Evaluation of Low Temperature CO Removal Catalysts

Carbon monoxide removal from spacecraft gas streams was evaluated for three low temperature oxidation catalysts: Carulite 300, Sofnocat 423, and Hamilton Sundstrand Pt1. The catalysts were challenged with CO concentrations (1-100 ppm) under dry and wet (40- 50% relative humidity) conditions using 2-3% O2. Carbon monoxide removal and CO2 concentration were measured at constant feed composition using an FTIR. Water vapor affected the CO conversion of each catalyst differently. An initial screening found that Carulite 300 could not operate in humid conditions. The presence of water vapor affected CO conversion of Sofnocat 423 for challenge concentrations below 40 ppm. The conversion of CO by Sofnocat 423 was 80% at CO concentrations greater than 40 ppm under both dry and moist conditions. The HS Pt1 catalyst exhibited CO conversion levels of 100% under both dry and moist conditions and low CO concentrations.