Session VI: Electrified Synthesis of Molecules; Closing Remarks with Ralph Amos, CEO of CAA

welcome back congratulations we made it to the last session of the day so thank you and um we were just remarking backstage there have been so many Fantastic questions asked today and we know that we didn't get to them all and I could just see them going up in the queue and go oh we don't have time so we're going to see if we can follow

up um after today and see if those questions can be answered in some way so look for your email for that okay so we are now at on slido we're at Caltech 6 is the event code and it is for electrified synthesis of molecules it's our chance to learn how Caltech is leading the development of renewable energy Dr Carthage men theorem is Professor of chemistry and

biochemistry and a William H hurt scholar he earned his PhD in 2015 from UC Berkeley he Leads Here the man theorem lab which studies the development of heterogeneous Electro catalysts For the synthesis and functionalization of organic molecules using carbon dioxide nitrogen water and renewable electricity carthage's research has been recognized with numerous Awards including the National Science foundation's career award doe early early career award Sloan research

Fellowship 3M non-tenured faculty Award American Institute chemical Engineers 35 under 35 so so many more so what are the new technologies that Advance Renewable Power Carthage men theorem was going to tell us right now for our next session welcome last session of the day welcome thank you all right well thank you all for coming out I'll be telling you all today about uh what it'll take

to Electrify the synthesis of molecules in our motivation here really is that if we were to achieve this electrification of chemical synthesis that it could help Drive the decarbonization of the manufacturing of the physical world so if we look out there on caltech's campus you look for instance at this artificial turf field there is a huge carbon footprint that goes into manufacturing the fibers that are

part of that artificial turf even for the seat that you're sitting in right now there is a carbon footprint behind its manufacturing literally every material the Plastics the fibers the fertilizers used to grow your Foods they all have a carbon footprint behind them and we're going to talk today about how we might conceivably Drive the decarbonization of that physical world so we can look at this

problem quantitatively this plot shows the carbon footprint of the top 18 commodity chemicals as a function of their production volume and you'll see immediately that there is one chemical ammonia which has such a large carbon footprint that it actually has its own y-axis and if we were to have plotted everything on the same y-axis ammonia would be up top and everything else would be compressed down

at the bottom so it is essential that if we are serious about driving the decarbonization of chemical manufacturing that we have to do something about ammonia but on top of that if we do want to achieve deep decarbonization of chemical manufacturing then we will also have to do something about all these other chemicals shown here things like ethylene propylene methanol btx and ethylene oxide so if

we want to drive this decarbonization of chemical manufacturing then we should start by putting out a paradigm a paradigm that could guide our journey through this decarbonization and so I showed three conventional paradigms for chemical synthesis here first on the far left hand side we have biosynthesis this is how nature synthesizes a particular molecule so if we were to apply this definition for instance to ammonia

that would be a nitrogenase an enzyme which can take nitrogen water with the power of ATP to be able to make ammonia on the far right hand side we have total synthesis this is the desire to make a molecule beginning with anything that is simple and commercially available and so if we were to stretch this definition a bit for a molecule that is as simple as

ammonia that would mean the Haber Bosch process that's how we make ammonia today we start with methane and water and nitrogen and we commercially combine those to be able to make ammonia what we're working on in my group is a way of being able to make this physical world to make these chemicals beginning with just three molecules so rather than using anything which is commercially available

we're using just CO2 nitrogen and water so these are three molecules which give us a source of four atoms that we can now stitch together to be able to make the physical world and we drive these reactions using renewable electrons that if we use the power of the Sun or wind to be able to drive these bond breaking and bond forming steps that we can do

chemical synthesis more sustainably than if it were driven by temperature and pressure these are the conventional variables or driving forces that are used in chemical synthesis so we can look at how we would implement this we're starting with nitrogen reducing it fixing it to be able to make ammonia taking CO2 converting it to be able to make Co and ethylene and then starting to combine these

first reduction products with additional chemistries like oxygen atom transfer to be able to make products like ethylene glycol ethylene oxide to make lactones and even amino acids so these are a few examples of the types of products that we're aspiring to make beginning with very simple and ubiquitous precursors so we'll get two examples today the first will be the desire to make ammonia beginning with nitrogen

to do that at room temperature and ambient pressure conditions that are very different from how we make ammonia today and then we'll look at this desire to convert olefins and water into epoxides that if we were to do this we could make epoxide synthesis much more sustainable than it is today so we'll focus in first on making ammonia so we can take inventory of the challenges

