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Stanford team develops new low-voltage single-catalyst water splitter for hydrogen production

Researchers at Stanford University have developed a new low-voltage, single-catalyst water splitter that continuously generates hydrogen and oxygen. An open access paper describing the synthesis and functionality of the bi-functional non-noble metal oxide nanoparticle electrocatalysts appears in the journal Nature Communications.

In the reported study, the new catalyst achieved 10 mA cm−2 water-splitting current at only 1.51 V for more than 200 h without degradation in a two-electrode configuration and 1 M KOH—better than the combination of iridium and platinum as benchmark catalysts.

Electrochemical/photoelectrochemical water splitting is widely considered to be a critical step for efficient renewable energy production, storage and usage such as sustainable hydrogen production, rechargeable metal-air batteries and fuel cells. Currently, the state-of-the-art catalysts to split water are IrO2 and Pt for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, with ~1.5 V to reach 10 mA cm−2 current (for integrated solar water splitting). However, the price and scarcity of these noble metals present barriers for their scale-up deployment.

A great deal of effort and progress have been made towards efficient OER and HER catalysts with earth-abundant materials, such as cobalt phosphate, perovskite oxides and transition metal oxides (TMOs)/layer-double-hydroxides for OER and transition metal dichalcogenides and nickel molybdenum alloy for HER. However, pairing the two electrode reactions together in an integrated electrolyzer for practical use is difficult due to the mismatch of pH ranges in which these catalysts are stable and remain the most active. In addition, producing different catalysts for OER and HER requires different equipment and processes, which could increase the cost. Therefore, developing a bifunctional electrocatalyst with high activity towards both OER and HER in the same electrolyte becomes important yet challenging.

… Here we demonstrate a novel bifunctional catalyst of lithium-induced ultra-small NiFeOx nanoparticles (NPs), with a remarkable performance of only 1.51 V (280 mV overpotential) to achieve 10 mA cm−2 current in 1 M KOH solution for long-term operation.

—Wang et al.

A conventional water-splitting device consists of two electrodes submerged in a water-based electrolyte. A low-voltage current applied to the electrodes drives a catalytic reaction that separates molecules of H2O, releasing bubbles of hydrogen on one electrode and oxygen on the other. Each electrode is embedded with a different catalyst, typically platinum and iridium.

In 2014, Stanford chemist Hongjie Dai developed a water splitter made of inexpensive nickel and iron that runs on an ordinary 1.5-volt battery. (Earlier post.)In the new study, Profesor Yi Cui and his colleagues advanced that technology further.

In conventional water splitters, the hydrogen and oxygen catalysts often require different electrolytes with different pH—one acidic, one alkaline—to remain stable and active. An expensive barrier is needed to separate the two electrolytes, adding to the cost of the device, said graduate student Haotian Wang, lead author of the study.

Our water splitter is unique, because we only use one catalyst, nickel-iron oxide, for both electrodes. Our single-catalyst water splitter operates efficiently in one electrolyte with a uniform pH.

—Haotian Wang

To find catalytic material suitable for both electrodes, the Stanford team borrowed a technique used in battery research called lithium-induced electrochemical tuning. The idea is to use lithium ions to chemically break the metal oxide catalyst into smaller and smaller pieces.

Breaking down metal oxide into tiny particles increases its surface area and exposes lots of ultra-small, interconnected grain boundaries that become active sites for the water-splitting catalytic reaction. This process creates tiny particles that are strongly connected, so the catalyst has very good electrical conductivity and stability.

—Yi Cui

Haotian discovered that nickel-iron oxide is a world-record performing material that can catalyze both the hydrogen and the oxygen reaction, Cui said. “No other catalyst can do this with such great performance.

By improving both OER and HER activities, the galvanostatic cycling method successfully elevates the efficiency of water-splitting electrolyzer at 10 mA cm−2 current to 81.5% using only one material, making good preparations for the scale-up of water photolysis/electrolysis with high efficiency and low cost. Synthesizing catalysts on conducting substrates can maximally reduce the use of carbon additives and also get rid of polymer binders, which enables high-current operations (circumvent bubble-releasing problems introduced by the hydrophobic nature of carbon) and also performs superior stabilities. In addition, the successful demonstration of the Li conversion reaction method in improving water-splitting catalysis may help to inspire the improvements of other important TMOs applications including oxygen reduction reactions, supercapacitors, carbon dioxide reductions and so on.

—Wang et al.


  • Haotian Wang, Hyun-Wook Lee, Yong Deng, Zhiyi Lu, Po-Chun Hsu, Yayuan Liu, Dingchang Lin & Yi Cui (2015) “Bifunctional non-noble metal oxide nanoparticle electrocatalysts through lithium-induced conversion for overall water splitting” Nature Communications 6, Article number: 7261 doi: 10.1038/ncomms8261



A way to turn sunlight or wind into energy that can be used even when the sun goes down or the wind stops blowing. Another clean energy source to live off the grid! When can it be commercialized Oh yeah 5 years right? How expensive is it? Probably out of this world expensive.
Let me know when can do something like run my car with this.


This may be one more way to produce low cost clean H2 for our future FCEVs?


