System and method for testing the mass activity of oxygen reduction catalysts

Abstract

The present invention discloses a mass activity testing system and method for oxygen reduction catalysts. The mass activity testing system of the present invention comprises an open circuit voltage measuring module and a mass activity data output module connected in sequence; the open circuit voltage measuring module is used to measure the open circuit voltage of the oxygen reduction catalyst to be tested; the mass activity data output module is used to output the mass activity data of the oxygen reduction catalyst to be tested; wherein the mass activity data output module comprises a mass activity data converter, which is used to convert the mass activity data according to the relationship I fitted with the open circuit voltage of several oxygen reduction catalysts with the same mass content percentage of the active component as the horizontal coordinate and the mass activity of several said oxygen reduction catalysts as the vertical coordinate. The mass activity testing system of the oxygen reduction catalyst of the present invention can obtain the mass activity data of the oxygen reduction catalyst simply and quickly.

Description

Technical Field

[0001] The invention relates to a mass activity testing system and method for an oxygen reduction catalyst. Background Art

[0002] As an energy conversion device, proton exchange membrane fuel cells have the characteristics of high conversion efficiency, high power density, clean and pollution-free, and are a form of energy utilization with great development potential. However, the cathode oxygen reduction reaction of proton exchange membrane fuel cells involves the transfer of multiple protons and electrons, and its cathode kinetics are 6 orders of magnitude different from the anode reaction. The slow kinetic process seriously hinders the development of the commercialization of proton exchange membrane fuel cells. In order to address this problem, it is key to design and develop oxygen reduction catalysts with long service life and high catalytic activity. Among them, mass activity has been widely concerned as the core indicator for evaluating oxygen reduction catalysts.

[0003] In order to determine and evaluate the electrocatalytic activity of catalysts, there are usually two key indicators: mass activity and specific activity. Among them, mass activity is obtained by normalizing the current density to the precious metal loading mass of the electrocatalyst, and can be used as a reasonable parameter to evaluate the intrinsic performance of different electrocatalytic materials in reaction processes such as oxygen reduction reaction. Mass activity depends largely on the number of active sites on the electrocatalyst particles. Among them, specific activity is estimated by normalizing the current density to the surface area of ​​the electrocatalyst. Since the surface area is associated with the number of surface atoms, and the number of surface atoms can represent the actual number of active sites, the specific activity can reflect the intrinsic activity of the catalyst.

[0004] The mass activity at the corresponding potential (such as 0.9V, 0.85V, etc.) is often used as the electrochemical activity of the test catalyst. For Pt-based catalysts, the electrochemical activity area (ECSA), specific activity (SA), and mass activity (MA) are generally used to evaluate the performance of the catalyst.

[0005]

[0006] Where Q is the adsorption charge of hydrogen; m is the mass of Pt on the working electrode, S is the integral area of ​​the hydrogen desorption zone in the cyclic voltammetry curve; v is the test scan speed; and 210 is a constant.

[0007] The kinetic current density j was calculated according to the Koutecky-Levich equation k .

[0008]

[0009] Where j is the experimentally measured current density and jL is the limiting diffusion current density.

[0010] The calculation formula for specific activity is:

[0011]

[0012] The calculation formula of mass activity is:

[0013]

[0014] Here m refers to the Pt loading on the working electrode.

[0015] For the above determination methods, it is necessary to go through a complex and lengthy data processing process to obtain mass activity information. This situation needs to be solved urgently. Summary of the invention

[0016] The purpose of the present invention is to solve the technical problems in the prior art such as the need to determine the mass activity of the catalyst through a complex and lengthy data processing process, and to provide a new mass activity test system and method for oxygen reduction catalysts. The method of the present invention is applicable to various electrochemical reactions involving the field of electrocatalysis, with high accuracy, simplicity and speed.