that ammonia synthesis faces today on this plot here we have dollars per ton of urea urea is a ammonia containing fertilizer and we have several countries here in sub-Saharan Africa Burkina Faso Cote devoir Ghana Mali Nigeria the Senegal and their price for urea as compared to the international average and one thing you'll see immediately here is that the price of fertilizers in these countries is two

to three times the international average now those fertilizers all cost about the same up until they're brought to Port it really doesn't matter where that vessel is going in the world through the oceans but it's that Journey from Port to where those fertilizers are ultimately used that can vary so much in cost depending on where you are in the world and in these countries in sub-Saharan

Africa Burkina Faso Cote d'Ivoire and others these are countries in which the money needed to make investments in infrastructure to make fertilizer distribution cheap it doesn't exist and this has been a long-standing challenge so these resources have not materialized for the necessary Investments that in turn means that fertilizer prices of course are higher there's lower fertilizer usage pork crop yields and that in turn is one

of the factors that contributes to severe malnutrition and sub-Saharan Africa so this is an important problem to solve we can look at how we make ammonia today and think about why that contributes to the problem that I'm describing here we start today with methane and water we combine those to make hydrogen so we're ripping hydrogens off of the carbons and off of the water as a

result the carbons and oxygens combine to make CO2 so we have a stoichiometric CO2 footprint that comes out of this reaction this is done at greater than 700 degrees Centigrade we then take that hydrogen we combine with nitrogen to make ammonia and we do this at 400 to 500 degrees centigrade and 150 to 250 bar of pressure so you'll see two immediate problems here the first

is that we have an enormous CO2 footprint and this is so large of course that it is part of why ammonia has the largest carbon footprint of any chemical that we manufacture today and the second problem is the harshness of conditions greater than 700 degrees C for this first step and 150 to 250 bar of pressure in the latter step and this means that this is

chemistry that you can't practice close to where it's needed you can't do it in a distributed fashion these conditions are sufficiently harsh that you have to do this at really large scales in an essentialized fashion and that's why there are a relatively small number of ammonia synthesis plants worldwide from which we distribute that ammonia and as a result we have a heavy Reliance on infrastructure for

Distributing ammonia and so if we were to dream about the characteristics that we would desire for a Next Generation method of making ammonia we would first wanted to eliminate the CO2 footprint and second we would want it to operate at more benign conditions at room temperature and ambient pressure that if we were to achieve that that ammonia could now be made closer to where it's needed

that we would no longer need to distribute it over long distances which contribute in some parts of the world to higher costs for that fertilizer and that's really the goal that we have in the work that my group is doing on ammonia synthesis I want to share a second source of motivation and this is really something that's emerged in just the last few years I'm sure

we're all familiar with the hydrogen economy the desire to be able to power certain parts of the world and our daily activities with hydrogen as a molecule for energy storage and to also use clean hydrogen and chemical Manufacturing so the problem with this Paradigm to use hydrogen as a method of conveying energy is that hydrogen doesn't really have a very high energy density so if we

start for instance with water and we split it and we make hydrogen moving that hydrogen around to where it's ultimately needed is really expensive and we can see that here in this table that the energy density of hydrogen at one bar is dressed 0.03 kilowatt hours per liter which is really low we can pressurize it going up to 700 bar which is again a really high

pressure and if we do that the energy density of that hydrogen increases to above one kilowatt hour per liter but that again is a really high pressure it takes so much energy to compress this hydrogen that you lose about 10 to 20 percent of the initial energy content that the hydrogen has so that gives you some idea of just how energy intensive even just that compression

is to get to a reasonable energy density and as a result this adds about 10 cents per kilowatt hour and you can reference to this to the cost of renewable solar or of wind typically around five cents per kilowatt hour sometimes even a little less this storage in hydrogen adds a lot of cost so if you're trying to take renewable electrons and put that energy into

a chemical carrier like hydrogen they're techno economically this just isn't viable yet and so what we can look at instead is filling this box with a secondary carrier we can take that hydrogen that we're making by splitting water and we can now associate that hydrogen with nitrogen to be able to make ammonia and this ammonia now we can transport at a much lower cost for reasons

