A small-scale and portable 50Â W PEMFC system that automatically generates hydrogen from a mixture of Al, CaO, NaOH and sodium CMC in water without external power supply

The production of hydrogen from water under kinetic control is studied using a hydrophobic pouch filled with a mixture of aluminum, calcium oxide, water-soluble alkaline sodium CMC (Carboxymethylcellulose), and sodium hydroxide particles. NaOH particles easily absorb moisture from the air. Thus, CaO is added to protect NaOH from melting. To control the hydrogen generation rate, the aluminum powder is shaped into the spherical solids (M1) and irregular pellets (M2) using the alkaline sodium CMC. The hydrogen-generating pouch is prepared before hydrogen generation rate test. Results show that the best recipe for the range test is 40 wt% M1, 48 wt% M2, and 12 wt% mixed powder including NaOH, CaO and NaHCO3, because of its greater stability and high hydrogen concentration. The best ratio of the aluminum powder and alkaline sodium CMC in three tests is 95 wt% to 5 wt%. The reaction of the pouch and water produces an on-board hydrogen supply for a polymer electrolyte membrane fuel cell (PEMFC) that can remain stable for 5 h or more, without requiring the addition of energy. This pouch has been applied in small-scale to large-capacity hydrogen generators for the PEMFC. Furthermore, this pouch has been used successfully to develop a 50 W portable hydrogen PEMFC generator.