[0017] In the current prior art electrochemical and electrocatalytic tests, the mass activity of oxygen reduction catalysts can often only be determined after a complex and tedious data processing process, which consumes a lot of energy and time. The inventors found through the study of a large amount of experimental data that there is a one-to-one correspondence between open circuit voltage and mass activity. Catalysts with high mass activity have higher open circuit voltages, and vice versa. Therefore, the inventors thought of associating the two electrochemical performance parameters to save time and simplify the process of obtaining the mass activity of oxygen reduction catalysts. No researchers have yet proposed a relationship between open circuit voltage and catalyst mass activity.

[0018] The inventors found that the relative error of the mass activity obtained by the method of the present invention is between 0-16.2%, and its reliability and accuracy are very high. Those skilled in the art know that within this field, the relative error within 16.2% belongs to the range of high accuracy. The inventors believe that it is of great significance to test and predict the electrocatalytic activity of the catalyst based on the existing electrochemical data open circuit voltage. By measuring the different open circuit voltages of the catalyst, the mass activity of the catalyst can be determined, and it will help researchers to conduct further research. For example, the method of the present invention is used to predict and judge the catalytic activity of the oxygen reduction catalyst, which is convenient for rapid screening of high-activity catalysts, and is conducive to the subsequent assembly of the catalyst into a single fuel cell for further performance testing.

[0019] The present invention provides a mass activity testing system for an oxygen reduction catalyst, which comprises an open circuit voltage measurement module and a mass activity data output module connected in sequence;

[0020] The open circuit voltage measurement module is used to measure the open circuit voltage of the oxygen reduction catalyst to be tested;

[0021] The mass activity data output module is used to output the mass activity data of the oxygen reduction catalyst to be tested; wherein the mass activity data output module includes a mass activity data converter, which is used to convert the mass activity data according to a relationship I in which the open circuit voltages of several oxygen reduction catalysts with the same mass content percentage of the active components are used as the horizontal coordinate and the mass activities of several oxygen reduction catalysts are used as the vertical coordinate; the mass content of the active components of the oxygen reduction catalyst to be tested is equal to the mass content of the active components of the oxygen reduction catalyst fitted in the relationship I.

[0022] Those skilled in the art know that the mass content of the active component of the oxygen reduction catalyst refers to the ratio of the mass of the active component to the total mass of the oxygen reduction catalyst.

[0023] In the present invention, the open circuit voltage measurement module is a device commonly used in the art that can measure the open circuit voltage of an oxygen reduction catalyst, such as a three-electrode system and an electrochemical workstation.

[0024] Among them, those skilled in the art know that the three-electrode system generally includes: a glassy carbon electrode as a working electrode, a carbon rod as a counter electrode, a saturated calomel electrode as a reference electrode, and an electrolyte solution is a perchloric acid aqueous solution; wherein the oxygen reduction catalyst to be tested forms a film on the working electrode, preferably on the glassy carbon electrode; wherein the concentration of the perchloric acid aqueous solution is preferably 0.1 mol / L. wherein the pH of the perchloric acid aqueous solution is preferably 1.

[0025] The working electrode is preferably a rotating disk electrode. Those skilled in the art know that the rotating disk electrode refers to a high-speed rotating electrode developed by electrochemical researchers by comparing various electrodes and stirring methods in order to study the distribution of current density on the electrode surface and reduce or eliminate the influence of factors such as the diffusion layer. The end surface of the rotating disk electrode is like a disk.

[0026] Among them, those skilled in the art know that the film-forming material is generally a catalyst slurry containing the oxygen reduction catalyst to be tested. The catalyst slurry generally also includes a Nafion solution and a solvent. The Nafion solution refers to a perfluorosulfonic acid-polytetrafluoroethylene copolymer solution, and the mass concentration of the Nafion solution can be 2 to 20wt%, for example, 5wt% or 20wt%. The Nafion solution can be obtained through market sales. In the commercially available Nafion solution, when the mass concentration of the Nafion solution is 5%, its water content is generally 45%; when the mass concentration of the Nafion solution is 20%, its water content is generally 34%. wt% refers to the mass percentage of Nafion in the Nafion solution. The solvent can be conventional in the art, such as isopropanol and / or ethanol. The state of the catalyst slurry is preferably a dispersed state, and more preferably a uniformly dispersed state. The method of obtaining the dispersed state is preferably to use ultrasonic ultrasound.

