A new sustainable and practical method for producing hydrogen from water has been discovered by a team of researchers at the RIKEN Center for Sustainable Resource Science (CSRS) in Japan led by Ryuhei Nakamura. Unlike current methods, the new method does not require rare metals that are expensive or in short supply. Instead, hydrogen for fuel cells and agricultural fertilizers can now be produced using cobalt and manganese, two fairly common metals. The study was published in Nature Catalysis.
Unlike conventional fossil fuels that generate carbon dioxide upon combustion, hydrogen is a clean fuel that only produces water as a byproduct. If hydrogen can be extracted from water using renewable electricity, the energy grid can be made clean, renewable, and sustainable. Additionally, hydrogen is the key ingredient needed to produce ammonia, which is used in virtually all synthetic fertilizers. But instead of cleanly extracting hydrogen from water, currently, ammonia plants use fossil fuels to produce the hydrogen they need.
So why are we still using fossil fuels? One reason is that the hydrogen extraction process itself—electrolysis—is expensive and not yet sustainable.
“This is primarily due to a lack of good catalysts,” says Nakamura. “In addition to being able to withstand the harsh acidic environment, the catalyst must be very active. If not, the amount of electricity needed for the reaction to produce a given amount of hydrogen soars, and with it, so does the cost.”
Currently, the most active catalysts for water electrolysis are rare metals like platinum and iridium, which creates a dilemma because they are expensive and considered “endangered species” among metals. Switching the whole planet to hydrogen fuel right now would require about 800 years’ worth of iridium production, an amount which might not even exist. On the other hand, abundant metals such as iron and nickel are not active enough and tend to dissolve immediately in the harsh acidic electrolysis environment.
Mixed Cobalt and Manganese Oxides
In their search for a better catalyst, the researchers looked at mixed cobalt and manganese oxides. Cobalt oxides can be active for the required reaction, but corrode very quickly in the acidic environment. Manganese oxides are more stable, but are not nearly active enough. By combining them, the researchers hoped to take advantage of their complimentary properties. They also had to consider the high current density needed for practical application outside the laboratory. “For industrial scale hydrogen production, we needed to set our study’s target current density to about 10 to 100 times higher than what has been used in past experiments,” says co-first author Shuang Kong. “The high currents led to a number of problems such as physical decomposition of the catalyst.”
Eventually, the team overcame these issues by trial and error, and discovered an active and stable catalyst by inserting manganese into the spinel lattice of Co3O4, producing the mixed cobalt manganese oxide Co2MnO4.
Sustainable Hydrogen Production
Testing showed that Co2MnO4 performed very well. Activation levels were close to those for state-of-the-art iridium oxides. Additionally, the new catalyst lasted over two months at a current density of 200 milliamperes per square centimeter, which could make it effective for practical use. Compared with other non-rare metal catalysts, which typically last only days or weeks at much lower current densities, the new electrocatalyst could be a game changer.
“We have achieved what has eluded scientists for decades,” says co-first author Ailong Li. “Hydrogen production using a highly active and stable catalyst made from abundant metals. In the long run, we believe that this is a huge step towards creating a sustainable hydrogen economy. Like other renewable technologies such as solar cells and wind power, we expect the cost of green hydrogen technology to plummet in the near future as more advances are made.”
The next step in lab will be to find ways to extend the lifetime of the new catalyst and increase its activity levels even more. “There is always room for improvement,” says Nakamura, “and we continue to strive for a non-rare metal catalyst that matches the performance of current iridium and platinum catalysts.”
Reference: “Enhancing the stability of cobalt spinel oxide towards sustainable oxygen evolution in acid” by Ailong Li, Shuang Kong, Chenxi Guo, Hideshi Ooka, Kiyohiro Adachi, Daisuke Hashizume, Qike Jiang, Hongxian Han, Jianping Xiao and Ryuhei Nakamura, 14 February 2022, Nature Catalysis.
DOI: 10.1038/s41929-021-00732-9
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8 Comments
Cobalt is not a “fairly common metal”. There’s a reason Tesla, Panasonic, and Samsung are abandoning it in their batteries. It’s a conflict mineral and its production is quite polluting to the environment.
Come up with something else.
Cobalt is not a rare element but while not rare in the earth crust is not that common. The controversity around Cobalt is more about how it’s mined , that the element per se, because most of the Cobalt is mined in the Republic of Congo where child labour and cheap but troublesome excavation techniques are used (e.g. explosive tunneling) making Cobalt mining more socially and environmentally impacting than mining more dangerous materials with the right equipment/personnel and with low impact mining.
The only irony is that we started industrially mining cobalt for the petrolchemical industry (that is still using fairly big chunck of the Cobalt mined) since circa 1950 and nobody cared a fig about it’s mining until EVs where it’s get even too much exposure , but now for hydrogen production is all fine an dandy.
west is now too worried about child labour. They did not think twice before rapping , killing and separating red indians in US and Canada and original inhabitants in Australia.
Use nuclear to power electrolysis to release h and O2, could spray ocean water in the skies instead of aluminum
The era of conflict cobalt and environmentally damaging cobalt mining is coming to an end thanks to new projects such as this one – https://www.abc.net.au/news/2022-03-02/cobalt-blue-s-project-given-national-significance-recognition/100874302
Australian Mines are also developing the Sconi cobalt-nickel-scandium mine in north Queensland
The thing that stands out to me is that they are introducing isocyanate that will form in polymer cells when exposed to moisture creating mic gas is why humanity is being groomed to stand toxic environment ,the only problem with it is another bhopal type explosion, and catastrophic type explosions if sparked at an accident and storage if exposed can level a suburb.never mind all the cancers that come hand in hand with being exposed to mic,isocyanate toxins just being in a garage with isocyanate,.please never use toxins for they are a forever isocyanate and can only lead to disaster.. like now isocyanate is covid19. And some misguided people think that we will become immune to it, WRONG ITS A FOREVER TOXIN WITH NO REVERSALthe world is being groomed for a catastrophic disaster. And the ozone will suffer from the afterburn please stop experimenting with humanity with something you can’t see or know it’s boundaries..it’s another bhopal waiting.
I agree with one of the other comments above. There is a reason battery manufacturerS are moving away from Cobalt. I don’t see how replacing 2 rare earth metals with Cobalt is a step forward. Hydrogen is a really poor fuel… period! It’s being highly promoted by fossil fuel companies and industries wishing to keep the fossil fuel business model in place, ie: you drive to a pump to fuel up, the fossil fuel companies produce, transport (truck or pipeline) and dictate the price of the fuel you will use. There are better ways.
The auto industry, specifically Toyota, has had 2 Hydrogen fuel based cars, they want and highly promote internal combustion engines, they also have to provide $15,000 worth of free hydrogen incentive for you to purchase a car that costs about the same as an electric, would cost the same to fuel as a gas or diesel vehicle (if you can find fueling stations nearby), and is still prone to the mechanical issues associated with internal combustion engines, not to mention that the performance is also less than a Battery Electric Vehicle.
I can only see Hydrogen being used by some heavy industries, where it will be produced and used at the source. No trucking, no pipeline across country, just made and used by say Steel or Aluminum manufacturers.
Still need hydrogen for rocket fuel.
Hydrogen for ICE cars is a loosing proposition.
Develop better battery technology and push EV