that I'll describe in just a moment we can then dissociate that ammonia close to where it's needed making hydrogen releasing nitrogen which we can just vent into the atmosphere and this hydrogen then can be used in whatever terminal application was envisioned otherwise and so here ammonia becomes our dominant energy carrier and so we can look at this by the Numbers ammonia has an energy density of

three kilowatt hours per liter at just 10 bar so that of course is much higher than hydrogen which existed at only 700 bars so we see an immediate Advantage there in terms of energy density and on top of that the compression losses The energy needed to get to 10 bar is just two to three percent of the initial energy content of the hydro of the ammonia

so this is uh much more usable from a techno-economic perspective and the cost of transporting and storing that ammonia is just one cent per kilowatt hour so the Techno economics of this start to look better as well so two sources of motivation here then right one is fertilizers which I talked about in the last slide and the second is energy storage and this may seem a

little distant but there are many pilot projects that are being announced worldwide of any chemical carrier out there ammonia is getting the largest investment today relative to anything else that's been proposed out there so this is a big change that's happened in just the last couple years but there's still a lot of research to be done to actually enable the viability of ammonia as an energy

carrier at scale and that's exactly what we'll be talking about today so if you look at how ammonia is made today you all may I remember from two slides ago that I mentioned that pressure is important that you have to reach pressures of 200 to 250 bar to drive this conversion of nitrogen and hydrogen to ammonia and what we want to look at is if we

can replace that pressure with voltage instead that this could be a much more benign driving force to use to drive this chemical reaction so we'll focus in on this particular step of this process this color map here shows conversion which is a variable X that ranges from 0 to 1. anywhere the conversion is zero that means we are entirely at reactants just nitrogen and hydrogen and

if the conversion goes to one that means we have fully gone to ammonia as a product So based on this color map we'd want to be in regions that are red as opposed to those that are blue so here in this color map we have temperature on the x-axis and pressure on the y-axis and so looking at this we may decide to start at the origin

that the thermodynamics at that point look favorable however there is a kinetic challenge even though this reaction of nitrogen and hydrogen would go to ammonia if given eternity which is all that thermodynamics is telling us kinetically it doesn't work out and for that reason we're forced to increase the temperature up to about 500 degrees Centigrade at that point these bonds actually become labile the nitrogen triple

bond can be broken over a suitable Catalyst and it can reassociate with hydrogens to make ammonia the kinetics start to work out but you can see the problem based on this plot which tells us just the thermodynamic reality here which is that we have a very very small equilibrium conversion that sure the bonds are breaking and forming and that's all happening from a kinetic perspective but

we stop at a less than one percent single pass conversion if we are at 500 degrees Centigrade now the way we solve that is by pressurizing because this is a reaction in which we have a reduction in the number of moles pressurizing by Le chatelier's principle allows us to shift the equilibrium of this reaction to the right and so if we go up in pressure to

200 to 250 bar we can now get to an ever so slightly lighter shade of blue here where we have about a 15 single pass conversion and this is actually how we make all the world pneumonia today with a 15 single pass conversion so it's really a testament to engineering that after a century we have gotten this process to a place that we can feed the

world with fertilizers that are cheap enough even though the molecules passing through this reactor only have a 15 single pass conversion which is really really small and so we can consider instead to use voltage to recover conversion in the place of pressure this plot has the exact same x-axis we still have temperature but we've now placed voltage on the y-axis and you'll see a plot that

looks really different we could start for instance at 500 degrees Centigrade we can now apply a third of a volt going up and we would reach a region which is deep red In Color near unit conversion greater than 99 conversion of nitrogen and hydrogen to ammonia which with just a third of a volt and I remember doing this calculation about five years ago and what we

recognized here is of course that this is less than the voltage of a double A battery right a double A battery is 1.5 volts with a third of a volt you can shift this reaction you can do far more than you could do with thousands of bar of pressure with just a really tiny voltage and that really for us has been extraordinarily motivating to try to

figure out ways of using voltage to drive chemical reactions that this at its very core is why we want to Electrify chemical synthesis because there are things you can do with voltage the temperature and pressure could really just never do now it turns out that voltage helps not just the thermodynamics it helps the kinetics as well so you can in fact come back down in temperature

even down to room temperature and drive this reaction with voltage alone to help the thermodynamics and the kinetics of this process so you may look at this and think well should we Electrify Every chemical reaction if this looks good for ammonia should Every chemical reaction out there be driven with electrons instead of temperature and pressure and the answer to that I think is actually no there

