GB/T 20042.4-2009 PDF English
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Proton exchange membrane fuel cell -- Part 4: Test method for electrocatalysts
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GB/T 20042.4-2009: PDF in English (GBT 20042.4-2009) GB/T 20042.4-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.070
K 82
Proton exchange membrane fuel cell –
Part 4. Test method for electrocatalysts
ISSUED ON. APRIL 21, 2009
IMPLEMENTED ON. NOVEMBER 01, 2009
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword . 3
1 Scope .. 4
2 Normative references . 4
3 Terms and definitions . 4
4 Platinum content test .. 5
5 Electrochemical active area (ECA) test .. 8
6 Specific surface area, pore volume, pore size distribution test .. 10
7 Morphology and particle size distribution test . 12
8 Crystal structure test . 13
9 Stack density test .. 14
10 Single cell polarization curve test . 15
Appendix A (Informative) Test preparation . 24
Proton exchange membrane fuel cell –
Part 4. Test method for electrocatalysts
1 Scope
This part of GB/T 20042 specifies the terminology and definition, 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 bulk density test, and single cell polarization curve
test of the electrocatalyst test method for proton exchange membrane fuel cells.
This part applies to various types of platinum-based (Pt-based) electrocatalyst
for proton exchange membrane fuel cell.
2 Normative references
The provisions in following documents become the provisions of this part
through reference in GB/T 20042. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this Standard;
however, parties who reach an agreement based on this Standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 5816-1995 Catalyst and adsorbents - Determination of surface area
GB/T 13566-1992 Determination of bulk density for fertilizers (ISO
3944.1980, EQV)
GB/T 15072.7-2008 Test methods of precious metal alloys - Determination
of chromium and iron contents for gold alloys - Inductively coupled plasma
atomic emission spectrometry
GB/T 20042.1 Proton exchange membrane fuel cell - Terminology
3 Terms and definitions
The terms and definitions defined in GB/T 20042.1 and the following terms and
definitions apply to this part.
Electrochemical active area
L - Pt loading capacity, in unit of %;
W1 - The mass of the sample at endpoint temperature, in milligrams (mg);
W0 - The original mass of the sample, in milligrams (mg).
TAKE 3 samples as a group, CALCULKATE the average value as the test result.
4.2 Pt content test by ICP (inductively coupled plasma spectroscopy)
method
The test is performed in accordance with the method as specified in GB/T
15072.7-2008.
4.2.1 Scope of application
This method is suitable for testing Pt content in Pt/C catalysts and Pt alloy
catalysts.
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 precision is 0.1 mg.
4.2.2.3 Caliper. The measurement precision is 0.01 mm.
4.2.3 Sample preparation
The sample mass is not less than 2 g.
The sample is placed in a vacuum oven and dried at 80 °C for 12 h.
4.2.4 Reagents and materials
4.2.4.1 Concentrated sulfuric acid (98%), guaranteed reagent.
4.2.4.2 Concentrated hydrochloric acid (37%), guaranteed reagent.
4.2.4.3 Concentrated nitric acid (68%), guaranteed reagent.
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 Corundum crucible with cover.
4.2.5 Test method
C - Smooth Pt surface adsorption hydrogen peroxide adsorption constant, in
0.21 millicoulombs per square centimeter (0.21 mC/cm2);
v - 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, CALCULATE the average value as the test result.
6 Specific surface area, pore volume, pore size
distribution test
The test is performed in accordance with the method as specified in GB/T 5816-
1995.
6.1 Instruments and gases
6.1.1 Fully automatic physical adsorption instrument.
6.1.2 Analytical balance. the precision is 0.01 mg.
6.1.3 Test gas. The oil-free high-purity nitrogen gas and helium gas after drying,
the purity is not less than 99.999%.
6.2 Test methods
The static nitrogen adsorption capacity method is used to measure the volume
of nitrogen adsorbed by the catalyst at different low pressures. At least four test
points satisfying the BET linear relationship are measured, and the surface area
is calculated using the BET two-parameter equation.
6.2.1 Sample pretreatment and degassing
a) In accordance with the degassing requirements, PLUG the empty sample
tube after degassing treatment to weigh it, accurate to 0.01 mg. At this
point the mass is recorded as m1;
b) TAKE the appropriate amount of sample and ADD it into the sample tube.
SET the heating temperature (generally less than 200 °C) to heat the
sample and EMPTY it. When the heating temperature reaches the set
temperature and the system vacuum reaches 1.3 Pa, CONTINUE
degassing for at least 4 hours. It is allowed for the sample to be degassed
overnight;
c) COOL the degassed sample tube to room temperature, ADD plug to weigh
it, accurate to 0.01 mg. This mass is recorded as m2, and the difference
to 0.1 mg.