[0027] The electrochemical workstation may be a conventional electrochemical workstation in the art, such as a Coster CS350 electrochemical workstation.

[0028] Generally speaking, when measuring, the open circuit voltage measurement module starts the three-electrode system and the electrochemical workstation, obtains the LSV data graph through linear voltammetry scanning, and the potential corresponding to when the current in the circuit is equal to 0 is the open circuit voltage of the oxygen reduction catalyst.

[0029] In the present invention, the oxygen reduction catalyst is preferably a platinum-based catalyst, such as one or more of a platinum black catalyst, a platinum carbon catalyst, a platinum manganese catalyst, a platinum cobalt catalyst, a platinum nickel catalyst, a platinum iron catalyst and a platinum copper catalyst; the mass content of platinum in the platinum-based catalyst may be 5% to 20%, preferably 20%. The mass content refers to the mass percentage of platinum in the platinum-based catalyst. Those skilled in the art know that the platinum-based catalyst refers to a catalyst with metallic platinum as the main active component.

[0030] In the present invention, those skilled in the art know that the oxygen reduction catalyst in the fitted relational expression I and the active component in the oxygen reduction catalyst to be tested generally have to be consistent, and different carriers do not affect the test results.

[0031] In the present invention, the mass activity data output module may be in the form of a control chip integrated with mass activity data conversion and output functions. The mass activity data may be obtained by normalizing the current density of the original electrochemical data to the loading mass of the oxygen reduction catalyst.

[0032] In the present invention, the relationship I is preferably:

[0033] y=-13759603.0871582x 6 +77703708.5486298x 5 -182786413.3913150x 4 +

[0034] 229257705.0786690x 3 -161698916.8358540x 2 +60809441.7592292x-9525921.7557577;

[0035] Wherein x is the open circuit voltage of the platinum-based catalyst, y is the mass activity of the platinum-based catalyst; the mass content of platinum in the platinum-based catalyst is 20%.

[0036] In the present invention, the relational expression I is preferably obtained by data fitting. The fitting method may be conventional in the art, generally using polynomial fitting to obtain a related polynomial relationship. The polynomial fitting method may be conventional in the art, generally using Origin software for fitting. The data for data fitting is generally multiple sets of data, at least seven sets of data, for example, 11 sets of data. The multiple sets of data may be drawn in the form of a scatter plot. Those skilled in the art know that the more data, the better.

[0037] In the present invention, the relationship I can be expressed by a relationship curve or a table.

[0038] In the present invention, the open circuit voltage is preferably in the range of 0.85-1.1V; for example, 0.9, 0.907, 0.91, 0.917, 0.92, 0.946, 0.964, 0.969, 0.97, 0.99 or 0.995V.

[0039] In the present invention, the mass activity is preferably in the range of 0.002-0.4 A·mg -1 pt ; for example, 0.004, 0.020, 0.013, 0.0035, 0.035, 0.084, 0.087, 0.120, 0.290 or 0.320 A·mg -1 pt . The A·mg -1 pt It refers to the amount of current generated per milligram of platinum.

[0040] The present invention provides a method for testing the mass activity of an oxygen reduction catalyst, which comprises the following steps:

[0041] S1. Prepare the following formula: Relationship formula I with the open circuit voltage of a number of oxygen reduction catalysts as the abscissa and the mass activity of a number of oxygen reduction catalysts as the ordinate,

[0042] S2. Measure the open circuit voltage of the oxygen reduction catalyst to be tested, substitute it into the relational equation I in step S1, and obtain the mass activity data of the oxygen reduction catalyst to be tested. The mass content of the active component of the oxygen reduction catalyst to be tested is equal to the mass content of the active component of the oxygen reduction catalyst fitted in the relational equation I.