are some reactions like the one that I'm showing here to make nitrogen and hydrogen and ammonia that benefits from electrification there are other reactions though that are better driven with temperature and pressure and it all comes down to the down to their thermodynamics we've got we've actually published a paper last year or 2021 sorry so two years ago now that shows how just based on thermodynamics

you can actually determine whether a given chemical reaction should be driven with voltage temperature or pressure and so one can obtain very clear guidance to know a road map for the next 20 years as to what our targets should actually be so what I told you about ammonia on the previous slide that it benefits from electrification May give you the impression that this should be possible

already but it turns out that even though the theory of what I'm showing on the previous slide looks promising that there are still challenges in developing catalysts that have suitable rates for driving this reaction and what I want to share with you today is a process whereby you can use lithium metal to actually drive this reactivity and so here starting with lithium metal one can react

with nitrogen that lithium metal reacting with nitrogen can spontaneously make lithium nitride this is one of the really special things about lithium metal that if you expose it to nitrogen gas it will spontaneously break the nitrogen triple bond that even though that triple bond is so strong that in the presence of lithium metal it dissociates and it makes a solid-state form of nitrogen here li3n that

lithium nitride can then be protonated by a proton donor that I keep generic for now that in turn leads to exchange of the lithium ions with protons that in turn makes ammonia as a product lithium ions which are discharged into solution and those lithium ions can then be plated so that we return to lithium metal and can continue around this cycle so there are actually been

a few demonstrations demonstrations of this so we can look back about five years ago there was a demonstration that showed how you could take lithium metal that's plated out of a lithium chloride lithium hydroxide bath operating at 400 to 500 Centigrade you could take that lithium metal you could cut it up and put it into a beaker you could introduce nitrogen gas you could make lithium

nitride you could then introduce water as your proton donor you'd make ammonia you could boil off the ammonia and water you'd leave behind lithium hydroxide and you could dump that back into the first bath and you could continue around this cycle they demonstrated a greater than 80 percent faradayic efficiency for making nitrogen and ammonia and Faraday efficiency is defined as the fraction of electrons that go

toward your desired reaction so if it's 80 then 80 percent of the electrons went towards making nitrogen into ammonia so this is pretty good from an electron based selectivity perspective but we can probably all agree that we're not going to feed the world with the reaction that involves solids that solids handling is really challenging and we have macroscopic chunks of lithium metal here which we really

want to avoid right we know that there's a safety hazard in having large pieces of lithium Metals so even though this is a good proof of concept there are a lot of issues with this implementation what we've been interested in instead is a report from 1994 there was a group in Japan that actually demonstrated this ability to put two wires into a solution that one of

these wires a copper wire you could actually plate lithium ions at to make lithium metal that lithium metal could then react with nitrogen gas that you're bubbling through making lithium nitride they can then react with a proton donor ethanol to make the lithium nitride into ammonia and all that could happen in a single Beaker so we were really intrigued by this report this isolated report that

demonstrated that a one-pot reaction could perhaps be done the issue here was that the Faraday efficiency was really low it was just eight percent so a very small number of electrons just eight percent of the electrons were going to the right place the rest were going towards undesired reactions in this process and the rate was just 0.55 nanomoles per centimeter squared electrode area per second which

we can probably all agree is really small one so this was a pretty humble starting point in terms of electron based cell activities and rates from where we wanted to try to make improvements so as we started working on this chemistry the the first thing that we recognized was that we needed to make a more robust reactor architecture so we went from having two tiny wires

dangling in a beaker to something that was more scalable here we have a copper foil cathode on the left side and a platinum foil anode on the right side we have a separator which just helps to keep the two compartments here apart from each other we have an electrolyte that is lithium tetraforaborate with tetrahydrofuran still with ethanol as the proton donor and we in this cell

are bubbling through nitrogen gas that nitrogen gas is reacting with lithium metal that's deposited on the surface of the copper cathode these are really small amounts of lithium in inventory so the safety hazard is really eliminated and what we found is that it is this journey of nitrogen from the bubble to the surface of the electrode that's limiting it's not actually the reaction this this breaking

of the nitrogen triple bond that's the hard step it is the physical movement or transport of nitrogen gas from the bubble to the surface of the electrode that was the step that was limiting the rate of this reaction and so that's really the problem that we set out to solve it at the very beginning what we drew up on a whiteboard was a reactor that looked

