Regenerating Hydrogen-Fuel Storage Material

Taking a step toward a world powered by hydrogen, rather than predominantly by fossil fuels, researchers from Los Alamos National Laboratory and the University of Alabama have developed a simple method for recycling ammonia borane (NH₃BH₃), a potential hydrogen-rich fuel (Science, DOI: 10.1126/science.1199003). Although scientists have made recent progress in catalyzing the release of H₂ from the storage compound NH₃BH₃, “a big piece of the puzzle still missing is how to recharge the spent fuel,” says Karen I. Goldberg, a catalysis researcher at the University of Washington. Release of more than two equivalents of H₂ from NH₃BH₃ results in the formation of the spent-fuel compound polyborazylene. By mixing this spent-fuel compound with hydrazine (N₂H₄) in liquid ammonia at 40 °C for 24 hours, the research team was able to regenerate the NH₃BH₃ at 92% yield. For the process to become industrially useful, manufacturers would need to address the production, cost, and safety of hydrazine, but this regeneration scheme is an “exciting” development in the field of chemical hydrogen storage, Goldberg says.