Science

Artificial Photosynthesis at NCSU

• Fascinating
• Relevant
• Ingenious

Solar energy capture and use is one of the most important scientific challenge for our generation, and will impact our world for generations to come.

Update: Thanks to everybody who has contributed to this project - I'm ecstatic that it is a success.  We are not yet done, though.  We will use the additional amounts generated from this proposal for the purchase of an additional cell and other electrical goodies (wires, connectors, additional electrodes) to help us perform the experiments described below. 

Any amount helps!

When most people think of solar energy, they think of the black solar panels on a roof. That technology (photovoltaics), creates electricity - which can only be used the instant you make it. In order for solar energy to be used on a wider scale, we need a way to store that energy for use anytime -- today, tonight, or even years from now.

When thinking of storing electrical energy, you probably imagine the batteries in your laptop, phone, or flashlight. For those of us lugging around a laptop to and from work every day, you know that batteries are heavy for how much power they store. This ultimately limits their use, particularly in transportation, where every pound lowers the efficiency for getting from point A to point B. So, Tesla motors aside, a more “power dense” way to store solar energy is desirable.

Fortunately, we already know and use a energy dense power source – liquid fuels such as gasoline. The trick then is capturing solar energy and converting it into such a liquid fuel source. Plants accomplish this using photosynthesis, converting solar energy into power-dense sugars. Today this is exploited, albeit indirectly, with biofuels such as bio-deisel. What the world needs is a way to bypass biological systems, and learn how to create an technological solar-to-fuel system (artificial photosynthesis).

In order to accomplish this, four things must be realized:
1) absorb the energy of the light,
2) transfer this energy to a catalyst for making fuel,
3) have the catalyst make the fuel using the energy, and
4) capture the fuel for use.

Our project is helping us get halfway there by focusing on the first two steps.

Requested equipment:

In order for us to understand how to capture and transfer the energy from light into catalysts, we need to be able to measure how much light is absorbed by our molecules, while at the same time monitoring the overall energy of the system. We do this using "spectroelectrochemistry," where an aborption spectrum (how much light is absorbed at each wavelength) is measured while the potential energy is observed with electrochemistry. In order to do this, we have several specialized instruments that work together to collect both sets of data at once.
This crowdsourcing request is to purchase a cell and electrode where the reactions can take place. As shown in picture 2 above, light goes through the cell and the mesh electrode where the electrochemical potential of the system is altered. The new molecules that are created at the electrode can then be observed. We use this information to design the next set of molecules to synthesize, as well as understand if the molecules we make have the required properties for artificial photosynthesis.

The cost for this particular cell and electrode is $500. The NCSU Dept. of Chemistry has committed a "start-up" dollar-for-dollar match for up to $500, so if we're fully funded we'll be able to stretch your dollar(s) and allow for two of my students to work with these cells.

Technical information about our work

The group focuses on making new molecules that absorb light through a "metal-to-metal charge transfer transition." What is metal-to-metal charge transfer you may ask? Briefly, an electron gets transferred from one metal atom to another nearby metal atom when light hits the molecule (see picture 3 above where light is absorbed, transferring an electron from molybdenum (Mo) to titanium (Ti), creating a negatively charget titanium atom and a positively charged molybdenum atom). We hope to use these systems to capture the energy of the transferred electron to drive artificial photosynthesis. The spectroelectrochemical cell will help us learn how to do that.

The group currently consists of myself, 2 graduate students, 1 postdoctoral researcher, and 4 undergraduate students. Since we're a new laboratory, we are still putting together all of the equipment and supplies necessary to achieve everything we want to do, especially for the projects that the undergraduates are working on. This accessory will allow us to better use our existing instrumentation for my undergraduate researchers.