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Researchers design nanoparticles for cost-effective hydrogen production process

Researchers at the University of Arkansas, with colleagues from Brookhaven National Lab and Argonne National Lab, have found that nanoparticles composed of nickel and iron are more effective and efficient than other more costly materials when used as catalysts in the production of hydrogen fuel through water electrolysis.

A paper on their work is published in the journal Nanoscale.

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Researchers at the U of A have designed nanoparticles that act as catalysts, making the process of water electrolysis more efficient. Credit: Jingyi Chen, Lauren Greenlee and Ryan Manso.

Controlling the 3-D morphology of nanocatalysts is one of the underexplored but important approaches for improving the sluggish kinetics of the oxygen evolution reaction (OER) in water electrolysis. This work reports a scalable, oil-based method based on thermal decomposition of organometallic complexes to yield highly uniform Ni–Fe-based nanocatalysts with a well-defined morphology (i.e. Ni–Fe core–shell, Ni/Fe alloy, and Fe–Ni core–shell). Transmission electron microscopy reveals their morphology and composition to be NiOx–FeO/NiOx core-mixed shell, NiOx/FeOx alloy, and FeOx–NiOx core–shell.

… The Ni diffusion from the amorphous Ni-based core to the iron oxide shell makes the NiOx–NiOx/FeOx core-mixed shell structure the most active and the most stable nanocatalyst, which outperforms the comparison NiOx/FeOx alloy nanoparticles expected to be active for the OER.

This study suggests that the chemical environment of the mixed NiOx/FeOx alloy composition is important to achieve high electrocatalytic activity for the OER and that the 3-D morphology plays a key role in the optimization of the electrocatalytic activity and stability of the nanocatalyst for the OER.

—Manso et al.

University of Arkansas researchers Jingyi Chen, associate professor of physical chemistry, Lauren Greenlee, assistant professor of chemical engineering and colleagues discovered that when nanoparticles composed of an iron and nickel shell around a nickel core are applied to the process, they interact with the hydrogen and oxygen atoms to weaken the bonds, increasing the efficiency of the reaction by allowing the generation of oxygen more easily. Nickel and iron are also less expensive than other catalysts, which are made from scarce materials.

… we developed a scalable, oil-based synthesis based on the thermal decomposition of organometallic complexes that could manipulate both the morphology and crystalline phase of the Ni–Fe-based nanocatalysts. Highly uniform Ni–Fe-based nanostructures with different morphologies (i.e. Ni–Fe core–shell, Ni/Fe alloy, and Fe–Ni core–shell) were synthesized via either sequential or simultaneous injection.

… the amorphous, disordered nature of the NiOx core, which appears to be most similar to α-Ni(OH)2, allowed the diffusion of Ni into the FeOx for the NiOx–NiOx/FeOx core-mixed shell nanoparticles. The resultant mixed metal hydroxide/oxide shell provided the most active and stable nanocatalyst, which outperformed the comparison NiOx/FeOx alloy nanoparticles with a 1 : 1 composition expected to be active for the OER. These findings highlight that not only the crystallinity, but also the 3-D morphology, phase, and chemical environment of both metal species, disorder, and composition can significantly affect the electrocatalytic activity and stability of nanocatalysts for the alkaline OER.

—Manso et al.

Resources

  • Ryan H. Manso, Prashant Acharya, Shiqing Deng, Cameron C. Crane, Benjamin Reinhart, Sungsik Lee, Xiao Tong, Dmytro Nykypanchuk, Jing Zhu, Yimei Zhu, Lauren F. Greenlee* and Jingyi Chen (2019) “Controlling the 3-D morphology of Ni–Fe-based nanocatalysts for the oxygen evolution reaction” Nanoscale doi: 10.1039/C8NR10138H

Comments

HarveyD

Good news for eventual lower cost clean H2 for future fast growing H2 economy?

sd

Not really. You still need to provide the energy to convert the water to H2 and O2 and not matter how good the catalyst is you will still end up using about twice the energy generating H2 and then using it in a fuel cell as just putting it in a battery and using it directly.

Davemart

@sd:

There are provisos to that.

OK if the electricity is available when you need it.
With renewables, they are mostly not.

Power on demand is a different game entirely to power which isn't, otherwise cargo would still be moved by sailing ships.

And if it is cold, then the range on a battery is substantially decreased, on an FCEV process heat covers it.

The fuel cell stack in the Hyundai Nexo is around 60% efficient, which is pretty darn good, although there is still room for improvement and we aren't at the ceiling yet.

Lad

Davemart:
Boy, you're a hard sell. 60% is not efficient and is overstated when you include the electric driveline in the calculation, especially when compared to solar generated power used by batteries to power electric motors.

