GB/T 20042.4-2025Proton exchange membrane fuel cell — Part 4: Test method for electrocatalysts (English PDF)

3 Terms and definitions

4 General safety requirements

5 Moisture content test

6 Testing of the content of metallic elements

7 Determination of specific surface area and pore size distribution

8 Test for morphology and particle size distribution

9 Test for crystal structure and average particle size

10 Bulk density test

11 Half-cell electrochemical active surface area (ECSA) test

12 Half-cell oxygen reduction (ORR) polarization curve test

13 Durability test of half-cell ORR catalysts

14 High-potential durability test of half-cell ORR catalysts

15 Testing of the dissolution rate of metallic elements

16 High-potential durability test of half-cell HOR catalysts

17 CO tolerance test of half-cell HOR catalysts

Foreword

This document was issued on 29 August 2025 by the State Administration for Market Regulation and the Standardization Administration of the People's Republic of China, and has been in force since 1 March 2026.

It replaces GB/T 20042.4-2009.

The document is under the responsibility of the China Electrical Equipment Industry Association.

Classification: ICS 27.070, CCS K 82.

About this edition

GB/T 20042.4-2025 is the current edition. It was issued on 29 August 2025 and has been in force since 1 March 2026, replacing GB/T 20042.4-2009.

GB/T 20042.4-2009 has been superseded: a specification that still cites it is citing a withdrawn edition.

The interval between issue and effect is the transition period. It exists so that producers, laboratories and buyers can requalify products, revise procedures and use up documentation before the new text becomes the one that applies. The date on this page is the official one from the record of the Standardization Administration.

Classification and status

GB/T 20042.4-2025 is classified under ICS 27.070, in the field of energy and heat transfer engineering. ICS is the International Classification for Standards, the same scheme used by ISO and by the national bodies of most countries, which is what allows a Chinese standard to be placed beside its foreign counterparts on subject rather than on number.

Its Chinese Standard Classification code is CCS K 82. CCS is the domestic scheme, a letter for the sector and two digits for the subject within it, and it is the code by which the standard is filed and searched in China.

The GB/T prefix marks a recommended national standard. It is not, in itself, law: it becomes binding when a contract names it, when a regulation or a mandatory standard refers to it, or when a producer declares conformity with it. In practice that covers most of the cases in which it will be read — a purchase specification, an inspection agreement or a certification scheme.

The document is under the responsibility of the China Electrical Equipment Industry Association, which is the body that maintains it and that will answer a formal question about its interpretation.