@D...please do not give up. It will all come. It is just a matter of time. Five years is a very very short time.


O2 for biomass gasification abd bio CO2


200 million cars that can use bio synthetic fuel,
200,000 EVs with a slow adoption rate.


I will not fault their research as I truly believe that knowledge is important. However, the idea that we can use surplus "green" electric power to make hydrogen or other liquid fuels seems unrealistic. We only generate a few percent of our electric power with wind or solar. If we have more wind or solar power, it makes much more sense to just quit using coal and then cut back on natural gas. If we ever got to the point that where we had a temporary surplus of "green" power, it would make more sense to pump water uphill.



If by "we" you mean America as a whole you are correct, but some places are already producing surpluses of RE energy. Denmark, parts of Spain and some towns in Germany come to mind.


One of these near future days "we" may mean the 8+B people living on Earth.

Asia and EU will certainly make up a much larger relative piece of the economic pie.

Bob Wallace

I read this as a possible cost savings in the electrolyser hardware. Did I miss something about an increase in efficiency or will it still take the same amount of electricity to produce a given amount of hydrogen?

Getting the cost of the production plant may make it possible to run the plant only part time, letting it use the cheapest available electricity. But as EVs and storage come online the price of electricity should no longer "approach zero".


Solar is well set up to be on a ferocious growth tear for quite a while

First Solar CEO: ‘By 2017, We’ll Be Under $1.00 per Watt Fully Installed’

That's 3.5 cents per kilowatt-hour unsubsidized in Texas.

This kind of research may not go anywhere but it is probably best to keep researching ways to use cheap excess energy.


@ai vin

I probably was mostly thinking of America when using "we" but the only place that probably has an excess of "clean power" is Iceland in the form of Hydro and Geothermal energy along with a small population. Germany is burning Peat to generate electricity which has to be worse than coal. Also, the US is shipping wood pellets to some European countries including Denmark to burn for electric power which is somehow counted as "green power"??? What I am trying to say is to replace this power instead of trying to make hydrogen or liquid fuels.

@Bob Wallace

I think that the measure of efficiency is the amount of overpotential. The article mentions 1.51 V (280 mV overpotential) to reach a certain current density and they give an efficiency of 81.5% which I take to mean that the overall energy value of recombining the hydrogen and oxygen is 81.5% of the energy that when into splitting it. No free lunch.


@Bob Wallace

Just doing the math: (1.51 - 0.28) / 1.51 = 1.23 / 1.51 = 0.81457 = 81.5%


Our area can produce close to 48,000 mega-watt with private and public (hydro + wind) facilities.

Another 50,000+ mega-watt could be added when demand exist.

Our peak demand, on coldest winter days, is around 44,000 mega-watt. Peak demand for the other 3 seasons is under 26,000 mega-watts.

The largest current users are the 6 very large aluminum facilities. New technology being developed in France could reduce the energy required to produce aluminum by about 50%. That would leave more RE for H2 production.

With the exception of a few hours on very cold winter days, surplus-excess clean RE (at under 0.03/kWh) could be used to produce very clean H2.


"for more than 200 h without degradation"

is that a typo? 200 hours amounts to being a lab experiment


Yep, it's not scaled up, but that's not the point. If it can be scaled up, and can be powered from green, what's not to like? We're not there, maybe, but we're getting there. The downside of BEVs seems to be that the batteries degrade more quickly than advertised, and the codt of replacement & labor is huge. It makes H2 cars look more attractive. You can get a 3 year old Leaf for $7,000. Go for it.


Our Hydro-Wind network could sell unused RE surpluses at under $0.01/kWh (or less) during off-peak demand hour (about 90% of the time) to produce clean H2, instead of not using/selling it.

H2 produced with future high efficiency electrolysers and very low cost clean electricity will compete favourably with fossil/bio liquid fuels at $1.35/L and a $100/tonne carbon tax.

Of course, a special road usage tax will have to be applied to EVs and FCEVs to compensate for the current fuel taxes.

Bob Wallace

There are currently a few times a year when electricity prices drop low. That's mainly because nuclear and coal would rather sell at a loss rather than shut down and restart. Those plants will go away, as will the subsidies for wind which allow wind to bid in as low a 1 cent per kWh and still make a profit.

EVs and storage are starting to come on line. They will eat up those cheap kWh and raise the price floor.

The days of <3.5c/kWh are limited. As are the current hours those prices are seen. One cannot supply hydrogen or syn fuel based on a few late night price drops. Especially seeing that those bargains are temporary.

Furthermore, in order to supply the nation's fuel needs with H2/sys it would take massive additional wind/solar buildout. There's not enough 'surplus' capacity to power the sort of fuel plants that would be required.

If your H2/syn solution won't work at industrial electricity prices then it's going nowhere. No one will build the capacity needed and sell it to you unless they are recovering costs and making a profit.


BW...clean low cost H2 production and storage, with more efficient electrolisers, make economic sense in areas where you have to 'dump' water and wind energy 16+ hours/day and almost 24/7 during very low load periods.

Hydro with very large water reservoirs (fortunate few) can stock water for a while but you cannot do it with straight river falls and wind. You use it, store it or lose it.

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