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 an ammonia feed. The catalyst structure was synthesized using microelectric discharge machining to create a series of 300 X 300-μm posts on an aluminum substrate. The posts were anodized to yield a 60-μm covering of anodic alumina, with an average surface area of 16 m²/gm and an average pore size of 50 nm. Ruthenium metal was dispersed on the alumina using conventional wet impregnation. A 0.9 X 0.9-cm reactor containing 250 posts decomposed 95% of anhydrous ammonia at 650°C to yield 15 sccm of hydrogen. A possible application of these microreactor fabrication methods is hydrogen generation for fuel cells in mobile power production.