If you use surplus electricity to create the hydrogen that might be used in unique applications, i.e., hybrid aircraft and/or seagoing ships that would otherwise used jet fuel or bunker oil as fuel, I would agree; but, only because it's cleaner. However, to power common vehicles, i.e., car, trucks, buses and trains. with hydrogen makes no sense from an efficiency standpoint.
Hydrogen was introduced and is supported as a substitute for gasoline/diesel by the oil interest...it's really that simple:
https://www.youtube.com/watch?v=f7MzFfuNOtY

yoatmon

Silicon carbide inverters from Fraunhofer = / > 99 %:
https://www.iisb.fraunhofer.de/en/research_areas/vehicle_electronics/dcdc_converters/products_services.html
EV-Motors = / > 95%:
http://www.metricmind.com/category/ev-ac-drive-systems/ev-motors/
LIBs with coulombic efficiencies ov 95 to 98 % e. g.:
https://www.mdpi.com/1996-1073/10/5/597/htm
Who would genuinely expect Fool Cells to even get close to the efficiency of a BEV let alone to draw a match?

Engineer-Poet

yoatmon, coulombic efficiency is not energy efficiency; your charging voltage is always higher than discharge voltage.

I had to dig into the issue of coulombs vs. energy in this piece.  It was informative but not what I would call encouraging; you can have plenty high coulombic efficiency while still turning 50% of your input into waste heat.

HarveyD

REs are growing at a very fast rate in many countries and will create more periods of clean e-energy surpluses. Using these surpluses to create clean storable H2 (and/or liquid cleaner fuels) at a lower price is a strong possibility.

Contrary to NPPs, future solar panels, electrolysers and FCs will be more efficient and cost less than todays.

sd

Hydrogen has lots of problems. You have to make it, compress it, transport it, and store it and you really cannot store it without some leakage. About the best number I could find for electrolysis efficiency was 79% and a more typical efficiency is 70% or less. By the time you add in compression loss, you are down to 73% at best or more typically ~65% or less. Then with the Fuel cell efficiency of 60% you are down to 39% to 43% and this is without transport. Also with a fuel cell vehicle, you still have to account for the same losses that you would have with a BEV, inverter, motor, and battery inefficiencies.

Sheldon Harrison

For the folks who like to talk about H2 from solar and wind directly to batteries. I have a few questions to ask.
1. Will your vehicle always be plugged in somewhere when the sun is shining. Note, humans generally are up and about in the day and sleep at night.
2. Will the wind always blow hard in your neck of the woods at night, every night, reliably throughout the year, irrespective of season?
3. If the answer to the above two questions is No, then will you invest in a separate stationary battery, capable of storing at least 1 week's worth of output to charge your BEV, when available? If you will, how much will it cost for that duplicative investment and what will the cost of your PV power eventually be when you amortize the cost of that battery?
4. If you leave the BEV for 1 month, 2 months etc., especially outside in winter conditions, how much battery capacity remains when you return.

Thank you for your response

HarveyD

A PHEV with a small FC or a regular FCEV with a small battery pack could better meet all those requirements?

SJC

sd,
Put fossil fuels in a power plant, transmit the electricity, convert it with a battery charger, store it in batteries, then get it back out of the batteries...let me know how efficient that is compared with NG to H2 to FC.
You can make H2 at the point of use by reforming NG, use renewable methane for less fossil carbon.

yoatmon

@ Sheldon Harrison:
Innolith has supplied a battery bank for grid support in Maryland. This battery eliminates the problems that you are referring to but the problems with H2 remain adamantly.
https://www.greentechmedia.com/articles/read/lithium-battery-hopeful-innolith-rises-from-alevos-ashes

yoatmon

@ EP:
LIBs are charged in a 3 or 4 step procedure. The more steps the higher the time consumption for a complete charge. The first steps occur in constant current mode; the final step at constant voltage (4.25V). This charging mode is employed in almost all charging modi. If you were charging a single cell only you can charge completely at constant voltage mode without encountering enormous heat losses. A complete battery with cells switched in parallel and series circuitry and charged in constant voltage mode would encounter tremendous heat losses but not in a step by step charging procedure. The nominal cell voltage is given at 3.6V; peak voltage at 4.25V.

Engineer-Poet

yoatmon, please try to keep track of the subject.  You wrote:

LIBs with coulombic efficiencies ov 95 to 98 %

Coulombic efficiency is not energy efficiency; it's about what fraction of electrons are used, not how much of their energy is applied as desired.  Going on and on about battery charging rates is descending toward AlzHarvey levels of irrelevance.  You're better than that.

