Analytical Metrology in Support of the U.S. Hydrogen Infrastructure

Under the initiative "Enabling the Hydrogen Economy," NIST will apply its unique facilities and expertise in the multi-agency effort to make hydrogen fuel an effective economical and safe alternative to carbon-based fuels. Enabling the Hydrogen Economy consists of four challenges; 1) Making better fuel cells; 2) Storing more hydrogen; 3) Creating consensus standards; and 4) Ensuring fair trade. The Analytical Chemistry Division is involved in projects to support challenges 2 and 4.

Storing more hydrogen

No existing hydrogen storage materials satisfy the Department of Energy's goal for achieving a commercial hydrogen storage system for competitive hydrogen-powered transportation. A key to accelerating the development of such innovative materials is a detailed understanding of elemental stoichiometry and the embedded impurities that may enhance or detract from hydrogen storage capacities. Today’s methods of material synthesis generate only test quantities that require rapid chemical and impurity analysis, preferably by nondestructive techniques. Prompt gamma activation analysis (PGAA) and instrumental neutron activation analysis (INAA) are uniquely suitable for the task. PGAA can determine low-Z elements such as H, B, Mg, etc. Determining these elements by any other nondestructive techniques is neither trivial nor reliable. We are developing both PGAA and INAA procedures for accurate characterization of hydrogen storage materials.

Ensuring fair trade

SAE has proposed a Hydrogen Fuel Quality Specification Guideline. Several contaminants, in particular sulfur containing compounds, have been identified that will be detrimental to the performance of the hydrogen cell. NIST has begun the development of standard preparation and analytical methodology for: hydrogen sulfide (H₂S); carbonyl sulfide (COS); methyl mercaptan (CH₃SH) and ammonia (NH₃).

• Constructed major components for the new PGAA instrument at NCNR with environmental chamber.
• Decreased detection limits for sulfur containing compounds, ammonia, formaldehyde and VOCs which are critical impurities that negatively affect hydrogen fuel cell efficiency.