Microreactors for Syngas Conversion to Higher Alkanes: Characterization of Sol-Gel-Encapsulated Nanoscale Fe-Co Catalysts in the Microchannels

Silicon microreactors have been coated with mixed-metal Fe-Co Fischer-Tropsch catalysts in alumina sol-gel for conversion of syngas (CO + H2) to higher alkanes. Characterization of the nanocatalysts using scanning electron microscopy, energy-dispersive X-ray, atomic force microscopy, and Brunauer-EmmettTeller surface area measurements, packaging, and the reaction results from a mass spectrometer at controlled temperatures (200-260 (degree)C) and pressure (1 atm) with varying H2:CO ratios from 1:1 to 10:1 are described. The catalyst does not adequately infiltrate the 5-(mu)m channels; it coats nicely the 25-(mu)m channels. The initial results are consistent with a lower conversion of CO (~32%) in a 5-(mu)m-channel reactor and a higher conversion (~52%) in a 25-(mu)mchannel reactor. The selectivity to propane (~80%) is not affected by the width of the microchannels. The activity of the sol-gel-encapsulated catalyst before and after the reactions is estimated from its magnetic properties using a vibrating sample magnetometer.