A dynamic coating machine for disc electrodes

Abstract

The application belongs to the technical field of surface liquid coating, and particularly relates to a disc electrode dynamic coating machine, which comprises a power device and a rotating base, the power device is used for driving the rotating base to rotate, the rotating base comprises an electrode liner, the electrode liner is used for clamping a disc electrode and driving the disc electrode to rotate, and the rotating base further comprises a shell body, and the power device is installed in the shell body. The disc electrode is uniformly rotated by the power device, the centrifugal force is matched with the liquid surface tension, the capillary force and the evaporation rate, the catalyst dispersion liquid is uniformly distributed on the surface of the disc electrode, and finally the catalyst layer is uniformly coated on the disc electrode.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of surface liquid coating, and particularly relates to a dynamic coating machine for a disc electrode. BACKGROUND

[0002] The test of electrochemical catalyst is an experiment often done in the field of electrochemical research, which is used to test the electrochemical performance of the catalyst, such as the activity and stability of the catalyst material. In the traditional use process, the solid catalyst sample to be tested needs to be first dispersed in a mixed solution of a specific solvent and a binder by ultrasonic, and then is statically drop-coated on the surface of a disc electrode. After the solvent is evaporated, the solid sample will be distributed on the surface of the disc electrode. Due to the influence of liquid capillary force, solvent surface tension and evaporation rate, it is difficult to obtain a uniform thickness distribution of the catalyst sample on the surface of the disc electrode in the static drop-coating, and there is often a large difference in thickness distribution at different positions, which in turn affects the results of the electrochemical test and cannot achieve the limiting current density of the electrode reaction. The catalyst layer sample with uneven thickness will reduce the consistency of the electrochemical test data, making the data difficult to repeat and reducing the reliability of the data. At the same time, the problem of uneven thickness of the catalyst layer obtained by static drop-coating will also cause the catalyst to exhibit lower activity and stability in the test. Therefore, how to realize the uniform distribution of the catalyst sample on the surface of the disc electrode after coating and achieve the uniform thickness of the catalyst layer at different positions has important significance for ensuring the consistency, repeatability and reliability of the electrochemical test results. SUMMARY

[0003] The present application provides a dynamic coating machine for a disc electrode to solve the above problems.

[0004] To achieve the above purpose, the present application adopts the following technical scheme:

[0005] The dynamic coating machine for a disc electrode comprises a power device and a rotating base, the power device is used to drive the rotating base to rotate, the rotating base is used to clamp the disc electrode and drive the disc electrode to rotate, thereby completing the uniform coating of the disc electrode.

[0006] Further, the dynamic coating machine for a disc electrode further comprises a shell body, and the power device is installed inside the shell body.

[0007] Still further, the rotating base comprises an electrode bushing, and the electrode bushing is used to clamp the disc electrode and drive the disc electrode to rotate.

[0008] Still further, the rotating base further comprises a bearing seat, the bearing seat is installed on the shell body, a bearing is installed in the bearing seat, and the electrode bushing is installed inside the bearing.

[0009] Further, the bearing has two groups, which are axially installed in the bearing seat, and the electrode bushing is supported by the two groups of bearings to ensure the coaxiality of the electrode bushing during rotation, and effectively improve the stability of the rotation of the electrode bushing.

[0010] Further, the power device drives the electrode bushing to rotate through soft transmission.

[0011] Further, a rotating disc is installed at the output end of the power device, and a transmission chassis is arranged above the rotating disc, the rotating disc is connected with the transmission chassis through a spring, and power transmission through the spring can eliminate the eccentric motion influence caused by the vibration of the power device and the non-complete coaxiality of the installation position of the power device and the electrode bushing, so that the electrode bushing is more stable during rotation.

[0012] Further, the transmission chassis and the electrode bushing are connected in an interference fit embedding mode.

[0013] Further, a plurality of counterbores are arranged at the bottom of the electrode bushing, and a plurality of bosses corresponding to the counterbores are arranged on the transmission chassis.

[0014] Further, the transmission chassis and the electrode bushing are an integral structure.

[0015] Further, the electrode bushing is made of plastic material, which can effectively avoid the influence of contact pollution on the disc electrode experiment.

[0016] Further, the electrode bushing is made of PTFE polytetrafluoroethylene material.