[0043] In step S1, the open circuit voltage can be obtained by an electrochemical testing method. The electrochemical testing method can be conventional in the art, generally comprising the following steps:

[0044] (1) forming a film by covering a catalyst slurry containing the oxygen reduction catalyst to be tested on a working electrode;

[0045] (2) performing cyclic voltammetry scanning to remove organic matter on the catalyst surface and activate the catalyst, and introducing oxygen;

[0046] (3) Performing a linear voltammetric scan to obtain an LSV data graph, wherein the potential corresponding to when the current in the circuit is equal to 0 is the open circuit voltage of the oxygen reduction catalyst to be tested.

[0047] The oxygen flow rate is preferably 80 mL / min, and the oxygen introduction time is preferably 30 min.

[0048] The mass activity test method of the oxygen reduction catalyst to be tested is to use the mass activity test system as described above to obtain the mass activity result of the oxygen reduction catalyst to be tested.

[0049] The positive and progressive effects of the present invention are:

[0050] 1. The mass activity testing system of the oxygen reduction catalyst of the present invention has simple equipment and strong operability, and can obtain the mass activity data of the oxygen reduction catalyst simply and quickly.

[0051] 2. The mass activity test method of the oxygen reduction catalyst of the present invention has high accuracy, with a relative error of 0-16.2%. It is simple and quick, and does not require a complex and lengthy data processing process to determine the mass activity of the catalyst. It is suitable for various electrochemical reactions involving the field of electrocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a scatter plot of open circuit voltage-mass activity data for Example 1.

[0053] Figure 2 This is a polynomial fitting curve diagram of the open circuit voltage-mass activity data of Example 1.

[0054] Figure 3 This is the linear sweep voltammetry curve of Example 1.

[0055] Figure 4 This is the linear sweep voltammetry curve of Example 2.

[0056] Figure 5 This is the linear sweep voltammetry curve of Example 3.

[0057] Figure 6 This is the linear sweep voltammetry curve of Example 4.

[0058] Figure 7 This is the linear sweep voltammetry curve of Example 5. DETAILED DESCRIPTION

[0059] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0060] Example 1

[0061] A mass activity testing system for an oxygen reduction catalyst, comprising an open circuit voltage measurement module and a mass activity data output module connected in sequence;

[0062] An open circuit voltage measurement module, used to measure the open circuit voltage of the oxygen reduction catalyst to be tested;

[0063] A mass activity data output module is used to output the mass activity data of the oxygen reduction catalyst to be tested; wherein the mass activity data output module includes a mass activity data converter, which is used to convert the mass activity data according to a relationship I in which the open circuit voltages of several oxygen reduction catalysts with the same mass content percentage of the active components are used as the horizontal coordinate and the mass activities of several oxygen reduction catalysts are used as the vertical coordinate; the mass content of the active components of the oxygen reduction catalyst to be tested is equal to the mass content of the active components of the oxygen reduction catalyst fitted in the relationship I.

[0064] The open circuit voltage measurement module is a three-electrode system and a Coster CS350 electrochemical workstation. The three-electrode system includes: a glassy carbon electrode as a working electrode, a carbon rod as a counter electrode, a saturated calomel electrode as a reference electrode, and an electrolyte solution of perchloric acid aqueous solution with a pH of 1; wherein the oxygen reduction catalyst forms a film on the glassy carbon electrode. Among them, the working electrode is a rotating disk electrode.

[0065] The film-forming material is a catalyst slurry containing an oxygen reduction catalyst to be tested, and the catalyst slurry also includes a Nafion solution and a solvent. The Nafion solution refers to a perfluorosulfonic acid-polytetrafluoroethylene copolymer solution, and the concentration of the Nafion solution is 5%. wt% refers to the mass percentage of Nafion in the Nafion solution. The solvent is isopropanol. The state of the catalyst slurry is a uniformly dispersed state.