9.3.2 USE a test funnel, POUR a certain amount of sample into the measuring
cylinder within 20 s ~ 25 s. The sample volume must exceed the amount
required to fill the measurement cylinder full. During the pour-in process, USE
a rod to gently knock the measuring cylinder wall at the frequency of 2 ~ 3 times
per second, to make the sample compact. If the sample flow is not smooth, it
may use a glass rod with a diameter of about 4 mm to clean the funnel discharge
port to make it unblocked.
9.3.3 CLOSE the funnel, then RAISE the measuring cylinder by 2 mm ~ 3 mm,
LET it fall down to further compress the sample, REPEAT this operation for 20
times, READ out the sample volume (mL).
9.3.4 WEIGH the total mass of the measuring cylinder and the sample,
RECORD it as M2, accurate to 0.1 mg.
9.4 Data processing
CALCULATE the stack density of the sample in accordance with the formula
(10).
Where.
ρ - The stack density of the sample, in grams per milliliter or grams per cubic
centimeter (g/mL or g/cm3);
M2 - The total mass of the measuring cylinder and the sample, in grams (g);
M1 - The mass of the measuring cylinder, in grams (g);
V - The volume of the sample, in milliliters or cubic centimeters (mL or cm3).
TAKE 3 samples as a group, CALCULATE the average value as the test result.
10 Single cell polarization curve test
10.1 Sample preparation
TAKE a certain amount of the catalyst, PLACE it in a vacuum oven at 80 °C to
dry it for 12 hours, which is used as a sample to be tested.
The sample mass shall meet the requirements of 3 valid tests.
10.2 Test instrument equipment and materials
connecting the electronic load. Among them, the current meter adjustment
precision is not less than 0.01 A; voltmeter range. ≥ 2V, adjustment time ≤ 100
ms. H2 mass flow controller (MFC). precision ≥ ± 1% FS; Air/O2 mass flow
controller. precision ≥ ± 1% FS. Temperature control meter range. room
temperature -200 °C, precision ≥ ± 1 °C. Pressure gauge. precision ≥ ± 1% FS.
Figure 2 -- Schematic diagram of proton exchange membrane fuel cell
test platform
10.2.4 Test gas and water
10.2.4.1 H2. Compressed H2 with a purity≥ 99.999%, after bubbling
humidification, it is subject to pipeline thermal insulation and enter the test cell,
the pipeline temperature is not lower than the humidification temperature.
10.2.4.2 O2. Compressed O2 with a purity ≥ 99.999%, after bubbling
humidification, it is subject to pipeline thermal insulation and enter the test cell,
the pipeline temperature is not lower than the humidification temperature.
10.2.4.3 Deionized water for humidification. Conductivity < 0.25 μS/cm.
10.2.5 Gas diffusion layer
The diffusion layer adopts the Sigracet GDL 30BC commercialized by SGL.
10.2.6 Proton conductor
The proton conductors uniformly use the Nafion solution of DE512 model, which
is commercially available from DuPont.
10.3 Test procedure
10.3.1 Catalytic layer preparation by screen-printing
10.3.1.1 Based on the anode Pt loading 0.3 mg/cm2, the cathode Pt loading 0.5
mg/cm2, the Pt content in the catalyst, and screen-printing electrode area 50
cm2, CALCULATE the amount of catalyst which is used to prepare the catalyst
layer, WEIGH it, accurate to 0.1 mg.
10.3.1.2 After sufficiently wetting the catalyst with a small amount of deionized
water, ADD the lower alcohol (ethanol, isopropanol, ethylene glycol, etc.) as a
dispersant in accordance with the ratio of W catalyst . W dispersant = 1.15.
DISPERSE the above mixture ultrasonically in an ultrasonic wave, while stirring
it clockwise, to ensure that the liquid material is homogeneous along each
direction, and free from lump, blocking, or particle.
10.3.1.3 Based on the ratio of the amount of carbon powder in the catalyst to
the amount of Nafion at L carbon . L NetNafion = 1.0.8, ADD the 5% Nafion solution
two requirements shall be met.
(1) CONTROL and RECORD the pressure at the cathode inlet, to ensure
that water in the U-tube does not enter the cell.
(2) The detection gas pressure must be stable. Otherwise, the stable
pressure difference cannot be read. It cannot be judged whether the
pressure difference i...
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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