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Matthias Driess

Matthias Driess

Professor of Inorganic Chemistry, Technische Universität Berlin, Coordinator of the Cluster of Excellence “Unifying Concepts in Catalysis”, Berlin; Team leader of the Research Unit “Inorganic and Analytical Chemistry” at the Department of Chemistry,

Any form of energy may be transformed into another form, but the total energy always remains the same, says the law of thermodynamics – what it doesn’t tell us is how can we use this principle to our advantage. In a time of ever-decreasing natural resources, posing such a question of crucial importance for our planet – for currently, transforming energy entails threats to our environment, CO2 emissions and nuclear waste disposals being the most severe.     Matthias Driess (1961), a philosopher and a scientist by training, seeks an answer by transforming sunlight into hydrogen. After working at the universities of Heidelberg and Bochum, Driess now serves as coordinator at “Unifying Concepts in Catalysis” (UniCat) in Berlin, the largest Cluster of Excellence project  funded by the German Research Foundation. If the experiments from scientists in the consortium are successful, they could contribute substantially to solve the problems inherent in world-wide energy supply: political dependency, CO2 emissions and environmental damage – thus realising what the Greek “energeia” means: activity.

Breaking the Wall of Limited Resources. What Catalysis Can Do to Save Energy and Create Materials.

Transcription

My family suffered from the division of Germany. Seeing the wall come down left me speechless.

Welcome everybody. I should admit first that I am really touched to be here, and I am keeping the role of somebody who is privileged to talk to you. I take this opportunity to remember, at least the moment as I recognised the wall came down. This was about things you haven’t expected. But, this is for a scientist not very difficult to understand and to live with that, and then not only that, but to take lessons from that. So, we are talking about in-depth changes: in-depth changes are always a collective endeavour. I should always mention that, of course, it is maybe a triviality to you, but walls are always connected to lessons for mankind. That is that it shows the long, long way to civilisation.

You may ask yourself: are we already civilised? What is the definition of civilisation? The way to civilisation is two-fold- at least two-fold. I make it simple. It is first the pressure not to rest. And the second thing is that we don’t know for what all? It doesn’t explain, but it says that it is the way that we have to go. I am not talking about religion, but it could have been also independent of religion, that with or without blood of humans we go further.

What seems to be always the prerequisite of doing so, in other words, what are the pattern of pursuit? This is difficult to be described. However, I take the risk to make use of a picture for that. I should put it in an allegory. The allegory is: what has the Chinese Wall and the President of the United States of America in common? Well, first of all, they are most visible, dunning witnesses of the stage of what we believe as civilisation. We have seen Presidents, which did it well. (Laughter in audience)

We learned this morning that this is kind of a perspective one takes to understand to put this in a, I should say, more simplified picture, however, we rely on that; we need this picture to rely on that. We also witness that we have examples- not only where a President went well, but also Presidents can do backwards. They could do it more difficult, and we are aware of drawbacks.

Now let me come to the subject, which is changes; changes need energy; changes need, that in particular, we have to take the burden for collective efforts. A collective effort means change and prosperity. And we all need that, of course, but changes aren’t free of charge! We have to do something for it. This seems odd in the first instance when you hear that. But, aren’t free of charge is very clear. The issue to do so is energy. We sometimes believe that energy is just getting out of the plug, but energy is everywhere. But, however, if you know once you have the energy, it has to be distributed, and it has to do with the order of orientation- what we expect. Energy is a network business which enables are daily live, the engine of our materials world, dreams and quality of life. We learned also this morning about health, food, and the key role of education to see through this complexity.

What is well known, and it is cited many times that energy is on the top, maybe on the top, of the ten main global problems of mankind. Which means, if you are thinking about how to maintain the source of energy, it has some impact on other issues we are talking about everyday.

