Development of parallelized, colorimetric hydrogen detection films for photo generation of hydrogen from bioavailable oxygenates | Poster Board #4082

Photocatalytic hydrogen evolution reactions have the potential to sustainably provide the planet with a source of renewable energy. These systems can be studied colorimetrically using hydrogen detection films that have been implemented on home-built photoreactors capable of running 108 experiments at once. Films are made using a 0.05% (w/w) platinum impregnated tungsten oxide powder that is surface-treated and suspended in polydimethylsiloxane. Images of the films taken over the course of an experiment are fed through an image processing program that correlates the normalized darkness of the films to the mole fraction of hydrogen generated in the reaction vials. These measurements are converted to a concentration of hydrogen in micromoles, capable of detecting between 5 - 97 μmols. This approach has been used to study the oxidation of biorenewable alcohols as the electron/proton source for the photogeneration of hydrogen. The system utilizes a molecular iridium photosensitizer (PS), an in situ synthesized Pd-containing colloid catalyst, and a redox shuttle (RS). Bioavailable donors including an array of alcohols, sugars, and starches were screened and optimal reaction conditions for the formation of hydrogen were identified for each species. The resulting reaction conditions were used to screen 96 uniquely structured iridium organometallic complexes as photocatalysts and for a set of structurally diverse RSs. Nanoparticle characterization for select candidates by transmission electron microscopy and X-ray photoelectron spectroscopy and identification and quantification of the donors’ oxidation products via 1H NMR were undertaken.