adjusting the thickness of the electrolyte layer.

[0064] like Figure 5 Figure a shows the cyclic voltammetric current response of a Pt thin-film electrode in a 1M HClO4 solution with a liquid layer thickness of 20 μm at different flow rates during the electro-oxidation of methanol using this device. The scan rate is 2 mV / s. -1 The increased flow rate improved the mass transfer of the thin liquid layer, and the Faraday current of methanol electro-oxidation on Pt increased with increasing flow rate; for example... Figure 5 As shown in b, when using this device, the flow rates (from top to bottom corresponding to 0, 5, and 50 μL / min) at a liquid layer thickness of 20 μm in a 1M HClO4 solution under a potential of 0.7 V vs. Ag / AgCl are different. -1 The infrared spectroscopy results of methanol electro-oxidation on a Pt thin film electrode show that 5 μL min -1 At a flow rate of [specific flow rate], mass transfer in the thin liquid layer was improved, and infrared detection signals of solution phase species were also detected.

[0065] As described above, by adjusting the liquid layer thickness, infrared absorption information of surface-adsorbed species and solution-phase species at the interface can be obtained; further, by changing the electrolyte flow rate, mass transfer in the thin liquid layer can be improved, thereby obtaining more accurate detection results. Therefore, the liquid-layer-controllable in-situ electrochemical surface-enhanced infrared spectroscopy cell provided by this invention has high practicality and lays the foundation for the further development of electrochemical in-situ infrared spectroscopy detection technology.

[0066] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A liquid-layer controllable in-situ electrochemical surface-enhanced infrared spectroscopy cell, characterized in that, It includes an electrochemical infrared spectroscopy cell, an electrolyte layer parallelism control device, and an electrolyte layer thickness control device; The electrochemical infrared spectroscopy cell includes a reaction cell (1), a counter electrode I (2), a counter electrode II (4), and a reference electrode (3); a gold-plated microstructured silicon wafer (103) is fixedly disposed at the bottom of the reaction cell (1); the counter electrode I (2), the reference electrode (3), and the counter electrode II (4) are respectively fixedly installed in the reaction cell (1), and the counter electrode I (2) and the counter electrode II (4) are respectively disposed on both sides of the gold-plated microstructured silicon wafer (103); The electrolyte layer parallelism control device includes an inclined plate I (7); the inclined plate I (7) is fixed to the reaction tank (1) by a horizontal adjusting screw I (6); The electrolyte layer thickness control device includes a one-dimensional translation stage (11) and a column (16); the one-dimensional translation stage (11) is fixed to the inclined plate I (7) by a connector II (9), and the column (16) is fixedly connected to the one-dimensional translation stage (11) by a connector I (8); the column (16) is aligned with the gold-plated microstructure silicon wafer (103); the electrolyte layer thickness control device also includes a gold-plated plane mirror (13) and an inclined plate II (14); the inclined plate II (14) is fixed to the connector I (8) by a horizontal adjusting screw II (12), and the gold-plated plane mirror (13) is fixedly installed on the inclined plate II (14); the gold-plated plane mirror (13) is located directly above the column (16), and the gold-plated plane mirror (13) is parallel to the bottom surface of the column (16). The one-dimensional translation stage (11) moves the column (16), changing the distance between the bottom of the column (16) and the gold-plated microstructure silicon wafer (103), thereby changing the thickness of the electrolyte layer.

2. The in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer according to claim 1, characterized in that, The reaction cell (1) consists of a lower cover (102) and an upper cover (101) that covers the lower cover (102). The upper cover (101) and the lower cover (102) form a cavity for containing electrolyte. The gold-plated microstructure silicon wafer (103) is fixedly disposed at the bottom center of the lower cover (102). The upper cover (101) has an opening at the corresponding position of the gold-plated microstructure silicon wafer (103) for the passage of the column (16). The lower ends of the counter electrode I (2), the reference electrode (3) and the counter electrode II (4) all extend into the cavity.

3. The in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer according to claim 2, characterized in that, The upper cover (101) and lower cover (102) of the reaction tank are provided with annular sealing grooves, and O-rings (104) are provided in the sealing grooves.

4. The in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer according to claim 1, characterized in that, The reaction tank (1) and column (16) are made of PEEK material.

5. The in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer according to claim 1, characterized in that, The electrolyte layer parallelism control device also includes a disc spring I (5), which is abutted between the inclined plate I (7) and the reaction tank (1).

6. The in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer according to claim 1, characterized in that, The electrolyte layer thickness control device further includes a disc spring II (10), which is abutted between the inclined plate II (14) and the connector I (8).

7. The in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer according to claim 1, characterized in that, The column (16) is also provided with an electrolyte channel (15); the outlet of the electrolyte channel (15) is located at the center of the bottom of the column (16).

8. The in-situ electrochemical surface-enhanced infrared spectroscopy cell with controllable liquid layer according to claim 7, characterized in that, The inlet of the electrolyte channel (15) is connected to the peristaltic pump.

9. A method for adjusting and indicating the parallelism of a liquid layer, characterized in that, The method for adjusting and indicating the liquid layer parallelism of the in-situ electrochemical surface-enhanced infrared spectroscopy cell with liquid layer controllability as described in any one of claims 1-8 includes the following steps: S1: Place the electrolyte layer thickness control device between a pair of lasers that are set opposite each other and whose emitted lasers are collinear. Adjust the horizontal adjustment screw II (12) to change the level of the gold-plated plane mirror (13), so that the laser emitted by the lasers returns to the laser starting point under the reflection of the gold-plated plane mirror (13) and the bottom surface of the column (16), thus completing the adjustment of the level of the gold-plated plane mirror (13). S2: After the electrolyte layer thickness control device is installed on the inclined plate I (7), the whole device is placed in the adjustment optical path. The horizontality of the inclined plate I (7) is changed by adjusting the horizontal adjustment screw I (6), so that the laser emitted by the laser in the adjustment optical path returns to the laser starting point under the reflection of the gold-plated plane mirror (13), thus completing the adjustment of the horizontality of the liquid layer controllable in-situ electrochemical surface-enhanced infrared spectral cell.

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