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GB/T 20042.4-2025 English PDF

GB/T 20042.4: Historical versions

Standard IDUSDBUY PDFLead-DaysStandard Title (Description)Status
GB/T 20042.4-2025RFQ ASK 3 days Proton exchange membrane fuel cell - Part 4: Test method for electrocatalysts Valid
GB/T 20042.4-2009255 Add to Cart Auto, < 3 mins Proton exchange membrane fuel cell - Part 4: Test method for electrocatalysts Valid


Basic data

Standard ID: GB/T 20042.4-2025 (GB/T20042.4-2025)
Description (Translated English): Proton exchange membrane fuel cell - Part 4: Test method for electrocatalysts
Sector / Industry: National Standard (Recommended)
Date of Implementation: 2026-03-01
Older Standard (superseded by this standard): GB/T 20042.4-2009

GB/T 20042.4-2009: Proton exchange membrane fuel cell - Part 4: Test method for electrocatalysts

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Proton exchange membrane fuel cell.Part 4. Test method for electrocatalysts ICS 27.070 K82 National Standards of People's Republic of China Proton exchange membrane fuel cell Part 4. Electrocatalyst test methods Published on.2009-04-21 2009-11-01 Implementation General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China China National Standardization Administration released

Foreword

GB/T 20042 "Proton Exchange Membrane Fuel Cell" is divided into six parts. --- Part 1. Terminology; --- Part 2. General technical conditions for battery stacks; --- Part 3. Proton exchange membrane test methods; --- Part 4. Electrocatalyst test methods; --- Part 5. Membrane electrode test methods; --- Part 6 . Test methods for bipolar plates . This part is part 4 of GB/T 20042. Appendix A of this section is an informative appendix. This part is proposed by the China Electrical Appliance Industry Association. This part is under the jurisdiction of the National Fuel Cell Standardization Technical Committee (SAC/TC342). This part is responsible for drafting. Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Participated in the drafting of this section. Beijing Institute of Mechanical and Electrical Technology, Mechanical Industry. The main drafters of this section. Zhong Hexiang, Zhang Huamin, Qiu Yanling, Lu Hao, Wang Meiri, Yi Baolian. This section is for the first time. Proton exchange membrane fuel cell Part 4. Electrocatalyst test methods

1 Scope

This part of GB/T 20042 specifies the terms and definitions of the test method for proton exchange membrane fuel cell electrocatalysts, platinum content test, Electrochemical active area test, specific surface area, pore volume, pore size distribution test, morphology and particle size distribution test, crystal structure test, catalyst stacking Degree test and cell polarization curve test. This section applies to various types of proton exchange membrane fuel cell platinum-based (Pt-based) electrocatalyst.

2 Normative references

The terms in the following documents have been adopted as references in this part of GB/T 20042 as the terms of this part. Any quoted text Any subsequent amendments (not including errata content) or revisions do not apply to this section, however, it is encouraged to achieve The parties to the agreement study whether the latest versions of these documents can be used. For undated references, the latest edition applies to this section. GB/T 5816-1995 Catalyst and adsorbent surface area method GB/T 13566-1992 Fertilizer bulk density determination method (ISO 3944.1980, EQV) GB/T 15072.7-2008 Methods for chemical analysis of precious metal alloys Determination of chromium and iron content in gold alloys Inductively-coupled plasmas Bulk atomic emission spectrometry GB/T 20042.1 Proton Exchange Membrane Fuel Cell Terminology

3 Terms and Definitions

The following terms and definitions established in GB/T 20042.1 apply to this section. The effective activity specific surface area of the catalyst, measured in electrochemical methods, is m2/g. Note. Indicates how many active sites the catalyst participates in electrochemical reactions.

