(520b) Silicon Micro-Reactors to Power Portable Electronics

An innovative silicon based micro-machined platform is designed to deliver clean energy for portable electronic applications. The work involves the incorporation of nickel microfibers to entrap supported catalysts for ammonia decomposition in a silicon microreactor that exhibits high per pass conversions. The micro-reactor is fabricated using standard bulk micromachining technique within a single crystal silicon wafer and sealed by a pyrex plate using anodic bonding. A novel nickel microfibrous media with close to 50 % voidage made using the wet lay process is very effectively used to entrap ruthenium and platinum catalysts on silica supports. The micro-reactors have an overall reactor volume of 150 μl and can produce hydrogen at a rate of 300-cc/min/cc reactor volumes, which is equivalent to 30 W for fuel cell operations. These hydrogen production rates satisfy the requirements for practical operation of reactors for portable electronic applications and have surpassed the results that have been previously reported in literature. The nickel mesh enhances volume productivity and the micro reactors by itself significantly improve the heat and mass transfer attributed to high surface to volume ratio, thus leading to higher turnover frequencies resulting in higher conversions.