like this that we could start with a that we could Implement a gas diffusion electrode on both sides of this reactor that a gas diffusion electrode which is just a porous medium that facilitates contacting could allow us to bring together nitrogen gas with a liquid electrolyte with the solid phase here which is conducting the electrons so there are three different phases solid liquid and gas that

could all be brought together within this porous medium that we call a gas diffusion electrode and we reason that if this were implemented then both gas and liquid could meet each other at the solid surface so we would no longer have this journey of nitrogen gas from Bubble to surface of the electrode be limiting because the gas would have direct contact with the surface of the

electrode as shown here and so we implemented the stainless steel cloth as a means of driving this reaction so that's what we're using as a gas diffusion electrode and at the anode we did the exact same thing here we're oxidizing hydrogen and we're using a platinum Catalyst that's deposited on the surface so this was our first step towards trying to solve this transport limitation within this

reactor and what we found was that what would otherwise be a transport limited rate of less than 10 nanomoles per centimeter squared per second or even less than one nanomole per centimeter squared per second as shown in the previous report by cineto at all from Japan we can now reach 30 nanomoles per centimeter squared per second so we can see immediately that we've actually alleviated this

transport limitation we can now Drive much faster rates of interfacial reaction just by implementing this very simple method of contacting gas and liquid at the surface of the electrode the second benefit of this is not just that the rates are higher it's that the Faraday efficiencies are now also much larger so what was just eight percent before for this one pot realization just by solving this

transport Problem by getting the nitrogen to where it needs to go in the reactor we can now get nearly half the electrons to go to the right place we have a faraday efficiency of nearly 50 percent Now by implementing the gas diffusion electrode so there are many fundamental puzzles in this chemistry we see here this ability to practically improve rates of reaction but we were stumped

in our lab as to why certain electrolyte compositions work well While others don't the essential question to us was why does ethanol work well why does tetrahydrofuran work well as a solvent why not use a different solvent like DMSO or why not use an ether a different type of ether as a solvent and so this for us was extremely hard to answer we tried hundreds of

experiments trying different solvents and different proton donors and putting up here a sampling of data showing the faradayic efficiency for different proton donors in this chemistry and honestly it really just couldn't make sense of this this looked about as random as could be we continue to make hypotheses we would do 10 more experiments we'd look at the data again we'd come up with a better hypothesis

and we would try again and we continue to March through finding no success whatsoever and explaining why protons certain time to owners and certain solvents worked well for this chemistry the final hypothesis that we made in this space that yielded a robust result was that it had to be what is called the solid electrolyte interphase that lithium metal is so reactive that if you take lithium

metal and expose it to any type of organic solvent that you will instantly decompose that organic solvent on its surface you will reductively break it down and make a thin layer on the surface of the lithium metal and this thin layer is what we call the SEI the solid electrolyte interface that the lithium is a solid that we have a liquid electrolyte out here and it's

decomposition generates what is called the solva electrolyte interface that somehow that must be controlling why certain proton donors and certain solvents work well and others do not but that was just a hypothesis and there was really no means of proving this until we started a collaboration with a group that developed a technique known as cryogenic electron microscopy and some of you all may have heard of

this technique one of the Nobel Prize a handful of years ago and the realm of structural biology that one could use electrons to image particular configurations of atoms in the context generally of proteins that if you cool that sample down which is what the word cryogenic is telling us that if we cool it down it'll it will limit the decomposition of that material or that protein

that we're looking at and if we now have a really sensitive electron detector on the other end that can measure single electrons that we can now image proteins and that really has driven a revolution in structural biology that you can use cryogenic electron microscopy to determine the structure of proteins and what we decided to do here was to bring that tool to Material Science to bring

that tool to look at even the interface here of lithium metal with an organic electrolyte that we could actually see the structure of this interface with unprecedented resolution without having the electrons decompose or further break down the surface such that the act of observing the interface wouldn't somehow perturb it and that really was our goal here and so we developed an electrochemical cell in which we

could run this chemistry that we could then take that electrode plunge freeze it in liquid nitrogen and send it into a cryogenic electron microscope and we can now actually look and see this interface that we have lithium metal here we can actually image and see individual atoms and we can look on the surface here and see a very thin decomposition layer here so this dark region

