Schaeffler develops new generation of bipolar plates for fuel cell drives with higher power density
Lamborghini unveils Lanzador electric concept

IIT researchers develop electrolyzer that converts CO2 to propane

Researchers at Illinois Institute of Technology (IIT), with colleagues at the University of Pennsylvania and the University of Illinois at Chicago have developed an electrolyzer capable of converting carbon dioxide into propane in a manner that is both scalable and economically viable. A paper on the work is published in

Propane is a tri-carbon (C3) alkane widely used as a fuel. Despite recent advances in CO2 electrocatalysis, the production of C3+ molecules directly from CO2 is challenging due to high reaction barriers and competing reactions to C1, C2 and H2 products.

Here we report a catalytic system composed of 1-ethyl-3-methylimidazolium-functionalized Mo3P nanoparticles coated with an anion-exchange ionomer that produces propane from CO2 with a current density of −395 mA cm−2 and a Faradaic efficiency of 91% at −0.8 V versus reversible hydrogen electrode over 100 h in an electrolyser.

Our characterization and density functional theory calculations suggest that imidazolium functionalization improves the electrocatalytic properties of Mo atoms at the surface and favours the pathway towards propane by increasing the adsorption energies of carbon-based intermediates on the Mo sites. Our results indicate that the ionomer coating layer plays a crucial role in stabilizing the imidazolium-functionalized surface of Mo3P nanoparticles during long-term testing.

—Esmaeilirad et al.


Illustration of electrolyzer, which uses a novel catalyst to convert carbon dioxide into propane. Source: IIT

To ensure a deep understanding of the catalyst’s operations, the team employed a combination of experimental and computational methods. This approach illuminated the crucial elements influencing the catalyst’s reaction activity, selectivity, and stability.

A distinctive feature of this technology, lending to its commercial viability, is the implementation of a flow electrolyzer. This design permits continuous propane production, sidestepping the pitfalls of the more conventional batch processing methods.

The research was supported by the National Science Foundation under Award Number 2135173, the Advanced Research Projects Agency-Energy under Award Number DE-AR0001581, and SHV Energy.


  • Esmaeilirad, M., Jiang, Z., Harzandi, A.M. et al. “Imidazolium-functionalized Mo3P nanoparticles with an ionomer coating for electrocatalytic reduction of CO2 to propane.” Nat Energy doi: 10.1038/s41560-023-01314-8



' an electrolyzer capable of converting carbon dioxide into propane in a manner that is both scalable and economically viable'

If this is indeed the case, and that is an if, together with other light hydrocarbons, why the heck would you want to put a vast battery in a car?

A circular carbon dioxide ecology works, it does not have to be zero carbon dioxide.


The way to prevent co2 emissions seam to be plenty of synthetic carbon neutral fuel, it will work better than batteries and fuelcells.


Use carbon from power plants reuse to reduce emissions

Roger Brown

@Dave Mart: Its not circular unless you have an economical means of removing CO2 from the atmosphere.

Roger Pham

At the present, it costs $600 for removing CO2 per metric ton from the air, = $0.6 per kg of CO2. Propane C3H8 has the same molecular weight as CO2 but 3 times the carbon weight, so $1.8 to make per kg of Propane. Furthermore,, it takes 3 kg of hydrocarbon to equal the energy of 1 kg of H2. So 3 kg of Propane to make using this method would cost $1.8 x 3 = $5.4 just to pay for the cost of CO2 raw material, before any cost of electricity and facility cost.

By contrast, Green H2 is projected to cost $1.5 per kg in the next several years. $1.5 vs $5.4 + $1 electricity cost + $0.5 facility cost. = $6.9 per 3 kg of Propane. We just can't afford to make synthetic electrolytic hydrocarbon due to the massive cost of CO2 from the air! Green H2 will be MUCH CHEAPER!


Getting CO2 from the air is always going to cost a small fortune due to its low concentration of ~400ppm by volume. Seawater has 150 times as much and is also 800 times denser. Here is a group that shows you can get bulk CO2 from seawater in the 35 euro per tonne range. The US Navy is also using seawater to make jet fuel with the carbon source being the seawater. The Navy has already made jet fuel this way and flown a microturbine powered drone on it. Turns out that the CO2 is free in the Navy version of electrolysis machine since the H2 voltage potential is higher the CO2 all comes out before you get a gram of hydrogen. In short air capture is a lost cause seawater is the way to go and since it's in equilibrium with the atmosphere you can never deplete it.