4 platinum content test

4.1 Thermogravimetric Test for Platinum Content 4.1.1 Application This method is only applicable to the Pt content of Pt/C catalyst with Pt loading higher than 20%. 4.1.2 Using the Instrument Thermogravimetric analyzer (TGA). 4.1.3 Sample preparation 4.1.3.1 Weigh the appropriate amount of catalyst sample, the quality should meet the requirements of 3 effective tests. 4.1.3.2 The test sample shall be dried in a vacuum oven at 80°C for 12 hours. 4.1.4 Test Process 4.1.4.1 Weigh the appropriate amount of sample into the test enthalpy of the thermogravimetric analyzer and weigh it by air or air and inert gas. The composition of the mixture as a working gas, control gas flow rate of 50mL/min, the sample from the room temperature program to the end temperature of 800 °C, The heating rate is 2°C/min. Note. The gas flow rate, heating rate, and end temperature of the test can also be determined by the sample submitter and the tester, depending on the nature of the catalyst. 4.1.4.2 After a constant weight of the sample, record the temperature-weight curve of the sample. 4.1.5 Data Processing Calculate Pt loading according to formula (1). L=W1/W0×100% (1) In the formula. L---Pt load, unit is %; W1 - the mass of the endpoint temperature sample in milligrams (mg); W0---The original mass of the sample in milligrams (mg). Take 3 samples as a group and calculate the average as the test result. Refer to GB/T 15072.7-2008 for testing. 4.2.1 Application This method is applicable to the Pt content test of Pt/C catalyst and Pt alloy catalyst. 4.2.2 Test Instruments and Equipment 4.2.2.1 Ion-coupled emission spectrometry (ICP). The minimum detection limit is ≤1 μg/L. 4.2.2.2 Analytical balance. The accuracy is 0.1mg. 4.2.2.3 Caliper. The measurement accuracy is 0.01mm. 4.2.3 Sample preparation The sample quality is not less than 2g. The sample was placed in a vacuum oven and dried at 80[deg.] C. for 12 h. 4.2.4 Reagents and Materials 4.2.4.1 concentrated sulfuric acid (98%), superior grade pure. 4.2.4.2 Concentrated hydrochloric acid (37%), pure grade. 4.2.4.3 concentrated nitric acid (68%), superior grade pure. 4.2.4.4 Secondary distilled water, resistivity ≥ 18.2 MΩ·cm. 4.2.4.5 30% hydrogen peroxide, analytical grade. 4.2.4.6 Covered corundum. 4.2.5 Test Method 4.2.5.1 Sample oxidation ashing. Place the lidded crucible with the sample into the muffle furnace and oxidize it in an atmosphere of air at 400°C to 500°C. After carbonization for 6 hours, the temperature was increased to 900 DEG C. to 950 DEG C. for ashing for 12 hours and then cooled to room temperature. 4.2.5.2 Nitration of the sample. Place the sample in a lidded corundum and moisten with distilled water. Then slowly add to the sample along the wall 6mL ~ 12mL concentrated sulfuric acid and concentrated nitric acid mixture. Among them, the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 1.3. Heat the sample at 80 °C When the acid volume is concentrated to one-half, add an appropriate amount of concentrated sulfuric acid and concentrated nitric acid and 0.2 mL to 0.3 mL of 30% hydrogen peroxide solution. The nitration was continued by heating to 80°C, and the cycle was repeated until the solution was nearly transparent and there was no suspended matter. 4.2.5.3 The sample dissolves. After the sample is fully nitrated, add a suitable amount of freshly prepared aqua regia along the wall and heat it at 80°C until the sample solution is completely Clear and transparent so far. 4.2.5.4 Preparation of test samples. Transfer the above sample to the appropriate volumetric flask and use distilled water as the test sample. The initial volume, the appropriate amount of this solution is diluted to the concentration required for the test by a certain proportion. 