on the surface is the solid electrolyte interface and it contains domains of for instance of lithium hydroxide and other more amorphous regions from thf breakdown when the solid electrode interface is conformal as I'm showing here and rather dense it actually entirely stops reactivity in the system the lithium metal can no longer access nitrogen or the proton donor to be able to make ammonia when instead you

can make a fractured solid electrolyte interface the sort that I'm showing here which is porous and disorganized you can now activate lithium metal to be able to drive this conversion of nitrogen to ammonia and what we found is that if we take electrolytes that work well that have high Faraday efficiencies and then we take electrolytes that don't work well that have low Faraday efficiencies we could

rather easily classify them into these two types of images ones that are conformal and don't work well or seis that are porous and fractured that allow for transport of nitrogen gas through them such that the reaction can happen and so we now finally had a physical handle something that we could see and believe that could tell us as to why a certain solvent or certain proton

donor works well and another doesn't and this was really driven by an interdisciplinary Advance taking a tool from another field and bringing it here to catalysis to be able to understand something new so I've told you a lot so far about ammonia synthesis and I want to now spend just a little bit of time here at the end to tell you about the use of water

as an oxygen atom source and I'll spend just a few minutes here to tell you about one more chemistry in which electrification could be helpful as well so we can look out there and see how we do epoxidation chemistry today we typically start with an olefin react with oxygen make for instance ethylene oxide as a product so this is a very conventional route If This Were

the reaction I would really have no qualms this is done at just 270 to 290 degrees centigrade and 20 bar of pressure but the issue is that a lot of this ethylene oxide over oxidizes it doesn't stop there as a product instead we continue to oxidize going all the way to CO2 as a product and this in part is why epoxide production has the fifth largest

carbon footprint of any chemical that we manufacture today it's because of this over oxidation so it is really important that we find ways of eliminating this carbon footprint this has been recognized for some time so others have tried to develop alternative approaches I show here for instance a chlorohydrine process by which one can react in olefin with hypochlorous acid making a chlorohydrin this chloride can then

be treated with base calcium hydroxide and you make the epoxide but you also make a calcium chloride side product and this calcium chloride side product is sufficiently a problem now because of the brine discharge that you have from those plants that permitting of the coral hydrant process is actually decreasing now so we're seeing fewer and fewer plants getting approved in jurisdictions that recognize the environmental challenge

of having this solid sorry of having the salt discharge stream one could instead use peroxides these are relatively popular processes now starting with an olefin reacting for instance with a peroxide like metacoroparbenzoic acid or hydrogen peroxide you can make the epoxide as a product but my friends who are processed chemists tell me that these reactions remain relatively dangerous at scale there continues to be on average

one fatality a year from epoxidation plants and these are reactions that all too often go wrong because you have Organics in contact with really strong and reactive oxidizers so we can see here that there are a lot of reasons to innovate on epoxidation chemistry the carbon footprint the presence of environmental discharges that are unfavorable and safety all of which conspire to motivate us to make new

methods of driving epoxidation so what we dreamed of in our group was that it would be really interesting if we could instead do epoxidation with water alone if you could take an olefin react with water make an epoxide and co-produce hydrogen that really this is glorified water splitting that instead of breaking apart water making hydrogen and struggling to recombine those oxygen atoms to make O2 and

then just venting it to the universe that we could instead take those oxygen atoms and place them on an olefin to be able to make an epoxide that was really our goal and so in this reaction what we'd want to do is activate water at the anode take that o atom place it on the olefin and then take the electrons send them through the external circuit

take the protons send them through the electrolyte and make hydrogen on the other side and we reasoned in our early work that manganese oxide could be a good Catalyst for this that it's known to activate water but isn't so good at recombining those oxygen atoms and that that may give us just enough time to have this olefin sleep in pick up the O atom and make

the epoxide as the product so we actually found in our early work that we could reach a 30 percent Faraday efficiency we were really excited to see that as a first demonstration of this reaction we found a hundred percent Faraday efficiency for making hydrogen on the other side this was initially with a model substrate cycloctene just to demonstrate that this reaction was even possible we've then

continued to develop new generations of catalysts here I'm showing that you can decorate the manganese oxide with iridium single atoms these iridium single atoms make a local environment on the Catalyst that is even more favorable for epoxidation that we can take what was 30 percent for a faraday efficiency in manganese oxide and make that 50 instead with an iridium decorated Catalyst and now in our lab