Engineer-Poet

@Sheldon Harrison:  Note the total lack of straight answers to your perfectly reasonable questions.

sd

SJC

Read https://en.wikipedia.org/wiki/Steam_reforming

The efficiency is about 65-70% but there is a note that the process does not scale well. Then you lose about 10% in compression so you are at 58-63% and then 60% for the fuel cell and you have 35-38% at best. Also, you still need to account for transportation losses somewhere.

The newer combined cycle gas turbines are about 60% efficient (GE was claiming 62% last year). Even if you lose 10% in transmission, you still have 54% and all the battery stuff cancels out as you need the batteries anyway in a fuel cell vehicle. Hydrogen does not win

SJC

SD,
You did not get the point.

Combined cycle does not make up much of the grid, not all are 60%.
I asked you to add up all the loses, you did not.

When you make the H2 at point of use there is NO transportation.
The renewable methane comes via NG pipes efficiently.

yoatmon

I'm well aware of the fact that coulombic (CE)- and energy efficiency (EE) is not the same. The charge efficiency of electron transfer within cells / batteries is meant with CE and is the ratio of the total output extracted from a cell / battery to the total input charge covering a complete cycle. Under normal operating conditions LIBs achieve a CE over 99%.
Energy efficiency is entirely dependent on a moderate charge and discharge rate. High charge and discharge rates (multiples of the recommended C-rate) will result in a rather lousy energy efficiency.
It was not my intention - and still is so - not to write a book in this comment section.
Evidently you cannot or refuse to read between the written lines and interpret everything as is to your liking.

Tim Duncan

@All of you. Really enjoy the discussions here for their passion and technical insights (not 100% but mostly interesting), thx. A couple of honest questions:

- Why is electrolysis not done at elevated pressure to avoid subsequent compression expense in the gas phase?
- How does this really move the needle on cost, what do they mean? Neither cost nor efficiency seem well quantified in the article.
- Why are some many commenting on electrolysis & FC efficiency when discussing "free electricity" from RE oversupply? If RE is so cheap this discussion should focus on battery vs VC costs, right?
- IF RE (renewable electricity) surplus were put accross the grid at scale, what would the infrastructure upgrades cost, from transmission to getting it hooked to all the EVs parked at home (~2.5 cars each), work, grocery store etc? I'm guessing Trillions, many grid segments including electrical service (last mile) would be easily overloaded.
- Why won't anyone directly answer Sheldon Harrison's Q's?
- When you say "reform on demand" does that refer to a neighborhood filling station or in the vehicle? I was not aware mobile reformer technology had developed to any

Engineer-Poet

yoatmon, let me remind you of what you wrote:

Silicon carbide inverters from Fraunhofer = / > 99 %:
https://www.iisb.fraunhofer.de/en/research_areas/vehicle_electronics/dcdc_converters/products_services.html
EV-Motors = / > 95%

You then shifted from ENERGY efficiency to coulombic efficiency, which is a category error; the two are incommensurable.  Worse, even if you were only guilty of unclear thinking, someone who learns the difference later is likely to think that you used that ambiguity to lie to them.

Seriously not picking on you here.  The level of discourse needs to go upward, and that starts by not tolerating errors of fact just because they make "your side" look better.  If "your side" is not defined by factual truth as the foundation for everything else, you're already a failure at best.

Evidently you cannot or refuse to read between the written lines and interpret everything as is to your liking.

If you've got category errors in your statements (even if the average person would not catch them) whatever you put "between the lines" is both irrelevant and counterproductive; if you try to play a shifty game instead of being direct and forthright, nobody should believe anything you say.  Notice that I don't mince words with anyone?  That's why.

Engineer-Poet
- Why is electrolysis not done at elevated pressure to avoid subsequent compression expense in the gas phase?

Dissolved gas can migrate to the opposite electrode and recombine, and the higher the pressure the more gas stays in solution.

- Why are some many commenting on electrolysis & FC efficiency when discussing "free electricity" from RE oversupply?

Somebody is still paying for the "free" electricity even if the wholesale cost is driven to zero.  The blades, nacelle, tower, base and transmission wires cost money.  Shifting the cost via tax credits or fixed feed-in tariffs or whatever makes neither the cost nor the environmental impact of all the stuff and its manufacturing go away.  All it does is change who pays.  You have the same problem on the consumption end:  electrolyzers, water purification, gas compressors and tanks all cost money.  Most of the pieces require maintenance; high-pressure gas systems require regular and thorough safety inspections.

You have to get the money to pay for this stuff somehow, and the less efficient you are (or the less often your equipment gets used) you have to recover those costs from less product.  That means either higher prices or "someone else" pays once again.  Well, most people aren't made of money and if Ontario is any hint the limits of what "someone else" can pay are already here.

- Why won't anyone directly answer Sheldon Harrison's Q's?

I can't answer them because they are for the renewablistas, which I'm not.  The renewablistas can't answer them because it would expose the bankruptcy of their position.

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