Ok, this can also be said in a Sunday speech of a priest; everybody can say that. The question is: how to change or what type of energy you need. It is clear; it is all over in town that the total energy on our planet is limited with concurrently drastic increasing population (2009: 6.8 billions). There are a lot of political things behind that discussion, but there is a truth, a solid truth, behind that, which is: we are certainly running out of fossils. This is not a fairytale! That is true! Nobody can really imagine how the scenario would like if you just wait until it is over. So, of course, the responsibility, this was also a term you heard today. We have to go further and develop ways of using solar energy. That is an unavoidable change event.

Well, since we are talking about the universe and the border or the walls of the universe, the only thing is we are connected to an unimportant part of the universe, which has a sun. The sun provides us with a lot of energy, and of course, burning all the fuels we caused a lot of problems: CO2 climate change and all that. So what about the vision, which is clear we have to find answers to manage artificial photosynthesis. You can find articles in literature where people promise to do so and so on, but it turns out that this is very difficult to do. However, a start for changing is, for sure, that if you would be able to have an energy source that is indefinite! It is like making energy from an indefinite source. We should keep in mind that the latter demand is always connected to materials: Suitable materials are indispensible for energy conversion from sunlight into the common forms of energy (harmless fuels,  chemical energy storage).

The materials that we are talking about, and we would like to make more use of, is hydrogen. As a history for hydrogen, hydrogen is a powerful component. It is a powerful chemical, and you all know that the fate of hydrogen power had some meaning to history.

I would like to do an experiment in front of you to show you that it is also a part of civilisation to be able to use the hydrogen appropriately. As you know, hydrogen is a light gas, and it can be easily burned- which I will demonstrate in the experiment. The privileged first rows: please open the mouth to make sure that the pressure balance is going well.

So, as you can see, hydrogen by itself is an energy-rich compound. People learned how to civilise, but sometimes, as I showed you in this second graph, some drawbacks could happen. So, I need the other balloon with hydrogen.  Some drawbacks, so it starts, the scientific methodology, to learn, how to use, how to make use of hydrogen in an appropriate way to get a little better control. As you all know, this is really to celebrate the fall of the Berlin Wall- you can’t do better by using Knallgas.

But you see, once you have done this experiment, you ask yourself: you are a chemist; you might be suspicious to be a distrusted person: can you do even larger? For that I have planned originally to invite our Chancellor to assist me, and she knew that already so she left. So, I do it myself without saying good-bye, because then nothing happened, because there are other gases known, which do this typical light behaviour as hydrogen, but they are non flammable like the beautiful chemical element helium. This is kind of a lesson taken by scientific methodology.

But back to the subject, before and after, now we would like to learn how to tame hydrogen and its energy by taking advantage of chemical technology. This is based on a very well developed method that is known for quite a long time, which is conventional fuel cell. For the conventional fuel cell, you take hydrogen gas, the hydrogen splits on a platinum surface in the one part into protons and electrons, and the electrons move to the other part of the cell where they are captured by oxygen to give oxide anions thereby producing electric power. Overall, the mass balance is that conversion of hydrogen and oxygen in a fuel cell produces water and electric energy. With the latter electric energy one can light a bulb or so. For splitting hydrogen in protons and electrons, you need platinum and then something else to set up. This enables you to use hydrogen in a well-behaved manner. However, as we heard also this morning, we have a serious problem if everybody would like to use that in different applications: we are running out of platinum, because platinum is rare and thus relatively expensive and belongs to the class of precious metals like silver and gold.

This is the Berlin answer to the crisis of the S-Bahn. (Laughter in audience) We take advantage of the reverse process of conversion of hydrogen and oxygen to water and electric energy can be managed through so-called electrolysis of water (depleting water). The electric power stems from a solar cell. Thereby we are able to produce hydrogen for a fuel cell and powering a car with it. You can do it yourself, start up to make a hydrogen car, and the basis is- this is of course a joint project- you have solar electricity; you are depleting water, and the water is then used in a fuel cell in order to make the car moving.

I do that here. We have a tank; we already exposed this to light. So, we have a tank of hydrogen and oxygen. If I connect this here, it moves (not really fast- I told you it is pretty much like the S-Bahn in Berlin (Laughter in audience- applause). You are invited to come and to enjoy after my talk this experiment.

