Trace level analysis of reactive ISO 14687 impurities in hydrogen fuel using laser-based spectroscopic detection methods

Hydrogen fuelled vehicles can play a key role in the decarbonisation of transport and reducing emissions. To ensure the durability of fuel cells, a specification has been developed (ISO 14687), setting upper limits to the amount fraction of a series of impurities. Demonstrating conformity with this standard requires demonstrating by measurement that the actual levels of the impurities are below the thresholds. Currently the industry is unable to do so, for measurement standards and sensitive dedicated analytical methods are lacking. In this work, we report on the development of such measurement standards and methods for four reactive components: formaldehyde, formic acid, hydrogen chloride and hydrogen fluoride. The primary measurement standard is based on permeation, and the analytical methods on highly sensitive and selective laser-based spectroscopic techniques. Relative expanded uncertainties at the ISO 14687 threshold level in hydrogen of 4% (formaldehyde), 8% (formic acid), 5% (hydrogen chloride), and 8% (hydrogen fluoride) have been achieved.