The NASA JSC Engineering Technology and Science contract focuses on developing life support and emergency response equipment for space missions. This includes the Contingency Breathing Apparatus (CBA) and Orion Smoke Eater Filter (OSEF), designed to address fire-related particulates and noxious gases aboard the Orion Multi-Purpose Crew Vehicle. However, the existing TDA catalyst (from TDA Research Inc.) in NASA's CBA and OSEF systems is costly and susceptible to damage. Recent advancements have introduced more cost-effective and durable catalysts by various manufacturers. This study extends our previous work by comparing the TDA catalyst with a commercially available CO oxidation catalyst developed by Astrea Materials. The catalyst performance was assessed for CO oxidation across varying temperatures, flowrates, and relative humidity levels. Furthermore, the mechanical strength of both catalysts during handling and mechanistic factors contributing to performance degradation were evaluated. Attrition tests revealed that the TDA catalyst was more prone to dust generation than the Astrea catalyst, which exhibited better resilience in attrition and compression tests. The BET surface area of the Astrea catalyst was ~1.5 times that of the TDA counterpart. The performance of the TDA catalyst, in terms of CO oxidation per unit volume of the bed, was superior to that of the Astrea catalyst at different temperatures and humidity levels. ICP and XPS techniques were employed to determine the bulk and surface composition, respectively, of the catalysts. The XPS analysis revealed changes in the catalytic (Au) and support materials when exposed to CO. SEM analysis showed a more agglomerated surface morphology in the Astrea catalyst compared to its TDA counterpart. This study established the significance of systematic XPS, in situ FTIR, and TEM analyses in revealing chemical and morphological changes on the surface and bulk of the catalysts, thereby enabling the identification of the mechanistic causes of their deactivation.
Yaparatne et al. (Sun,) studied this question.