[0066] The oxygen reduction catalyst is a platinum-based catalyst with a mass content of 20%. The mass content refers to the mass percentage of platinum in the platinum-based catalyst.

[0067] The mass active data output module is in the form of a control chip that integrates mass active data conversion and output functions.

[0068] A method for testing the mass activity of an oxygen reduction catalyst comprises the following steps:

[0069] S1. Formula: The open circuit voltage of the sample oxygen reduction catalyst in the following 11 is taken as the horizontal coordinate and the mass activity thereof is taken as the vertical coordinate. Relationship formula I:

[0070] S11, using an open circuit voltage measurement module to obtain the open circuit voltage data of the following 11 sample oxygen reduction catalysts, specifically:

[0071] (1) 5 mg of platinum-based catalyst, 40 μL of 5% Nafion solution, and 960 μL of isopropanol were mixed to prepare a catalyst slurry, and ultrasonicated for 2 h until it was uniformly dispersed and used for later use;

[0072] (2) Electrochemical testing using an electrochemical workstation and a rotating disk electrode: The electrochemical test was performed in a three-electrode test system. Argon was introduced into the electrolyte solution, and the argon flow rate was controlled at 80 mL / min using a mass flow meter. The solution was ventilated for 30 min until saturation.

[0073] (3) Use a micropipette to transfer 4 μL of the above catalyst slurry dispersion solution onto the platinum carbon electrode to form a uniform film, connect the three-electrode system to the electrochemical workstation, and perform cyclic voltammetry scanning to remove organic matter on the catalyst surface and activate the catalyst; then introduce oxygen into the electrolyte solution, use a mass flow meter to control the oxygen flow rate to 80 mL / min, and ventilate for 30 min until saturation.

[0074] (4) Connect the three-electrode system to the electrochemical workstation, turn on the rotating disk, and perform a linear voltammetric scan at a speed of 1600 rpm / min to obtain the LSV data as shown in the figure. Figure 3 As shown, the oxygen flow rate was maintained at 80 mL / min during the test, and the potential corresponding to when the current in the circuit was equal to 0 was read from the LSV data graph. This potential is the open circuit voltage of the catalyst.

[0075] S12, obtaining the mass activity data of the oxygen reduction catalyst of the sample in 11: normalizing the current density of the original electrochemical data to the loading mass of the electrocatalyst to obtain the mass activity data; the calculation steps of the mass activity data are as follows:

[0076]

[0077]

[0078]

[0079]

[0080] Where Q is the adsorption charge of hydrogen; m is the mass of Pt on the working electrode, S is the integral area of ​​the hydrogen desorption zone in the cyclic voltammetry curve; v is the test scan speed; and 210 is a constant.

[0081] The current density at 0.5 V and the current density at 0.9 V were read from the linear sweep voltammetry curve as jL and j, respectively, and substituted into the above formula to obtain the electrochemical mass activity.

[0082] The open circuit voltage and mass activity data of 11 samples were measured according to the above steps, as shown in Table 1 below.

[0083] Among them, the catalyst types and sources of the 11 samples are as follows:

[0084] Sample 1 PtPb catalyst, synthesized by acetone liquid phase reduction method, with a Pt content of 20%;

[0085] Sample 2 PtPb catalyst was synthesized by acetone liquid phase reduction method, and its Pt content was 20%;

[0086] Sample 3 PtCu catalyst was synthesized by acetone liquid phase reduction method, and its Pt content was 20%;

[0087] Sample 4 PtC catalyst was synthesized by freeze drying in aqueous phase, and its Pt content was 20%;

[0088] Sample 5 PtCu catalyst was synthesized by acetone liquid phase reduction method, and its Pt content was 20%;

[0089] Sample 6 PtNi catalyst was synthesized by acetone liquid phase reduction method, and its Pt content was 20%;

[0090] Sample 7 PtC catalyst, commercial PtC purchased on the market, with a Pt content of 20%;

[0091] Sample 8 PtC catalyst, commercial PtC purchased on the market, with a Pt content of 20%;

[0092] Sample 9 PtFe catalyst was synthesized by freeze drying in water phase, and its Pt content was 20%;

[0093] Sample 10 PtCo catalyst was synthesized by freeze drying in water phase, and its Pt content was 20%;

[0094] Sample 10 PtNi catalyst was synthesized by freeze-drying in water phase, and its Pt content was 20%.

