 Oh hey Medor. Hey Michael. How's it going? It's going all right Say Medor. I've been thinking a lot about saving the world lately. Really? Me too. What did you have in mind? You know energy is a huge issue. I was wondering what your thoughts are on the One of the biggest problems facing energy in the world today. Well, I think there's a lot of great technology for generation But I think unless there's a good way to store that energy They're going to have a hard time scaling that up and it'll be even better if you could store that energy in synthetic fuels instead You know water is abundant and you can split water into hydrogen and you can also convert carbon dioxide and carbon monoxide So if you think we can do this with solar energy, absolutely There's a field called solar water splitting where they use these things called photo electrochemical cells to convert solar energy into hydrogen fuel How did those work? Let me show you. So these are photo electrochemical cells or PECs And the way they work is they absorb sunlight in the semiconductor and they generate an electron in a hole The hole goes through the material to the solution where it oxidizes water to create oxygen gas The electron goes through an external circuit into the metal cathode and then to the solution where it reduces the proton to form hydrogen gas Oh these I hear it's challenging to engineer PECs that are inexpensive efficient and stable any idea how to make them better Well, so conventional wisdom says that these should operate at room temperature, but I'm not convinced that this is the only approach I think heating these up could really help. That sounds like a lot of energy True, so you can actually get all this heat for free because solar concentrators have been shown to get your cells above 400 degrees Celsius But why heat them up in the first place? It's a good question So kinetically your reactions get a lot faster as you increase temperature and thermodynamically it actually takes less energy to split water But doesn't your photovoltaic decrease? For solar cells, yes But for PECs there are all these other processes that either become easier or faster at high temperature And we've actually seen in lab that materials like iron oxide or bismuth vanavate for them the benefits actually outweigh the costs Check out this plot So here we have a plot for iron oxide and what you can see is by increasing the temperature from just 10 degrees to 70 degrees We see an increase in the photo current of over 50 percent That's great But how high can we go if we heat it up much more the water will evaporate and the PEC won't work anymore Exactly, that's why you need a whole different device design to make this work Here's how that could look so the main idea here is the same as it was for a liquid PEC But instead of having water to conducting your ions you have a solid electrolyte instead these can only conduct at elevated temperature So they're perfect for this application cool So how high can this efficiency get for these devices? Well, my colleagues have done some simulations on this device design and as you can see here They found that you can reach 15% Solar to hydrogen efficiency if you operate between 350 to 500 degrees Celsius So now we're at elevated temperatures and we have a solid gas interface We will need different catalysts that are stable under these conditions like those found in our work on solid oxide fuel cells We're very interested in the service of these catalysts, you know, this is the frontline of electrochemical activity However, the surface structure and composition came very greatly from what is found in the bulk So we use secret front radiation to understand these surfaces to design the high activity and good stability So with such incentive to go to elevated temperature and having a good fundamental understanding What we need now is to develop a new device platform for solar water splitting Well, that was the most productive three-minute chat I've ever had all right. Let's go save the world