> "Initially, we did not believe it because the prevailing view is that Mn impairs the corrosion resistance of stainless steel. Mn-based passivation is a counter-intuitive discovery, which cannot be explained by current knowledge in corrosion science. However, when numerous atomic-level results were presented, we were convinced. Beyond being surprised, we cannot wait to exploit the mechanism," said Dr. Kaiping Yu, the first author of the article, whose PhD is supervised by Professor Huang.
This is the Cannot be explained bit
Uh, dumb question, how is 1.7 volts "ultra high potential" ? Is that even enough to do electrolysis like they're talking about?
"Hong Kong researchers develop corrosion-resistant steel for seawater hydrogen electrolysis"
The three stooges effect I see. Too many corrosive elements, they stop each other from getting through the door.
The limiting factor is that natural gas is very cheap and cracking it to make blue hydrogen is really easy at scale, and gives off CO2 which is useful for injection into wells to increase production. That sets a price ceiling of hydrogen.
At the other end of the scale, there are batteries to store 'free' electricity and resell later. That sets a floor price of electricity.
Between the floor price of the input and ceiling price of the output, there is no room for electrolysis, even at 100% efficiency, unless government policies mandate it or restrict batteries or blue hydrogen.
Splitting water into free hydrogen and oxygen is important because it is an essential step for using electrical energy in the chemical and metallurgic industries.
For long term energy storage, free hydrogen is not a good solution, but it can be used to synthesize hydrocarbons, which are suitable for long term energy storage or for aerospace transportation.
Even with abundant and cheap dihydrogen, using it for energy storage in vehicles is a bad idea.
"Natural gas at Texas’s Waha hub is trading at negative $7.05 per million British Thermal Units, hitting a record low of negative $9.52 on April 15."
https://www.barrons.com/articles/natural-gas-texas-negative-...
There are different kinds of water electrolysis equipment, with different capital expenditure and operating expenses.
"Alkaline electrolyzers are cheaper in terms of investment (they generally use nickel catalysts), but least efficient. PEM electrolyzers are more expensive (they generally use expensive platinum-group metal catalysts) but are more efficient and can operate at higher current densities, and can, therefore, be possibly cheaper if the hydrogen production is large enough."
https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficien...
Anything using platinum-group metals will be very expensive. Therefor catalytic converters in cars use very little platinum-group metals.
"The amount of palladium in a converter can vary, but it is typically around 2-7 grams." https://vehiclefreak.com/how-much-palladium-is-in-a-catalyti...
Yes, but I think this the most likely outcome. Natural gas is only cheap in certain areas, and the past few years have made everyone very, very aware of the geopolitics involved in getting hold of it. While global warming is not going away, and I question the extent to which CCS actually happens with blue hydrogen.
Batteries are capital equipment in the same way as electrolysers are. They're great at short term storage, but medium-term is still a bit more of an issue. "Restrict batteries" is obviously not on the table except for stupid retail corner cases where utilities have captured the regulator.
There's a potential market for lots of green H2 in Haber nitrogen, metals refining, and synthetic jet fuel etc, but only if the cheap CO2 emitting option is priced out or banned, or H2 electrolysers get comparable capital prices to battery storage.
If this works out at scale (lots of problems can be found between a lab discovery and mass production), this is legitimately a very good thing for renewables.
Now, yes, as long as natural gas is cheap(inbetween US or Soviet wars) it'll probably be the core for hydrogen, however batteries won't help much in the north since the transmission rather than usage is the cap even with batteries so excess production could be redirected towards hydrogen production.
Huh?
I’d be interested in hearing about some scenario where this actually costs less, given the cost of building anything nuclear in 2026.
A stainless steel breakthrough from the University of Hong Kong (HKU) could help solve one of the biggest problems facing green hydrogen: how to build electrolyzers that are tough enough for seawater, yet cheap enough for large scale clean energy.
Led by Professor Mingxin Huang in HKU's Department of Mechanical Engineering, the team developed a special stainless steel for hydrogen production (SS-H2). The material resists corrosion under conditions that normally push stainless steel past its limits, making it a promising candidate for producing hydrogen from seawater and other harsh electrolyzer environments.
The discovery, reported in Materials Today in the study "A sequential dual-passivation strategy for designing stainless steel used above water oxidation," builds on Huang's long running "Super Steel" Project. The same research program previously produced anti-COVID-19 stainless steel in 2021, along with ultra strong and ultra tough Super Steel in 2017 and 2020.
A Cheaper Path Toward Green Hydrogen
Green hydrogen is made by using electricity, ideally from renewable sources, to split water into hydrogen and oxygen. Seawater is an especially tempting feedstock because it is abundant, but it brings a serious materials problem: salt, chloride ions, side reactions, and corrosion can quickly damage electrolyzer components.
Recent reviews of direct seawater electrolysis continue to highlight the same core challenge. The technology could provide a more sustainable route to hydrogen, but corrosion, chlorine related side reactions, catalyst degradation, precipitates, and limited long term durability remain major obstacles to commercial use.