[0095] Table 1. Sample open circuit voltage-mass activity data table

[0096] Sample No. 1 2 3 4 5 6 Open circuit voltage / V 0.9 0.907 0.91 0.917 0.92 0.946 <![CDATA[Mass activity / A·mg -1 pt > 0.004 0.020 0.004 0.013 0.0035 0.035 Sample No. 7 8 9 10 11 Open circuit voltage / V 0.964 0.969 0.97 0.99 0.995 <![CDATA[Mass activity / A·mg -1 pt > 0.084 0.087 0.120 0.290 0.320

[0097] S13, using a mass activity data converter of the mass activity data output module, performing mass activity data conversion according to the relationship I in which the open circuit voltage of the oxygen reduction catalyst of the above 11 samples is the horizontal coordinate and the mass activity data thereof is the vertical coordinate. Specifically:

[0098] a. Draw a scatter plot of the above 11 sets of open circuit voltage-mass activity scatter data as shown in Figure 1 shown.

[0099] b. Use Origin to perform polynomial fitting, which specifically involves importing the above data points into the Origin data processing software to form a table, plotting, and mathematically analyzing to perform polynomial fitting. The resulting polynomial relationship equation I is shown below, and the required working curve is obtained as Figure 2 shown.

[0100] Relation I:

[0101] y=-13759603.0871582x 6 +77703708.5486298x 5 -182786413.3913150x 4 +229257705.0786690x 3 -161698916.8358540x 2 +60809441.7592292x-9525921.7557577.

[0102] Where x is the open circuit voltage of the platinum-based catalyst; y is the mass activity of the catalyst.

[0103] S2. Measure the open circuit voltage of the PtNi catalyst synthesized by the impregnation calcination method (wherein the mass content of the platinum base is 20%, and the catalyst is a self-synthesized catalyst). The open circuit voltage is 0.983 V. Substituting it into the relational equation I in step S1, the mass activity data of the catalyst is obtained to be 0.206 A·mg -1 pt .

[0104] Example 2

[0105] The mass activity test system of the oxygen reduction catalyst in Example 1 was used.

[0106] The test method for the mass activity of the oxygen reduction catalyst is:

[0107] S1. Using the same step S1 as in Example 1, obtain relational expression I.

[0108] S2. The open circuit voltage of the PtNi alloy catalyst (the mass content of the platinum base is 20%, and the catalyst is a self-synthesized catalyst) for carbon monoxide assisted reduction is 0.941 V. Its LSV is as follows: Figure 4 As shown; Substituting the open circuit voltage value into the relational formula I, the mass activity data of the catalyst is 0.037A·mg -1 pt .

[0109] Example 3

[0110] The mass activity test system of the oxygen reduction catalyst in Example 1 was used.

[0111] The test method for the mass activity of the oxygen reduction catalyst is:

[0112] S1. Using the same step S1 as in Example 1, obtain relational expression I.

[0113] S2. Measure the open circuit voltage of a commercial PtC sample (the mass content of the platinum base is 20%, and the commercial PtC catalyst purchased on the market). Figure 5 Substituting the open circuit voltage value into the relational equation I of Example 1, the mass activity data of the catalyst is obtained to be 0.097A·mg - 1

[0114] p t .

[0115] Example 4

[0116] The mass activity test system of the oxygen reduction catalyst in Example 1 was used.

[0117] The test method for the mass activity of the oxygen reduction catalyst is:

[0118] S1. Using the same step S1 as in Example 1, obtain relational expression I.