So, we know that we can do that, and there are many departments that are able to do so. Now back to the question: how can we produce a large amount of hydrogen gas, because hydrogen gas is needed in a huge amount! We are talking about 500 billion cubic metres per year. That means that you would have to cover the whole world with this appropriate equipment to do so. The question is: it is difficult, however, if you never start, you will never be there. You will never win.

This is the subject we are talking about in Berlin, and we are doing in Berlin, which is catalysis research. There are different ways where you can capture energy to split water into hydrogen and oxygen, and for that you have this so-called married broker, the catalyst, which is the mediator to split water into the components: hydrogen and oxygen.

We do that relatively successfully in Berlin by taking two approaches. The first one is a biological approach. You will see that you can replace platinum by the trick nature developed already. You are taking enzymes, which are capable to do that, and the other one is the old dream, make it directly photocatalysis: splitting of water.

Catalysis, of course, is the (mega) international connection network. This is also the case for Germany. We are, of course, not the only one doing that, but in particular for the North German region: Berlin, Potsdam, and Rostock are very strong in this cross-disciplinary field.

Now, in our cluster of excellence named “Unifying Concepts in Catalysis” which is the largest cluster in the excellence initiative by itself, we are developing how to unify the different strategies and strengths in heterogeneous, homogeneous and bio-catalysis and to use them in order to enable a much higher materials and energy efficiency. We do that by a consortium, which consists of four universities and two Max Planck Institutes. You can see a large number of people who are necessary to make this effort.

Now our first example, hydrogen production: what you do basically is learning from nature. It is clear from the photosystems of plants and bacterias, which contain big molecular machineries, that nature is capable in managing energy transfer from sunlight to produce electrons. The electrons can be used to convert CO2 into value-added products like sugar. This is the key process for feeding of mankind, the origin of our food chain.

Imagine you have an artificial enzyme, which is also quite interesting. You can combine enzyme functions. You have a combination where enzymes that produce hydrogen, and if you fuse (that is what we do) this enzyme to the photosystem, we are capable to produce hydrogen by an artificial enzyme system, which consists of parts of the machinery of the photosystem as sunlight antenna-like system and the electrons thereof are transferred to the hydrogenase enzyme which is capable to produce hydrogen from protons and electrons.

If I click here a little bit, you see you can enable, and that is really what is going on, you are capable to couple the two relatively complex systems. If you do so, you can replace platinum. You are using the components for the hydrogen production on one side, and for the oxygen production on the other side- all is based on biological systems without any precious or poisonous metal. By that, you can do the same thing, the same production of energy, but now without platinum. I would say that is really an interesting break-through in that field. If you are interested in seeing that, we have prepared the experiments here; you can see it as it is by yourself.

The last one is very short. Now you can, of course, the dream is hydrogen from water directly. We should keep in mind it is very, very difficult, very demanding. Natural photosynthesis is lousy, but it is huge. Solar reactors are much more efficient; electrolysis is much more efficient. So, we have a benchmark system, which is based on 14% efficiency. We would like to combine a system that could do that.

We do this by splitting the two reactions (boom). We can do it by splitting the two reactions, and we do this by the combination of completely new materials. This is the way that chemistry is doing this. We can use completely new materials, which are metal-free or metal-oxide based. The key concept is chemical synthesis: The chemist’s creativity and art of making new compounds which combine different properties in it self. If you do that on a rational basis, we can in fact have materials, which are currently unknown or even believed not to exist. This is, for instance, the case for abundant (cheap) metal oxides which can serve as transparent conducting oxides and replace expensive metals in catalysis.

By choosing the right material, one can, of course, make use of the whole spectrum of sunlight for harvesting sun energy; the whole spectrum of the sunlight is where you capture also infrared and all visible components, for doing that more efficiently.

That is about it- what I would like to tell you. You saw my assistant. This was, of course, something we appointed already. It is all based on composition. I would like to thank all of you for your attention, and, of course, the German tax payers. They did a lot. Thank you very much.

 

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