Bright Ideas in Green Energy
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Bright Ideas in Green Energy

Professor Greta Patzke explains how she is attempting to solve the world's energy problems by finding a way to produce truly clean energy from sustainable sources.

Professor Patzke, your research is seeking to solve the world’s energy problem. Will this require significant restrictions on our lifestyle?

No. I want us to be able to maintain the current level of civilization, but without jeopardizing the earth’s ecosystems and the ecological balance. My goal is to develop a technology that will enable us to produce truly clean energy from sustainable sources.

How do you propose to achieve that?

With the help of artificial photosynthesis, using sunlight to produce hydrogen through the process of water splitting. Figuratively speaking, we are looking for a magic powder that can be sprinkled onto water – so that when the water is exposed to the sun, it produces hydrogen and oxygen.

Photosynthesis makes it possible for plants to use solar energy. Are you trying to imitate a process that has existed in nature for millions of years?

You could put it that way. But you can’t simply take a natural process and transplant it into the laboratory. That would be like removing a person’s eye and implanting it into a robot in the hope that the robot would then be able to see. It doesn’t work that way. We are trying to develop a technology that is simple, robust and inexpensive, as well as more efficient than natural photosynthesis.

My goal is to develop a technology that will enable us to produce truly clean energy from sustainable sources.

Artificial photosynthesis is considered one of the most difficult challenges in chemistry. Why?

Water is a very stable compound, and that's a good thing. Just imagine going to the beach on vacation, and having the water in the ocean split when the sun shines on it. That would be terrible. For splitting to take place, you need a catalyst, and that's what we're looking for. Actually, we need two – one for oxygen and one for hydrogen. My research focuses on oxygen catalysis. That's the more difficult challenge.

How does such a catalyst function?

We have several different approaches. For the most part we're working with cobalt. Last summer we published a paper about a cobalt complex, a unique molecule that appears to combine all of the desired characteristics. Now we want to study it further. I should point out that the basic criteria for the catalytic process are not yet fully understood. Sometimes it seems as if we're building 100 cars, and two of them are of excellent quality, 48 aren't so good, and 50 are junk – and we don't know why.

So it takes luck?

At any rate, there is always an element of chance. The processes are so complex that it's impossible to monitor all of the variables at the same time.

Do I understand you correctly that it will be not just years but decades before it will actually be possible to use artificial photosynthesis?

If we find a good catalyst, it could go quickly. If not, it may take a while.

We are trying to develop a technology that is simple, robust and inexpensive, as well as more efficient than natural photosynthesis.

Artificial photosynthesis will open up enormous business opportunities – why aren't companies conducting research in this area?

I'm sure the industrial sector will jump in when it sees a major breakthrough. Right now, however, we're still in the realm of basic research.

If we were already at the point where your method could be used to produce hydrogen in a clean and economical manner, what would we do with it?

With a fuel cell, hydrogen can be used to produce electricity. Or it can be used to produce artificial fuels, such as synthetic gasoline. The process is called Fischer-Tropsch Synthesis, and it was already used during World War II.

We already have photovoltaic cells for solar energy. So why do we need artificial photosynthesis?

Photovoltaics is a sophisticated, fascinating technology, but it has a significant drawback: It produces electricity – in order to store the energy, you need a grid.

And that's not the case with artificial photosynthesis?

No, with artificial photosynthesis, you have the hydrogen to work with. This clean technology will definitely have a valuable role to play in places that lack a power grid. In general, moreover, we should avoid relying on a single technology, as we have done with oil and gas.

How did you end up conducting research in this area?

I started from the ground up, learning the basics of nanoparticles and chemical clusters. It was only when I was really up to speed that I said to myself: I want to give back to society. That meant working on future-relevant topics with practical applications. It wouldn't have been possible without a solid foundation of knowledge.