Visible-Light-Responsive Catalyst Development for Volatile Organic Carbon Remediation

Photocatalysis is a process in which light energy is used to ‘activate’ oxidation/reduction reactions. Unmodified titanium dioxide (TiO2), a common photocatalyst, requires high-energy UV light for  activation due to its large band gap (3.2 eV). Modification of TiO2 can reduce this band gap, leading to visible-light-responsive (VLR) photocatalysts. These catalysts can utilize solar and/or visible wavelength LED lamps as an activation source, replacing mercury-containing UV lamps, to create a “greener,” more energy-efficient means for air and water revitalization. Recently, KSC developed several VLR catalysts that, on preliminary evaluation, possessed high catalytic activity within the visible spectrum; these samples out-performed existing commercial VLR catalysts.Project Goals:Develop rugged reactor test bed for catalyst testing with exchangeable light sources.Optimize KSC-developed VLR-catalysts to treat recalcitrant trace contaminants found in closed-loop air systems such as ISS.Advance TRL to align with AES goals for FY16/17 scale-up testing. The knowledge gained from this research will inform continued advancements in trace contaminant control. The research will provide insight on the ability to utilize visible-light-induced photocatalysis for the safe removal of volatile organic chemicals. This project will advance a much needed remediation technology, throught the following tasks:Task 1: Development of reactor test bed and LED array.Modification and development of a current catalyst test bed including rugged reactor design and in-line monitoring of contaminants to determine photocatalytic activity.Development of a visible wavelength LED array for comparison of light source choice in experiments.Task 2: Optimization and testing of top-performing catalysts. Optimization of catalyst formula and immobilization techniques for catalyst evaluation.Completion of catalyst evaluation including ability to degrade multiple challenge contaminants, catalyst lifetime, etc.Evaluation of effective light sources for photocatalytic work to achieve independence from Hg-containing lamps.Task 3: Physical characterization of catalysts. Analysis of physical characteristics including, but not limited to, XPS, diffuse reflectance, BET surface area, SEM, etc.Task 4: Evaluation of technology for validation in relevant environments such as HISEAS or similar.