[0119] S2. The open circuit voltage of the PtCo catalyst (the mass content of the platinum base is 20%, and the catalyst is synthesized independently) prepared by liquid phase impregnation-freeze drying-calcination is measured to be 0.985V. Its LSV is as follows Figure 6 Substituting the open circuit voltage value into the relational equation I of Example 1, the mass activity data of the catalyst is obtained to be 0.273A·mg -1 pt .

[0120] Example 5

[0121] The mass activity test system of the oxygen reduction catalyst in Example 1 was used.

[0122] The test method for the mass activity of the oxygen reduction catalyst is:

[0123] S1. Using the same step S1 as in Example 1, obtain relational expression I.

[0124] S2. The open circuit voltage of the PtNi catalyst (the mass content of the platinum base is 20%, and the catalyst is independently synthesized) synthesized by ethylene glycol-assisted reduction is measured to be 0.996 V. Its LSV is as follows Figure 7 As shown; Substituting the open circuit voltage value into the relational formula I, the mass activity data of the catalyst is 0.323A·mg -1 pt .

[0125] Effect Example 1

[0126] The experimental measured values ​​and predicted values ​​of the oxygen reduction catalysts to be tested in Examples 1-5 are compared, and the specific results are shown in the data in Table 2. Among them, the method for obtaining the measured values ​​of the mass activity of the oxygen reduction catalysts to be tested in Examples 1-5 is consistent with the method for calculating the mass activity data in step S12 in Example 1.

[0127] Table 2 Open circuit voltage-mass activity data of samples in the embodiment

[0128]

[0129]

[0130] From the data in the above table, it can be seen that the mass activity of the catalyst predicted by the fitted polynomial relationship is highly consistent with the experimental measured results, and the relative error is between 0-16.2%, which shows that the present invention has high practical value and strong applicability. This method can also be applied to other electrocatalytic fields.

[0131] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope of the present invention as defined in the claims.

Claims

1. A mass activity test system for an oxygen reduction catalyst, characterized in that: It includes an open circuit voltage measurement module and a mass activity data output module connected in sequence; The open circuit voltage measurement module is used to measure the open circuit voltage of the oxygen reduction catalyst to be tested; The mass activity data output module is used to output the mass activity data of the oxygen reduction catalyst to be tested; wherein the mass activity data output module includes a mass activity data converter, which is used to convert the mass activity data according to a fitted relational expression I in which the open circuit voltages of several oxygen reduction catalysts with the same mass content percentage of active components are used as the horizontal coordinates and the mass activities of several oxygen reduction catalysts are used as the vertical coordinates; the mass content of the active components of the oxygen reduction catalyst to be tested is equal to the mass content of the active components of the oxygen reduction catalyst in the fitted relational expression I; The oxygen reduction catalyst is a platinum-based catalyst; The relational formula I is: <h2 style=";text-align:left;direction:ltr">y=-13759603.0871582x<h2 style=";text-align:left;direction:ltr"> 6 <h2 style=";text-align:left;direction:ltr"> +77703708.5486298x<h2 style=";text-align:left;direction:ltr"> 5 <h2 style=";text-align:left;direction:ltr"> -182786413.3913150x<h2 style=";text-align:left;direction:ltr"> 4 <h2 style=";text-align:left;direction:ltr"> +229257705.0786690x<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> -161698916.8358540x<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +60809441.7592292x-9525921.7557577; Wherein x is the open circuit voltage of the platinum-based catalyst, y is the mass activity of the platinum-based catalyst; the mass content of platinum in the platinum-based catalyst is 20%.

2. The mass activity test system of the oxygen reduction catalyst according to claim 1, characterized in that: The open circuit voltage measurement module comprises a three-electrode system and an electrochemical workstation.

3. The mass activity test system of the oxygen reduction catalyst according to claim 2, characterized in that: The three-electrode system comprises: a glassy carbon electrode as a working electrode, a carbon rod as a counter electrode, a saturated calomel electrode as a reference electrode, and an electrolyte solution of perchloric acid aqueous solution; the oxygen reduction catalyst to be tested forms a film on the working electrode; And / or, the electrochemical workstation is a Coster CS350 electrochemical workstation.

