Science in the Triangle

Photon waves. (Wiki Commons)

The search for clean energy technologies is sparking a renewed effort to create fuels from sunlight-driven chemical reactions. Solar fuel technologies exist today but chemists across the nation are trying to figure out how to increase the efficiency of the reactions and create the next generation of photovoltaics.

About 100 faculty, students and visiting scientists gathered at the Univ. of North Carolina-Chapel Hill campus on Thursday to discuss advances in solar fuels research.

The event, organized by the Solar Energy Research Center, drew speakers from Johns Hopkins University, Cornell University, and the National Renewable Energy Laboratory. SERC itself is a consortium of UNC-CH, Duke, N.C. State University, N.C. Central University with RTI in Research Triangle Park.

UNC chemistry professor Tom Meyer, who is also the SERC director, said the group is a great example of the “new way of doing science” and bringing university research into collaboration with industry. Thursday’s gathering kicked off SERC’s second annual solar energy fuels conference, “Solar Fuels and Energy Storage: The Unmet Needs.”

Thursday and Friday were highly technical talks describing chemical mechanisms and applications that are advancing the field of solar-driven chemical energy. A public outreach component of the conference will take place 5 p.m. – 9 p.m. Friday at UNC’s Friday Center. At the outreach event, Meyer and several other speakers will talk with interested members of the public about the future, and the challenges, of creating solar-driven chemical fuels for applications in transportation and industrial-scaled energy distribution.

During the technical talks on Thursday, Gerald Meyer of Johns Hopkins University presented work detailing advances in molecular excited states showing light-induced electron transfers between molecules. In one example, he described a light-driven bonding reaction between iodide atoms and said the work could be a model for light-driven bonding reactions involving oxygen. Researchers like Meyer are experimenting with designing molecules that can be attached to a titanium dioxide substrate in order to create a reaction that will siphon off electrons after a photon of light strikes the material. Called dye-sensitive solar cells, this approach is proven to work but scientists are wrestling with creating a designer organic molecule that will yield higher efficiencies.

John Miller of JME, Inc. spoke about the future of bulk energy storage, citing research into how to increase the storage capabilities of electrochemical capacitors. He noted that maximum storage ability in these devices had increased “nine orders of magnitude” in his lifetime. The best capacitors consist of an asymmetrical electrodes placed in an electrolyte solution. The surface area of the electrodes is the limiting factor to increasing levels of energy storage, he said. The asymmetrical systems have disproportionately long discharge capabilities relative to their charging time, he said. The capacitors could be used in the future to store energy produced from utilities during non-peak hours at night, then be discharged into the electrical grid during peak hours – contributing to regularizing energy production. Currently, the largest units can discharge 20 watt hours per kilogram over a five-hour period.

Héctor Abruña, from Cornell University, spoke about electrocatalytic fuel cells and new applications in spectroscopsy to characterize the interface of nanoparticle reactions. He focused on describing the crystal structure of “ordered intermetallics” such as nanoparticle blends between platinum and lead or platinum and ruthenium, and how to quantify the electrochemical performance of these materials using scanning transmission electron microscopy and transmission electron microscopy. He described a new application in imaging where his lab rotated the imaging device around an ordered intermetallic group of nanoparticles to better understand how they were reacting in three-dimensions and over time.

There were many other talks, and the full listing can be found here.