and unpublished results we've gotten up to 80 so we're continuing to make this a more and more selective process one which is actually being noticed Now by industry and we're hoping that we'll be able to actually spend this out in something that could help Drive decarbonization of epoxide synthesis so this isn't just about epoxidation you could imagine that you could also perhaps use this to drive

other types of oxygen atom functionalization latinization is a second chemistry that we've achieved where you can take a cyclic Ketone you can actually insert an O atom into this ring and in doing so make a lactone and lactones are of course really interesting as biodegradable monomers and so this is a more sustainable way to access a monomer which will probably have increasing relevance and interest in

the years to come so the last thing I'll mention is that there are two more parts of our group that I I just want to very briefly uh bring attention to here carbon dioxide utilization is really important and I haven't touched on that particular topic here but we're working actually on ways of being able to take CO2 and convert it into long chain hydrocarbons that you

can take a C3 molecule and selectively make it into a C4 by stitching on one more CO2 there's a really interesting chemical tool kit to developed there and we're also working on new ways of enabling efficient electron transfers to bacteria that if we could achieve this we could harness all the selective enzymatic Machinery to make molecules selectively but to do it with Renewable Power to do

it with the power of the sun and the power of wind to drive bacteria to do efficient chemical synthesis as well and with that I'd like to thank the students in postdocs who have been incredible companions on the scientific Journey they've shown such great dedication to the science that they're doing and many of these Concepts have actually come from them so I could thank them for

their dedication to the science and all of you as well for joining in today and I know we'll now transition to q a so thank you all thank you Dr mantherium so we're going to actually begin with a couple technical questions and then lends out to the the more Global um questions so Kevin I think who may be an expert in this field two two questions

has your lab worked with perhaps more active lithium Alloys for ammonia synthesis and for context what is the activity for conventional Haber Bosch catalysts and the units are listed there yeah which I can't say can you say about that yes an animal is per centimeter squared per second right so this will help to give us some idea as to how to actually Benchmark these catalysts yes

um so first on the on the lithium Alloys we've actually tried a series of ways of alloying lithium metal with other alloying agents as a means of trying to modulate its reactivity and what we found so far is that it is just lithium metal that does this reaction effectively as soon as you introduce an allyline agent like tin as one example or many other elements the

periodic table that like to allay with lithium that reactivity of the lithium metal is changed and no longer makes what we want it to so in in the units in the units question that was just asked if you look at a conventional Haber Bosch the reactivity there is around three nanomoles per centimeter squared per second so we're about 10 times higher than that in terms of

per area reactivity at this point so it's really neat to see that these rates are actually higher than what's commercially practiced although there's still a lot of work to do in terms of further increasing the Faraday efficiencies and increasing the Energy Efficiency of this process one of the remarkable things about Haber Bosch is that after a century of innovation that reaction now has a 70 percent

Energy Efficiency what we published that I've shown here today is at a three percent Energy Efficiency an unpublished work we're now at above 10 percent so we're making progress but this really does need to get above about 25 percent in our view to be something that's commercially viable what gives us motivation though is that Haber bash when it was first commercialized was at around 10 to

20 percent Energy Efficiency so that's a process that took several decades and already we're starting to see progress to get to above 10 so we do of course want to continue to continue to see that increase though if this process is exothermic could that heat be then used as a different means of energy production as well absolutely yeah so the the reaction of nitrogen hydrogen is

indeed exothermic that's part of why when you increase temperature you disfavor the equilibrium because it's a reaction that generates heat so if you think back to those color Maps that's something you can justify just based on their appearance that heat you could actually use and so with appropriate heat exchangers you could now couple this to other chemical reactions that could make use of that heat that

you're generating so that kind of integration is really important when one looks at commercial viability of a process so this conversation we could solve it all right now so two more technical questions what do you hypothesize your results would be if the state was brought into a plasma State instead of a gas also does the carbon you use in this process help reuse carbon waste yeah

so plasma-based reactivity is really fascinating this is one of the other contenders out there that are in fact startup companies that are trying to use plasma is to activate nitrogen to make ammonia to me it's really fascinating because there's a long history to trying to use plasmas and and electrical arcs to make nitrogen and demonia in fact before the Haber Bosch process won out and this

was in the 1920s there were there was a flurry of activity in the 1910s to try to use electrical arcs to make nitrogen and pneumonia and there was just a ton of motivation worldwide to make this happen because there were wars being fought over access to Natural fertilizers essentially over bird poop which was one of the best fertilizers available then so if you look back there's

