Clean Catalysts for Water Recovery Systems in Long-Duration Missions

A catalytic post-processor is the last unit operation that reclaimed water typically sees before being consumed by the crew, therefore the entire sub-system must be safe, reliable and well-understood. The key innovation required to provide a sub-system for longer-term missions is to develop catalyst technologies that maintain a high degree of activity and physical stability over multi-year operational lives. The high catalytic activity of noble metals combined with the surface area and adsorptivity of activated carbon are the ideal combination of parameters for achieving the highest level of performance at the lowest penalty for a post-processing sub-system. The problem has been the physical breakdown of traditional activated carbon catalyst supports. To address this problem, the Phase I and previous intermittent research efforts have shown that noble metal catalysts supported on Porous Solid Carbon, exhibit superior physical properties to alumina, ceramic and granular activated carbon-supported catalysts currently used by NASA and throughout the chemical process industries. The Porous Solid Carbon-based catalysts are proposed due to their remarkable hardness and physical stability combined with their high surface area and surface activity. Phase I continued the successful demonstration and scale-up of the technology, demonstrating that the reactors can be manufactured with high surface area and porosity and good internal consistency, as well as demonstrating that the catalytic activity is extremely high under very mild conditions. The Porous Solid carbon reactor scale-up will be completed in Phase II to International Space Station-sized reactors that will be fabricated, tested and characterized using advanced analytical methods that will yield a fully quailifiable protocol for manufacturing the reactors for Phase III flight implementation.