[0017] Further, a limiting shoulder for limiting and clamping the disc electrode is arranged on the upper surface of the transmission chassis.

[0018] Further, the control assembly is further arranged, which is used for controlling the rotation speed of the power device.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] 1、The power device drives the disc electrode to rotate at a constant speed, and the centrifugal force is matched with the liquid surface tension, capillary force and evaporation rate, so that the catalyst dispersion liquid is uniformly distributed on the surface of the disc electrode, and finally the catalyst layer is uniformly coated on the disc electrode.

[0021] 2、The electrode bushing is nested in the double-bearing base structure, which improves the rotation coaxiality and stability of the disc electrode during the rotation of the electrode bushing, so as to ensure the uniformity of the thickness of the catalyst layer obtained when the electrode coating liquid sample is coated.

[0022] 3. By setting up a soft transmission structure, this invention reduces the vibration and axial position deviation at the output end of the power device, thereby improving the coaxiality of the electrode bushing during rotation and ensuring the consistency of experimental data unaffected by external factors.

[0023] 4. The present invention improves the reliability of transmission by using the interference fit between the transmission chassis and the electrode bushing, as well as the boss and countersunk hole structure, to transmit rotational power to the electrode bushing more stably. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention;

[0025] Figure 2 This is a front view of the present invention;

[0026] Figure 3 For the present invention Figure 2 Sectional view of section AA;

[0027] Figure 4 For the present invention Figure 3 A magnified view of a portion of circle A in the center;

[0028] Figure 5 For the present invention Figure 2 Sectional view of section BB;

[0029] Figure 6 A schematic diagram of the disk electrode and its working position;

[0030] Figure 7 Schematic diagram of disk electrode coating;

[0031] Figure 8 This is a static diagram of the catalyst dispersion on the surface of the disc electrode.

[0032] Figure 9 Image showing the evaporation of the catalyst dispersion on the surface of the disc electrode;

[0033] Figure 10 This is a distribution diagram of the catalyst surface after dynamic coating using the present invention;

[0034] Figure 11 This is a distribution diagram of the catalyst surface on the electrode prepared by the static drop-coating method;

[0035] Figure 12 Half-wave potential diagrams of electrode polarization curves for dynamic coating and static drop coating;

[0036] Figure 13 The polarization curves of five sets of repeatable experimental electrodes for static drop coating are shown.

[0037] Figure 14 Polarization curves of five sets of repeatable experimental electrodes for dynamic coating;

[0038] In the figure, power device 1, rotating base 2, shell body 3, rotating disc 4, magnet 5, transmission chassis 6, spring 7, control assembly 8, electrode bushing 201, bearing seat 202, bearing 203. DETAILED DESCRIPTION

[0039] In order to further illustrate the technical solutions of the present application, the present application will be further described below through examples.

[0040] As Figures 1 to 5 shown, a disc electrode dynamic coating machine, comprising a power device 1, a rotating base 2, a shell body 3 and a control assembly 8, the rotating base 2 comprises an electrode bushing 201 and a bearing seat 202, the bearing seat 202 is installed on the shell body 3, a bearing 203 is installed in the bearing seat 202, the bearing 203 has two groups, which are installed in the bearing seat 202 in the axial direction, and the electrode bushing 201 is supported by the two groups of bearings 203 to ensure the coaxiality of the electrode bushing 201 during rotation, effectively improving the stability of the rotation of the electrode bushing 201, the electrode bushing 201 is installed inside the bearing 203, the electrode bushing 201 is used for clamping the disc electrode and driving the disc electrode to rotate, the electrode bushing 201 is made of PTFE (polytetrafluoroethylene), which can effectively avoid the experimental influence of contact pollution on the disc electrode, the power device 1 is installed inside the shell body 3, a rotating disc 4 is installed at the output end of the power device 1, a transmission chassis 6 is provided above the rotating disc 4, the rotating disc 4 is connected with the transmission chassis 6 through a spring 7, and power transmission through the spring 7 can eliminate the eccentric motion influence caused by the vibration of the power device 1 and the non-complete coaxiality of the installation position of the power device 1 and the electrode bushing 201, so that the electrode bushing 201 is more stable during rotation, the transmission chassis 6 and the electrode bushing 201 are connected in an interference fit embedding mode, a plurality of counterbores are provided at the bottom of the electrode bushing 201, a plurality of bosses corresponding to the counterbores are provided on the transmission chassis 6, and a limiting shoulder for limiting and clamping the disc electrode is provided on the upper surface of the transmission chassis 6, the control assembly 8 is used for controlling the rotation speed of the power device 1.

