Water-soluble semiconductor nanorod crystals that allow for efficient light-driven hydrogen production.
- 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.
- Provides unique absorption properties, larger extinction coefficients, weaker concentration dependence, and enhanced photostability compared to commonly-used molecular chromophores.
- Offers both efficient electron excitation and efficient photoreduction of the redox mediator into its active form.
With rising oil prices and energy costs, the need continues to grow for clean and renewable energy sources. In recent years, significant attention has been paid to the use of hydrogen-based fuel systems as an alternate energy source. Currently, the world hydrogen gas market is at $300 billion annually and is continuing to grow at more than 10% per year. Hydrogen-based systems have the potential to reduce local pollution and carbon emissions because hydrogen fuel cells emit clean exhaust. However, as long as the majority of hydrogen continues to be produced by burning fossil fuels, some pollution is emitted by the hydrogen manufacturing process. There is a need for a better hydrogen production process.
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.
Nanorods have been produced and improve the solar-to-fuel conversion process in a model system.