4.2.6 Drawing of Standard Curve Spectroscopic analysis of Pt standard solution and alloy metal M standard solution in alloy catalyst using ICP to plot Pt and metal M's standard curve. Spectral analysis of the test sample using ICP, plotting the Pt and metal M curves, analyzing the concentration of Pt or Pt in the sample to be tested Alloy metal M concentration. 4.2.8 Data Processing Calculate Pt content in electrocatalyst according to formula (2). In the formula. ηPt---The content of Pt in the electrocatalyst, the unit is %; Shape --- the test sample is prepared as the dilution of the ICP analysis solution; Pt concentration in CPt-ICP test solution in milligrams per liter (mg/L); 犞Pt---The initial volume of the prepared test sample, in litres (L); Calculate the content of alloy metal M in the electrocatalyst according to formula (3). In the formula. ηM --- the content of alloy metal M in the electrocatalyst, the unit is %; Shape --- the test sample is prepared as the dilution of the ICP analysis solution; The concentration of alloy metal M in the CM-ICP test solution in milligrams per liter (mg/L); 犞Pt---The initial volume of the prepared test sample in liters (L); 5 Electrochemically active area (ECA) test 5.1 Test Instruments Electrochemical constant potential tester. 5.2 Sample preparation The test sample should be placed in a vacuum oven at 80°C for 12 hours. The sample quality should meet the requirements of 3 effective tests. 5.3 Test Methods 5.3.1 Accurately weigh 5mg ± 0.05mg of catalyst. 5.3.2 Into the weighed catalyst, 50 μL of a 5% Nafion (DE521) solution, 2 mL of deionized water, and 2 mL of isopropanol were sequentially added. 5.3.3 Ultrasonic with ultrasonic power of not less than.200W for 30 min, so that the slurry is mixed evenly, and the temperature of the bath must be maintained during the ultrasonic process. Over 20°C. 5.3.4 According to the electrode surface catalyst loading 50μg/cm 2～200μg/cm 2, take the appropriate amount of dispersed slurry is divided into two drops It is applied to the surface of a smooth and clean disk electrode and allowed to dry naturally and completely as a working electrode. 5.3.5 The electrode is placed in an electrolytic cell to form a three-electrode system. Among them, the reference electrode is saturated calomel electrode (Hg/Hg2Cl2/saturation KCl solution) or silver chloride electrode (Ag/AgCl/saturated KCl solution) with a large area Pt plate or Pt wire for the counter electrode and N2 saturation of the electrolyte 0.5mol/L H2SO4 solution; 5.3.6 Test the cyclic voltammogram. The catalyst was first activated at a scan rate of 20mV/s until the hydrogen desorption peak area (Figures When no longer increasing, 5 cycles are scanned at a rate of 20 mV/s, and the potential scan range is -0.25 V to 1.0 V (vs. saturated calomel pole). 5.4 Data Processing Voltage/VvsSCE For the Pt/C catalyst, a typical cyclic voltammogram obtained by electrochemically testing ECA is shown in FIG. Select the stabilized cyclic voltammogram and integrate its hydrogen desorption peak to obtain the area S(A·V). Calculate the electrochemistry according to equation (4). Active area ECA. ECA=100×S/(C×ν×M) (4) In the formula. ECA - electrochemically active area in square meters per gram (m2/g); S --- integrated area of hydrogen desorption peaks, in volts (A · V); C---adsorption constant of absorbed hydrogen peroxide on surface of smooth Pt, 0.21 millicoulombs per square centimeter (0.21mC/cm2); ν --- scanning speed in millivolts per second (mV/s); M---The mass of Pt on the electrode in grams (g). Take 3 samples as a group and calculate the average as the test result. 