An ammonia-borane based hydrogen storage system for portable applications

FUEL 103

Nahid Mohajeri, nmohajeri@fsec.ucf.edu1, Olawale Adebiyi1, Jong Baik2, Gary Bokerman1, and Ali T-Raissi1. (1) Hydrogen R&D, University of Central Florida-Florida Solar Energy Center, 1679 CLearlake Rd., Cocoa, FL 32922-5703, (2) Florida Solar Energy Center, University of Central Florida, 1679 CLearlake Rd., Cocoa, FL 32922-5703
Ammonia-borane (AB) complex is a chemical hydride with very high hydrogen content (19.6 wt%). In this paper, we present a new process for generating hydrogen via hydrolysis of AB, which yields 3 moles of H2 and one mole of NH3. Phosphoric acid was used as a sequestering agent due to its superior performance in removing NH3 and minimum pull down on the system-level gravimetric hydrogen storage density.

Hydrogen was generated by reacting an aqueous solution, containing Na3Cl6Rh catalyst and phosphoric acid, at a rate of 0.025 mL/min isothermally at 70 C with AB. Rate of hydrogen evolution tripled when the injection rate was increased to 0.050 mL/min. Hydrogen production rates were essentially unchanged when the hydrogen generator operated adiabatically. When AB complex, in the form of pellets or tablets, were added periodically, one tablet at a time, to the catalytic solution at 80 C, much higher rate of H2 production was observed.