Porous anodic alumina microreactors for production of hydrogen from ammonia

The synthesis and properties are described of a ruthenium-impregnated anodic aluminum catalyst for use in microreactors for the production of hydrogen from all ammonia feed. The catalyst structure was synthesized using microelectric discharge machining to create a series of 300 x 300-mum posts on all aluminum substrate. The posts were anodized to yield a 60-mum covering of anodic alumina, with an average surface area of 16 m(2)/gm and all average pore size of 50 nm. Ruthenium metal was dispersed oil the alumina using conventional wet impregnation. A 0.9 x 0.9-cm reactor containing 250 posts decomposed 95% of anhydrous ammonia at 650degreesC to yield 15 sccm of hydrogen. A possible application of these microreactor fabrication methods is hydrogen generation for fuel cells in mobile power production. (C) 2004 American Institute of Chemical Engineers.