6 Specific surface area, pore volume, pore size distribution test Refer to GB/T 5816-1995 for testing. 6.1 Instruments and Gases 6.1.1 Fully automatic physical adsorption instrument. 6.1.2 Analytical balance. The precision is 0.01mg. 6.1.3 Test gas. The oil-free high-purity nitrogen gas and helium gas after drying have a purity of not less than 99.999%. 6.2 Test Methods The static nitrogen adsorption capacity method is used to measure the volume of nitrogen adsorbed on the catalyst at different low pressures. It must be measured at least according to the BET linearity. At the four test points of the system, surface area calculations were performed using the BET two-parameter equation. 6.2.1 Sample Pretreatment and Degassing b) Take the appropriate amount of sample into the sample tube. Set the heating temperature (generally less than.200°C) and heat the sample. When heating temperature When the temperature reaches the set temperature and the system vacuum reaches 1.3 Pa, degassing is continued for at least 4 hours. Allow the sample to degas overnight; The difference is given the sample net weight. 6.2.2 Determination of Dead Space a) Fill the analysis system manifold to 79.9kPa to 119.9kPa according to the analysis requirements, and record the pressure and manifold temperature. With After opening the sample valve to be tested, the helium gas is filled into the sample tube; b) After about 5 minutes of equilibrium, record the equilibrium pressure and manifold temperature. Based on the recorded pressure and manifold temperature and the known manifold volume, Accurately calculate dead space. 6.2.3 Determination of Adsorption a) Fill the system with nitrogen as required by the analysis, and measure more than four adsorption tests with a relative pressure P/P0 of 0.06 to 0.2 or 0.25. Checkpoint. Record the corresponding equilibrium pressure P, and calculate the adsorption amount 犞a; b) When the adsorption is measured, the pressure change does not exceed 13 Pa within 5 min, which can be considered as reaching the adsorption equilibrium; c) Measure and record the saturated vapor pressure of liquid nitrogen, P0. 6.3 Result Calculation a) According to the formula (5) BET two-parameter equation. P/P0 犞a(1-P/P0)= 犞m×C+ C-1 犞m×C× P/P0 (5) In the formula. P/P0---relative pressure; P---balanced pressure in kPa (kPa); P0 --- saturated vapor pressure in kPa (kPa); 犞a---nitrogen adsorption capacity in cm3STP/g; 犞m---adsorption amount in single layer, unit is cm3STP/g; C--- constants related to the net molar adsorption heat of nitrogen. With P/P0 pair P/P0 犞a(1-P/P0) To make a BET line graph, determine the cut of the BET line graph directly from the graphical method or least squares method The distance I is 1 犞 m × () C and the slope S is C-1 犞 m × () C. Within the selected BET line range, each test point deviates from the straight line by no more than 0.6% of the ordinate value. b) The monolayer adsorption amount 犞m (cm3STP/g) is calculated according to formula (6). 犞m = 1S+I (6) In the formula. 犞m---adsorption amount in single layer, unit is cm3STP/g; S--- slope of BET line graph; Intercept of I---- BET line diagram. c) The surface area of the sample, SBET (m2/g), is calculated according to Equation (7) (The molecular nitrogen cross-sectional area is taken as 0.162 nm2). SBET =4.353×犞m (7) In the formula. SBET --- surface area of the sample, in m2/g; 犞m---The adsorption amount of single layer, the unit is cm3STP/g. d) The pore size distribution is obtained from the BJH model and processed by software.