this Rich history to trying to use electrical arcs and plasmas and other means to activate nitrogen the challenge always has been Energy Efficiency those processes have really low energy efficiencies there of course could be a breakthrough that makes it possible but that's exactly where fundamental science needs to be focused to try and make that happen last question about paper boss Bosch which is really trending right

now and okay are there techno-economic or climate benefits to direct electrochemical synthesis of ammonia over a Haber Bosch process HB that uses carbon-free H2 synthesis by EG water Electro electrolysis perfect yeah okay and so if we were to do a techno-economic analysis based on what we think is possible in the next couple years we would likely be making ammonia that's about two to three times more

expensive than Hebrew Bosh today if you think back to one of the earlier plots that I shared looking at how much fertilizers cost in some parts of the world you'll see that this process could actually start to be competitive given that fertilizers especially in stranded locations are more expensive but we do see a decade of research ahead of us to be able to make this something

that could better compete with Haber Bosch and all likelihood these will be complementary Technologies there are other ways of decarbonizing Haber Bosch at immense scales that are likely to be attractive and this is and this what we're developing is likely to be attractive at smaller scales of production local production of ammonia so I think the sort of complementary ecosystem of Technologies in all likelihood will emerge

you say 10 years is completely green energy possible so there's a lot of work to be done and there are a lot of parts of our economy that are difficult to decarbonize and so they're the simple decarbonize things and they're the hard to decarbonize things right and today we've talked about a handful of things in many regard to be difficult to decarbonize parts of the economy

there are others like cement and steel production that also have really large carbon footprints that are thought to be difficult to decarbonize and part of that's technological but more of it is techno-economic in many ways right if we had all the money in the world to decarbonize this chemical manufacturing we could find a way but we know that the world and the developing World in so

many ways relies on these chemicals and materials that it's there's a strong connection between quality of life and cheap access to cement and steel and ammonia and so many other things and so we know that we need cheap solutions to be able to get these things out and that certainly gives a lot of motivation for the science as well and finally what could alumni and this

is a tree how could alumni support this work being becoming more practical in the market yeah so I think there's a lot just an interaction through thought and conversation that we we do quite a few alumni who come through our lab and it for us can be eye-opening to see something from a different perspective I think sometimes in the depths of the lab working on a

problem if you're able to see it from someone else's perspective a lot of good things can happen and so for this you're interested I'd love to have you all reach out and come by and chat with us more about this chemistry thank you so much Dr Mann theorem that's fantastic please give a warm hand thank you all thank you so much well that concludes the presentations

today I want to say thank you so much personally it's been really fun to be here today we've pushed our boundaries together as a community and it has been so fun to engage with you all the slider was interesting uh Caltech people were uniquely intelligent uniquely thoughtful and sometimes actually quite hilarious so that's that's fun and to close finally I'd like to bring out Ralph Amos

the head of the CAA the CEO or the CAA don't leave okay everyone please join me in thanking Sandra for doing such an awesome job today right thank you so much you I mean really you bring to life what is Caltech you embody it and you glue it together in a way that is of a community and it's important so we really appreciate you my pleasure

thank you awesome now I'm going I know you're going now you can go right and thank you for being here uh thank you online um a total of about 800 techers line joined in today uh throughout the world and in this room and we couldn't do this without you we do this for you but it really is about building stronger Community for a place we think

is very important we want to keep the Alumni Association strong our job is to ensure the success and well-being of graduates around the world and we have 26 000 nearly 26 000 alumni who live there just 53 5300 who are just in Southern California so when we get ready to do tables for techers I hope you will sign up raise your hand open up your home

break some bread with techers we'll help bring the guests and uh you're going to do it yes very important sorrow you should check with your spouse or other just don't start bringing people into the house this could be bad we also want to remember that our students many of them will be out in the world so you might have be able to invite students who are

on an internship or they're doing a postdoc at a university if you're in a small town but you're in a University Town you're probably going to have a few techers on the faculty or staff there so we think this is going to work we plan to have hundreds if we can of these dinners going on concurrently over two nights so thank you for being here thank

you for keeping Caltech strong keeping them in your heart and your minds and uh we'll see you soon we have the fall coming up and we have a lot of activities planned so have a great evening be safe and uh go Tech [Applause]