[0041] In the above examples, the transmission chassis 6 can also be an integral structure with the electrode bushing 201.

[0042] Principle of operation: the experimental disc electrode embedded in the electrode bushing 201 hole to the shoulder limit surface of the transmission chassis 6, and then through the control assembly 8 in the shell body 3 to start the power device 1, the rotating disc 4 at the output end of the power device 1 will rotate power through the spring 7 to the transmission chassis 6, the transmission chassis 6 drives the electrode bushing 201 to rotate, and the electrode bushing 201 rotates in the double bearing seat structure of the bearing 203 and the bearing seat 201, and by adjusting the rotation speed of the power device 1, the disc electrode in the electrode bushing 201 rotates at a constant speed, so that the liquid sample dropped on the disc electrode spreads uniformly on the surface of the disc electrode, and the dried catalyst layer is uniformly distributed on the surface of the disc electrode, so that the catalyst layer is uniformly distributed, and the difference in the thickness direction Z axis of the surface dispersion layer is 2-3 nm, which can meet the ideal rotating disc electrode mass transfer diffusion control reaction model.

[0043] As shown in Figure 10 , using the dynamic coating of the commercial Pt / C catalyst according to the present application, the catalyst layer can be uniformly distributed, and the difference in the thickness direction Z axis of the surface dispersion layer is 2-3 nm, which can meet the ideal rotating disc electrode mass transfer diffusion control reaction model; as shown in Figure 11 , using static drop coating, the catalyst is not evenly covered and is easy to agglomerate, and the deviation in the thickness direction Z axis of the surface dispersion layer is 10-13 nm, which deviates from the ideal mass transfer model and is difficult to achieve the research purpose.

[0044] According to the oxygen reduction limiting current density formula: j D =0.62nFD0 2 / 3 ν -1 / 6 ω 1 / 2 C0 * , the theoretical limiting current density value of the above-mentioned test of the commercial Pt / C catalyst is 5.60mA cm -2 . Wherein j D is the limiting current density, n is the number of electron transfer in the oxygen reduction process, F is the Faraday constant (96485 C / mol), C0 * represents the saturation solubility of oxygen in the electrolyte solution, D0 represents the diffusion coefficient of the electrolyte solution, ω represents the rotation speed, and ν is the dynamic viscosity of the electrolyte.

[0045] As shown in Figure 12 , in the test of the commercial Pt / C catalyst, the half-wave potential of the dynamic coating disc electrode is 0.88V, and the limiting current density is 5.64mA cm -2 ; the half-wave potential of the disc electrode prepared by static drop coating is only 0.85V, and the limiting current density is 5.18mA cm -2 , which are all less than the data of the electrode prepared by dynamic coating. It can be seen that the electrode prepared by dynamic coating can reach the theoretical limiting current density, while the limiting current density of the electrode prepared by static drop coating is lower than the theoretical value, which cannot meet the research needs.

[0046] Figure 13 、 14 The polarization curves of the five sets of repetitive electrodes tested by static drop coating and dynamic coating are shown in Figures 1 and 2, respectively. According to the analysis of the polarization curve data, the half-wave potential value, mass activity, specific surface area activity, and limiting current density data can be obtained and statistically analyzed, and the results are shown in Tables 1 and 2.

[0047] The average half-wave potential of the polarization curve of the electrode prepared by using the dynamic coating electrode device of the application is 0.88 V, which is higher than the average half-wave potential of the static drop coating electrode (0.848 V), and the relative standard deviation of the former is smaller (Tables 1 and 2).

[0048] Similarly, the average limiting current density of oxygen reduction of the dynamic coating electrode is 5.62 mA cm -2 , which is higher than the limiting current density (5.24 mA cm -2 ) measured by the traditional static drop coating electrode, and the relative standard deviation of the former is smaller, the results are more consistent, and are closer to the theoretical limiting current density (Tables 1 and 2).