4. The mass activity testing system of the oxygen reduction catalyst according to claim 3, characterized in that: The concentration of the perchloric acid aqueous solution is 0.1 mol / L; And / or, the working electrode is a rotating disk electrode; and / or, the film-forming material is a catalyst slurry containing the oxygen reduction catalyst to be tested.

5. The mass activity testing system for oxygen reduction catalyst according to claim 4, characterized in that: The catalyst slurry also includes a Nafion solution and a solvent.

6. The mass activity testing system for oxygen reduction catalyst according to claim 2, characterized in that: When measuring, the open circuit voltage measurement module starts the three-electrode system and the electrochemical workstation, obtains the LSV data diagram through linear voltammetry scanning, and the potential corresponding to when the current in the circuit is equal to 0 is the open circuit voltage of the oxygen reduction catalyst.

7. The mass activity test system of the oxygen reduction catalyst according to claim 1, characterized in that: The oxygen reduction catalyst is one or more of a platinum black catalyst, a platinum carbon catalyst, a platinum manganese catalyst, a platinum cobalt catalyst, a platinum nickel catalyst, a platinum iron catalyst and a platinum copper catalyst.

8. The mass activity testing system for oxygen reduction catalyst according to claim 1, characterized in that: The mass activity data output module is in the form of a control chip that integrates mass activity data conversion and output functions.

9. The mass activity testing system for oxygen reduction catalyst according to claim 8, characterized in that: The mass activity data are obtained by normalizing the current density of the raw electrochemical data to the loaded mass of the oxygen reduction catalyst.

10. The mass activity testing system of the oxygen reduction catalyst according to claim 1, characterized in that: The relational formula I is obtained by data fitting; And / or, the relationship I is represented by a relationship curve or a table; And / or, the open circuit voltage ranges from 0.85V to 1.1V And / or, the mass activity range is 0.002-0.4 A·mg -1 pt .

11. The mass activity testing system of the oxygen reduction catalyst according to claim 10, characterized in that: The fitting method is to use polynomial fitting to obtain the relevant polynomial relationship; and / or, the open circuit voltage is in the range of 0.9, 0.907, 0.91, 0.917, 0.92, 0.946, 0.964, 0.969, 0.97, 0.99 or 0.995 V; And / or, the mass activity range is 0.004, 0.020, 0.013, 0.0035, 0.035, 0.084, 0.087, 0.120, 0.290 or 0.320 A·mg -1 pt .

12. A method for testing the mass activity of an oxygen reduction catalyst, comprising the following steps: S1. Prepare the following formula: Relationship formula I with the open circuit voltage of a number of oxygen reduction catalysts as the abscissa and the mass activity of a number of oxygen reduction catalysts as the ordinate, S2, measuring the open circuit voltage of the oxygen reduction catalyst to be measured, substituting it into the relational equation I in step S1, and obtaining the mass activity data of the oxygen reduction catalyst to be measured, wherein the mass content of the active component of the oxygen reduction catalyst to be measured is equal to the mass content of the active component of the oxygen reduction catalyst in the fitted relational equation I; The open circuit voltage is obtained by an electrochemical testing method; Wherein, the electrochemical testing method comprises the following steps: (1) coating a catalyst slurry containing the oxygen reduction catalyst to be tested on a working electrode to form a film; (2) Perform cyclic voltammetry to remove organic matter on the catalyst surface and activate the catalyst, and introduce oxygen; (3) performing a linear voltammetric scan to obtain an LSV data graph, wherein the potential corresponding to when the current in the circuit is equal to 0 is the open circuit voltage of the oxygen reduction catalyst to be tested; The mass activity testing method of the oxygen reduction catalyst to be tested is to use the mass activity testing system as described in any one of claims 1 to 8 to obtain the mass activity result of the oxygen reduction catalyst to be tested.

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