Photocatalytic Oxidation of Gas-Phase Compounds in Confined Areas: Investigation of Multiple Component Systems

Photocatalytic oxidation (or photocatalysis) can be used to convert undesirable compounds present in gas or liquid samples into carbon dioxide and water. Photocatalyst materials are “self-generating”, making the process especially attractive in moderate and long-term applications where consumable materials are to be avoided (e.g., Space Shuttle cabins and in the International Space Station). Photocatalytic studies have traditionally been performed in the presence of a single test compound—a single component system. However, real world application of the technology will most certainly occur in the presence of multiple reactive compounds. In this study, single component photocatalysis experiments were performed on a set of three-carbon compounds that contain different functionality (propane, propene, acetone and propanal). The relative time required for degradation of the compounds was directly dependent upon the predicted affinity for the catalyst surface. In multi-component experiments, compounds with lower affinity for the catalyst surface did not degrade until the higher affinity compounds were reduced to insignificant levels.