[0049] Generally, the specific surface activity and mass specific activity are used to evaluate the performance of the catalyst. When the commercial 20% Pt / C catalyst is tested by the dynamic coating electrode method of the application, the average mass specific activity and specific surface activity of the commercial 20% Pt / C catalyst at 0.9 V are 0.26 A mg -1 and 0.30 mA cm -2 , respectively. When the commercial 20% Pt / C catalyst is tested by the traditional static drop coating electrode, the average mass specific activity and specific surface activity of the commercial 20% Pt / C catalyst are 0.12 A mg -1 and 0.24 mA cm -2 , respectively, which are lower than the results measured by using the dynamic coating electrode of the application, and the relative standard deviation of the mass specific activity and specific surface activity data of the former is smaller (Tables 1 and 2).

[0050] It can be seen that compared with the static drop coating electrode, the electrode prepared by using the dynamic coating method of the application has higher consistency of electrochemical performance data and better repeatability, and can reach the theoretical limiting current density, and the half-wave potential, mass specific activity, and specific surface activity are higher than the measurement results of the static drop coating electrode, so the electrode prepared by using the dynamic coating device of the disc electrode is better and can better reflect the catalytic performance of the catalyst.

[0051] Table 1 is a polarization data table of five sets of repetitive electrodes for dynamic coating

[0052]

[0053] Table 1 and Table 2 are polarization data tables of five sets of repetitive electrodes for static drop coating

[0054]

[0055] Table 2

[0056] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and operation described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the claims below and their equivalents. What is claimed is:

[0057] Furthermore, it should be appreciated that a presently described embodiment is merely illustrative of the principles of the application. Therefore, the scope of the application should be determined by the following claims and their equivalents rather than by the above description. Moreover, the description herein is intended to enable any person skilled in the art to make and use the application, and the general principles described herein can be applied to other embodiments and applications without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the exemplary embodiments described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dynamic disc electrode coater characterized by: Including power device (1), rotating base (2) and control assembly (8), the power device (1) is used to drive rotating base (2) to rotate, the rotating base (2) is used to clamp disc electrode and drive disc electrode to rotate, so that the uniform coating work of disc electrode is completed, the rotating base (2) includes electrode bushing (201), the electrode bushing (201) is used to clamp disc electrode and drive disc electrode to rotate, the power device (1) drives electrode bushing (201) to rotate by soft transmission, the rotating disc (4) is installed at the output end of the power device (1), the transmission chassis (6) is arranged above the rotating disc (4), the rotating disc (4) is connected with transmission chassis (6) by spring (7), power transmission by spring (7) can eliminate the eccentric motion influence caused by the vibration of power device (1) and the non-complete coaxial installation position of power device (1) and electrode bushing (201), so that electrode bushing (201) is more stable while rotating, the control assembly (8) is used to control the rotating speed of power device (1).

2. A dynamic disc electrode coater according to claim 1, wherein: It also includes shell body (3), the power device (1) is installed inside the shell body (3).

3. A dynamic disc electrode coater according to claim 2, wherein: The rotating base (2) further includes bearing seat (202), the bearing seat (202) is installed on the shell body (3), the bearing (203) is installed in the bearing seat (202), and the electrode bushing (201) is installed inside the bearing (203).

4. A dynamic disc electrode coater according to claim 3, wherein: The bearing (203) has two groups, which are installed in the bearing seat (202) in the axial direction, and the electrode bushing (201) is supported by the two groups of bearings (203) to ensure the coaxiality of the electrode bushing (201) when rotating, effectively improving the stability of the electrode bushing (201) when rotating.

5. A dynamic disc electrode coater according to claim 4, wherein: The transmission chassis (6) and the electrode bushing (201) are connected by interference fit.

6. A dynamic disc electrode coater according to claim 5, wherein: A plurality of counterbores are arranged at the bottom of the electrode bushing (201), and a plurality of bosses corresponding to the counterbores are arranged on the transmission chassis (6).

7. A dynamic disc electrode coater according to claim 6, wherein: The transmission chassis (6) and the electrode bushing (201) are an integral structure.

8. A dynamic disc electrode coater according to claim 1, wherein: The electrode bushing (201) is made of plastic material, which can effectively avoid the experimental influence of contact pollution on disc electrode.

9. A dynamic disc electrode coater according to claim 1, wherein: The electrode bushing (201) is made of PTFE polytetrafluoroethylene material.

10. A dynamic disc electrode coater according to claim 1, wherein: A limiting shoulder for limiting and clamping disc electrode is arranged on the upper surface of the transmission chassis (6).

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