7 Morphology and particle size distribution test

7.1 Test Instruments A transmission electron microscope that meets the requirements for different catalyst particle size tests. 7.2 Sample preparation The single sample powder size should be less than 1 μm. Prior to testing, the samples were dried in a vacuum oven at 80°C for 12 h. 7.3 Test Methods 7.3.1 The copper net is degreasing and decontaminated, and cleaned and dried. 7.3.2 Take an appropriate amount of sample and ethanol into a small beaker, sonicated and evenly mixed. Drop a suitable amount of the mixture onto a copper mesh, dry it, and place it in the transmission. Electron microscope instruments are tested. 7.3.3 In accordance with the operating requirements of the electron microscope instrument, take a photo of the electron microscope at a certain magnification. 7.4 Data Processing The particle size of more than.200 sample particles was counted and the particle size distribution chart was given. Calculate the average particle size of the sample according to equation (8). Dm = ∑ In the formula. Dm --- the average particle size of the catalyst particles, in nanometers (nm);

8 Crystal structure test

8.1 Test Instruments X-ray diffractometer (XRD). 8.2 Sample preparation The amount of catalyst sample is not less than the amount needed to fill the sample cell. After the sample was dried in a vacuum oven at 80[deg.] C. for 12 h to complete drying, it was ground to a fine powder with a particle size of less than 100 nm. 8.3 Test Methods 8.3.1 Place the sample in the sample cell and press it with a piece of glass. The surface of the sample should be flush with the surface of the sample well to prevent XRD pattern shift. 8.3.2 Place the sample cell in the sample holder of the XRD tester. 8.3.3 Scan the sample at a sweep rate and angle to obtain a catalyst XRD pattern. 8.4 Data Processing and Reporting In contrast to the standard spectrum library, the crystal structure of the catalyst was determined. Estimate the average particle size of the sample according to equation (9). D=0.9λ/(β×cosθ) (9) In the formula. D --- grain size, in nanometers (nm); λ --- X-ray wavelength in nanometers (nm); β - half width, unit is radian (rad); θ--- diffraction angle in degrees (°).

9 Bulk density test

9.1 Sample Preparation Take 1.0 g of the catalyst and place it in a vacuum oven at 80° C. for 12 h as a sample to be tested. 9.2 Test Instruments 9.2.1 Analytical balance. The accuracy is 0.1mg. 9.2.2 Measuring cylinder. The accuracy is 0.1mL. 9.3 Test Methods Refer to the method in GB/T 13566-1992. 9.3.1 Weigh the measuring cylinder and record it as M1 with an accuracy of 0.1 mg. 9.3.2 Use a test funnel to pour a certain amount of sample into the measurement cylinder within 20s to 25s. The sample volume must be more than full. Measure the required amount of cartridge. During the pour-in process, tap the measuring cylinder wall twice with the frequency of 2 to 3 times per second to make the sample compact. If the sample flow is not smooth, use a glass rod with a diameter of about 4mm to clean the funnel outlet to make it clear. 9.3.3 Close the funnel, then raise the measuring cylinder by 2mm~3mm to make it fall down to further compress the sample, repeat the operation 20 times, read The volume of the sample, 犞 (mL). 9.3.4 Weigh the measuring cylinder and the total mass of the sample, denoted as M2, to the nearest 0.1 mg. 9.4 Data Processing Calculate the bulk density of the sample according to equation (10). ρ= (M2-M1)/犞 (10) In the formula. ρ---The bulk density of the sample in grams per milliliter or grams per cubic centimeter (g/mL or g/cm 3); M2 --- the total mass of the measuring cylinder and the sample, in grams (g); M1 - the mass of the measuring cylinder in grams (g); 犞--- The volume of the sample in milliliters or cubic centimeters (mL or cm3). Take 3 samples as a group and calculate the average as the test result. 10 Cell Polarization Curve Test 10.1 Sample Preparation A certain amount of catalyst was taken and dried in a vacuum oven at 80°C for 12 hours as a sample to be tested. The sample quality should meet the requirements of 3 effective tests. 10.2 Test Equipment and Materials 10.2.1 End plates. The compressive strength shall meet the requirements for the assembly pressure of the proton exchange membrane fuel cell. 10.2.2 Flow field plate and current collector plate. The flow field plate is a pure graphite plate with a computer-engraved serpentine flow field. Current collector plate is gold plated or silver plated Rust steel plate. 10.2.3 Fuel Cell Test Platform. The schematic diagram of the proton exchange membrane fuel cell test platform is shown in Figure 2. 1---Battery; 2 --- humidifying tank; 3--- gas-water separation tank; 4 --- flowmeter; 5--- external circuit; 6 --- pressure gauge; 7 --- tail valve; 8 --- water valve; 9---H2 mass flow controller (MFC); 10---Air/O2 Mass Flow Controller (MFC). Note. After decompression of the reaction gas, the inlet flow rate is controlled by the mass flow contro......
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