Also the CO2 doesn't have to come directly from the air. You could use CO2 from a ethanol plant where half of the carbon in the grain ends up as fermentation off gas. << this source alone is millions of lbs per year the USA males billions of gallons of ethanol per year. You could also use landfill CO2 off gas or anaerobic sewerage plant off gas. Every city in the USA has both a landfill and a sewerage plant. Go to Kingsford or any other charcoal maker and use the gasses coming off their retorts it's nearly all CO2. Every one of those sources is far FAR less than $600 tonne some are cost negative as in they pay to dispose of the off gas. For far less than. $600 a tonne you can take any old waste biomass or municipal solid or construction wastes and retort it to solid ash and carbon dioxide or monoxide there are well over a billion tonnes per year of crop and biomass wastes with comparable amounts of MSW. Air capture is the last place you should be trying to price CO2 at. The market value for industrial CO2 is currently $60_75 per tonne delivered in tankers less if you have rail access or pipelines to a bulk source. Like a ethanol plant.


This is exactly what I mean a pipeline network for CO2 from biological bulk sources these guys are talking 15million metric tonnes per year that a lot of propane for trucks, locomotives and LDV hybrids to burn cleanly with zero/zero/zero criteria emissions. Cummins already has commercial zero mix,zero pm2.5,zero VOC engines that use methane or LPG. Plus off gas grid homes who don't want to cook with crap electric stoves. Crawfish boils, clam bakes, BBQ grills,BBQ smokers, feed a large group 5 burner Blackstone griddles all need propane why not have clean burning 100% sustainable propane.


As others have noted, getting CO2 directly from the air is a rather different subject.
There are plenty of sources of concentrated streams of CO2 from industrial processes, not just power plants, with the current go to fix seen as carbon sequestration.
Turning it into fuel and making money out of it is clearly a better option than paying for CO2 sequestration, although we need both to actually start to make a dent in our increasing levels.


The cost of the energy for turning CO2 into propane is much, much more than the cost of even atmospheric CO2 capture. (If the cost of green electriciry drops, the cost of carbon capture also drops).

So using propane as a fuel would be foolishly inefficient. Just use fossil fuel, and demand that twice the amount of CO2 emissions from burning the fuel is captured and sequestered. It will still be cheaper and clearly carbon negative.

It is interesting for niche application (like making jet fuel in a war zone using nuclear energy from the carrier) but not for bulk fuel production.

Because of the high purity of the propane, it may be competitive for polymer production



Please share the figures on which you base your claims.
The authors of the paper specifically state:

' an electrolyzer capable of converting carbon dioxide into propane in a manner that is both scalable and economically viable. '

So exactly where did they go wrong?

Roger Brown

I read one interesting (but possibly not very practical) proposal for the circular use of CO2 a number of years ago. In this proposal hydrogen is combined with CO2 to produce methanol (CH3OH) which then transported to turbine generators and used to produce electricity. The CO2 is captured from the turbines and transported back to the electrolysis site where it is again reacted with hydrogen to produce more methanol. If the losses of CO2 in this process are small enough it might be possible to obtain the required CO2 from biological sources in an ecologically sound manner. Of course this proposal does not address the issue of liquid transportation fuels.

Roger Pham

@James Do,
From an article in Smithsonian magazine, "Fuel from Seawater? What’s the Catch?"

"...Using a proprietary electrochemical device, researchers were able to pull carbon dioxide from the water, get hydrogen as a byproduct, and then bounce the two gases off each other to manufacture the liquid fuel. The scientists say they can pull about 97 percent of the dissolved carbon dioxide from the water and convert about 60 percent of the extracted gases into hydrocarbons that can be made into fuel at the cost of approximately $3 to $6 per gallon. The low end is equivalent to today’s jet fuel costs, while the high end would be double the price. The fuel could be commercially viable in 10 years.
So what’s the catch? Well, there are many.

First, carbon dioxide concentration in seawater is about 100 milligrams per liter. That’s 140 times greater than that of air, but still not very much in real terms. One report calculates that you’d have to process close to nine million cubic meters of water to make 100,000 gallons of fuel, and that’s assuming 100 percent efficiency. Assume far less efficiency, and you have to assume much more water. And the more water you process, the more plankton and other little critters you remove from the food chain—with potentially catastrophic results for marine life.

