In the process of solar-to-fuel conversion it is very difficult to simultaneously accumulate multiple excited electrons and suppress charge recombination (e.g. when an excited electron relaxes). Methylviologen can be used as a redox mediator that effectively mediates multi-electron photocatalytic reactions such as hydrogen production and carbon dioxide fixation from sunlight. Improvement of the light-driven photoreduction of methylviologen can result in more efficient solar-to-fuel conversion. Emory researchers have developed a nanorod that rapidly recharges the photoreduction of methylviologen with nearly 100% efficiency. The cadmium sulfide nanorod contains a cadmium selenide quantum dot which when combined more efficiently enhances solar-driven electrochemistry compared to using the rod or dot alone. With the addition of platinum nanoparticles these nanostructures can be used to transform water into hydrogen gas allowing for the efficient and clean production of hydrogen for use as an alternate energy source. Developmental Stage: Nanorods have been produced and improve the solar-to-fuel conversion process in a model system. Application: Water-soluble semiconductor nanorod crystals that allow for efficient light-driven hydrogen production.
1) Provides almost 100% quantum efficiency for photoreduction of a redox mediator during solar-to-fuel conversion for use in batteries fuel cells and other energy sources. 2) Provides unique absorption properties larger extinction coefficients weaker concentration dependence and enhanced photostability compared to commonly-used molecular chromophores. 3) Offers both efficient electron excitation and efficient photoreduction of the redox mediator into its active form.