That is where SS-H2 could matter. In a salt water electrolyzer, the HKU team found that the new steel can perform comparably to the titanium based structural materials used in current industrial practice for hydrogen production from desalted seawater or acid. The difference is cost. Titanium parts coated with precious metals such as gold or platinum are expensive, while stainless steel is far more economical.
For a 10 megawatt PEM electrolysis tank system, the total cost at the time of the HKU report was estimated at about HK$17.8 million, with structural components making up as much as 53% of that expense. According to the team's estimate, replacing those costly structural materials with SS-H2 could reduce the cost of structural material by about 40 times.
Why Ordinary Stainless Steel Fails
Stainless steel has been used for more than a century in corrosive environments because it protects itself. The key ingredient is chromium. When chromium (Cr) oxidizes, it creates a thin passive film that shields the steel from damage.
But that familiar protection system has a built in ceiling. In conventional stainless steel, the chromium based protective layer can break down at high electrical potentials. Stable Cr2O3 can be further oxidized into soluble Cr(VI) species, causing transpassive corrosion at around ~1000 mV (saturated calomel electrode, SCE). That is well below the ~1600 mV needed for water oxidation.
Even 254SMO super stainless steel, a benchmark chromium based alloy known for strong pitting resistance in seawater, runs into this high voltage limit. It may perform well in ordinary marine settings, but the extreme electrochemical environment of hydrogen production is a different challenge.
The Steel That Builds a Second Shield
The HKU team's answer was a strategy called "sequential dual-passivation." Instead of relying only on the usual chromium oxide barrier, SS-H2 forms a second protective layer.
The first layer is the familiar Cr2O3 based passive film. Then, at around ~720 mV, a manganese based layer forms on top of the chromium based layer. This second shield helps protect the steel in chloride containing environments up to an ultra high potential of 1700 mV.
That is what makes the finding so striking. Manganese is usually not viewed as a friend of stainless steel corrosion resistance. In fact, the prevailing view has been that manganese weakens it.
"Initially, we did not believe it because the prevailing view is that Mn impairs the corrosion resistance of stainless steel. Mn-based passivation is a counter-intuitive discovery, which cannot be explained by current knowledge in corrosion science. However, when numerous atomic-level results were presented, we were convinced. Beyond being surprised, we cannot wait to exploit the mechanism," said Dr. Kaiping Yu, the first author of the article, whose PhD is supervised by Professor Huang.
A Six Year Push From Surprise to Application
The path from the first observation to publication was not quick. The team spent nearly six years moving from the initial discovery of the unusual stainless steel to the deeper scientific explanation, then toward publication and potential industrial use.
"Different from the current corrosion community, which mainly focuses on the resistance at natural potentials, we specializes in developing high-potential-resistant alloys. Our strategy overcame the fundamental limitation of conventional stainless steel and established a paradigm for alloy development applicable at high potentials. This breakthrough is exciting and brings new applications," Professor Huang said.
The work has also moved beyond the laboratory. The research achievements have been submitted for patents in multiple countries, and two patents had already been granted authorization at the time of the HKU announcement. The team also reported that tons of SS-H2 based wire had been produced with a factory in Mainland China.
"From experimental materials to real products, such as meshes and foams, for water electrolyzers, there are still challenging tasks at hand. Currently, we have made a big step toward industrialization. Tons of SS-H2-based wire has been produced in collaboration with a factory from the Mainland. We are moving forward in applying the more economical SS-H2 in hydrogen production from renewable sources," added Professor Huang.
Why the Timing Still Matters
Although the SS-H2 study was published in 2023, its core problem has only become more relevant. Newer seawater electrolysis research continues to focus on the same bottlenecks: corrosion resistant materials, long lasting electrodes, chlorine suppression, and system designs that can survive real seawater rather than ideal laboratory solutions. A 2025 Nature Reviews Materials review described direct seawater electrolysis as promising but still held back by corrosion, side reactions, metal precipitates, and limited lifetime.
Other recent work has explored stainless steel based electrodes with protective catalytic layers, including NiFe based coatings and Pt atomic clusters, to improve durability in natural seawater. Researchers have also reported corrosion resistant anode strategies built on stainless steel substrates, showing that stainless steel remains a major focus in the effort to make seawater electrolysis more practical.
This newer research does not replace the SS-H2 discovery. Instead, it reinforces why the HKU team's approach is important. The field is still searching for materials that can survive the punishing mix of saltwater chemistry, high voltage, and industrial operating demands. SS-H2 stands out because it attacks the problem not only with a coating or catalyst, but with a new alloy design strategy that changes how stainless steel protects itself.
A Steel Breakthrough With Clean Energy Potential
SS-H2 is not yet a plug and play solution for the hydrogen economy. The team has acknowledged that turning experimental materials into real electrolyzer products, including meshes and foams, still involves difficult engineering work.
Even so, the promise is clear. A stainless steel that can withstand high voltage seawater conditions while replacing expensive titanium based components could make hydrogen production cheaper, more scalable, and easier to pair with renewable energy.
For a field where cost and durability often decide whether a technology can leave the lab, a steel that builds its own second shield may be more than a materials science surprise. It could become a practical step toward cleaner hydrogen at industrial scale.