...Then, if 60 percent of the gas is converted, what happens to the other 40 percent, including the 25 percent that becomes environmentally unfriendly methane?

And doesn’t flying jets simply put the carbon back into the atmosphere? Yes, says the Navy, noting that at least in theory, the system would be in constant equilibrium as carbon went from the sea to the air and then back into the sea to be extracted again.

Like every other alternative energy source, seawater fuel will only succeed if everyone agrees that what comes out of the process is worth significantly more than what goes into it. In this case, with national defense as a significant part of the motivation, chances are the research will continue."

Green Hydrogen at $1.50 would be a lot economical and environmental appealing than hydrocarbon at $3 to $6 per GGE.


Green hydrogen has to be stored either at high pressure in certified dedicated pressure vessels or liquefied at cryogenic temperatures and also stored in expensive certified vessels. Then you have to modify your engines and turbines to use this expensively.stored fuel. The density of hydrogen is one third by storage volume so you need larger tanks vs liquid fuels.

Liquids on the other store at room temp and pressure in cheap plastic tanks and have triple the volumetric density. Your tanks will be 1/3 the size for equal amounts of total energy stored. Liquids can be used as is in virtually all existing engines and turbines. No need for 10000psi or 4 degrees above absolute zero cryogenic storage tanks. No need to build out a vast network of fuel stations with those two expensive storage requirements just use the 150,000 existing liquid fuel points.

Even at $6 per gallon it makes better economical sense to burn synthetic fuels in a ICE vs the cheapest model 3 tesla that math is here. $9 per gallon is break even for a VW passat vs model 3 tesla both driven till 150,000 miles.

Liquids store easy, pump fast , it takes less than a min to fuel a hybrid for a 500 mile range. Yes H2 gas takes a few min for refill into a very expensive carbon fiber 10,000 psi tank. Why do all that just put liquids in a plastic tank and go about your life. H2 is a problem looking for a solution.

Green H2 makes sense for use to make liquid synthetic fuels and then into a hybrid car, hybrid semi truck or aircraft.

Seawater is a better source of CO2 vs air but it's not the cheapest or the easiest those are going to be solid waste streams , biomass, or dedicated off gas from other processes already in use. Industrial CO2 is $60 ton forget air capture it's a lost cause. For far cheaper you could just retort any carbon containing material from solid wastes to sewerage sludge to dredging spoils , manures, or.grow seaweed algae or kudzu. Ask Raven to retort it for you to CO2 or CO and H2 gas. Probably as cheap would be to retort it without added steam in the Raven process and you get 1/2 CO and solid carbon +ash bury that carbon + ash in desert climate landfills seal the top with plastic or clay and you just went carbon negative with the carbon locked away for tens of thousands of years vastly cheaper than air capture ever will be. The 1/2 CO from the process has value to.offset the cost of burial.

Roger Pham

It is difficult to predict the future. However, Green H2 is predicted to cost around $1.0 to $1.5 per kg. Adding additional fees and profit at the pump and the price at the pump may rise to $2-$2.5 per kg.
Synthetic liquid fuel is projected to cost $6 to $8 per gallon.
Assuming $6 per gallon for SynFuel, and $2.0 per GGe for Green H2, with hybrid vehicle capable of 50 mpg and 200,000 miles lifespan per car which will consume 4,000 GGe.
The price difference between GH2 and SynFuel is $4 per GGe, x 4,000 GGe = $16,000 higher fuel cost for the SynFuel car.
The cost of the H2 tank is higher than the cost of gasoline tank, at $12 to $15 per kWh of H2 energy x 6kg x 33 kWh = $2376 to $2970.
Other equipment may be needed to monitor H2 leak and valves, but no high-pressure fuel pump system required for H2-combustion car like today's gasoline direct injection engines which require up to 200 bar, and may cost $1,000 to $1,500 extra.

So, the high cost of the SynFuel will far outweight the cost of the H2 fuel tank and fuel system, and H2 combustion engine will be far cleaner than any liquid SynFuel engine can aspire to. There will be ZERO HC, CO, particulate matter...and much lower NOx. An H2 combustion engine is essentially a ZERO-EMISSION engine. NO OIL CHANGE will be needed for H2-combustion engine, because there will be NO carbon fouling of the oil.

The comments to this entry are closed.