Nanoscale Platinum Catalyst in Microreactors for Preferential Oxidation of CO for Hydrogen Fuel Cell Feeds

摘要

Oxidative removal of a small quantity of CO from a hydrogen atmosphere has been attempted by using nano-scale impregnated platinum coated silicon based sol-gel in a microreactor. The microreactor with 25 μm wide channels was fabricated by general photolithography and Inductively Coupled Plama (ICP) dry etching. The catalytic preferential oxidation of CO was observed over a temperature range from 393 to 493 K. Air or pure O_2 was the oxidizer. The effects of temperature, total flow rate and ratio of O_2/CO on the conversion and selectivity are presented. A statistical design of experiment approach was implemented to minimize the experiments necessary for the study. The conversion of CO reaches 91% at 160 ℃, O_2/CO ratio of 0.5 and a WHSV of 13 h~(-1), while the highest selectivity to CO_2 is 90%. At higher temperatures, the oxidation of H_2 increases and the selectivity to CO oxidation decreases. Deactivation of the platinum catalyst was observed over a period of 50 hours of reaction time.