Silicon-based micro-reactor for preferential CO oxidation

A silicon-based micro-reactor was fabricated using a micro-electromechanical system (MEMS) process and silicon micromachining technology (SMT) to allow preferential CO oxidation (PrOx) to be applied to compact portable devices. To design the micro-PrOx reactor, the effects of channel length, channel width, channel array, and O2 content in the reactant gas on the CO conversion and selectivity for CO were investigated. The single micro-PrOx reactor required an O2 concentration four times higher than the theoretical quantity for a complete conversion of 1% CO into CO2. The optimum operating temperature to obtain high CO conversion, by suppressing the reverse water–gas shift (r-WGS) reaction, depended considerably on the channel lengths of the micro-reactor rather than on the channel widths or the channel arrays. The micro-PrOx reactor showed 99.4% conversion of CO and 44.14% selectivity for CO at 260 °C when operating with 1% CO, 50% H2, 35% CO2, N2 (balance), and 2% O2.