Energy

New water-splitting process could kick-start "green" hydrogen economy

New water-splitting process co...
Researchers have come up with a cheaper, more efficient way to split hydrogen out of water
Researchers have come up with a cheaper, more efficient way to split hydrogen out of water
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Researchers have come up with a cheaper, more efficient way to split hydrogen out of water
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Researchers have come up with a cheaper, more efficient way to split hydrogen out of water

Australian scientists claim they've worked out a much cheaper, more efficient way to split hydrogen out of water, using easily sourced iron and nickel catalysts instead of expensive, rare ruthenium, platinum and iridium catalysts favored by current large-scale hydrogen producers, which are literally thousands of times more expensive.

Much is being made of the developing "hydrogen economy" idea, in which compressed hydrogen fuels will become an energy source as common as gasoline, and fuel cell cars will take a place alongside combustion engines and electric vehicles in the transport mix.

Yesterday, we wrote about the world's first liquid hydrogen transport ship, designed to take Australian-produced hydrogen across the water to be used in Japan as clean energy. Right now, though, Australia is producing hydrogen in one of the dirtiest possible ways: using brown coal, a process which requires 160 tonnes of coal to produce three tonnes of compressed liquid hydrogen, with a monstrous 100 tons of carbon dioxide as a by-product.

The "clean energy" hydrogen pie, particularly in Japan and Korea, is estimated to be worth trillions of dollars in the coming decades, so plenty of prospectors are smelling massive energy exporting opportunities, but realistically, until the math starts to stack up on greener ways of producing hydrogen, the environmental costs of producing this stuff in bulk could be overwhelming.

The "green" way to make hydrogen is to split it out of water using electrolysis. You put water in a container with a pair of electrodes in it, and apply power. Oxygen gathers at the anode, hydrogen at the cathode, and if the electricity you put into this process was sustainably generated, then congratulations, you've got yourself some properly green hydrogen – as long as you don't cart it around in diesel trucks and ships, and the energy you use to compress and super-cool it is green as well.

The trouble thus far has been that splitting water is expensive and inefficient, making it hard for green hydrogen to compete against brown hydrogen, or indeed gasoline. All of which makes this recent development from a research team spread across three major Australian universities – UNSW, Griffith and Swinburne – an interesting and significant one.

In a paper published in Nature Communications, the team said it had managed to replace the expensive platinum on the carbon catalyst using a "Janus nanoparticle catalyst with a nickel-iron oxide interface" – and that the resulting circuit had been able to split water with "to the best of our knowledge, the highest energy efficiency (83.7 percent) reported to date."

“What we do is coat the electrodes with our catalyst to reduce energy consumption,” says UNSW School of Chemistry’s Professor Chuan Zhao. “On this catalyst there is a tiny nano-scale interface where the iron and nickel meet at the atomic level, which becomes an active site for splitting water. This is where hydrogen can be split from oxygen and captured as fuel, and the oxygen can be released as an environmentally-friendly waste.”

“The nanoscale interface fundamentally changes the property of these materials,” he continues. “Our results show the nickel-iron catalyst can be as active as the platinum one for hydrogen generation. An additional benefit is that our nickel-iron electrode can catalyse both the hydrogen and oxygen generation, so not only could we slash the production costs by using Earth-abundant elements, but also the costs of manufacturing one catalyst instead of two."

It remains to be seen how this development could affect the cost of large-scale hydrogen production, but Zhao is highly optimistic: “We’ve been talking about the hydrogen economy for ages, but this time it looks as though it’s really coming.”

It also remains to be seen whether countries like Australia can get enough solar or wind power generators built to be exporters of truly "green" hydrogen at a scale that could make a meaningful dent in Tokyo or Seoul's smog levels. Or indeed if such export-hungry countries will regret shipping large amounts of their water overseas in the form of fuel. Until the rubber meets the road on an international hydrogen supply chain, a healthy degree of skepticism appears to be warranted.

Source: University of New South Wales

20 comments
George Kafantaris
“Until the rubber meets the road on an international hydrogen supply chain, a healthy degree of skepticism appears to be warranted.” Bologna. Not going to indulge the naysayers anymore -- done that long enough. Pedal to the metal and full speed ahead.
Magin Martin Louis Ongpin
I still believe using sunlight to produce formic acid from plastic, transport the formic acid which is liquid under normal condition and use the formic in fuel cells to produce electricity and rehydrogenate the carbon dioxide to make more formic acid is more energy efficient.
nick101
I worked in the 'hydrogen future' industry nearly 20 years ago, the challenges are still the same. Regardless of how you make it, hydrogen is impossible to compress without using a LOT of energy. The only practical use for hydrogen, is energy storage in huge tanks at the same p.s.i. as it comes out of whatever type of electrolizer (like the ones that use the process in this article) it's created with. Yet, somehow, nobody has hooked one up to the windmills that are expensive and impracticable.
Simon Redford
This is interesting, but existing electrolysis process claim around 80% conversion efficiency to hydrogen, so although a small efficiency improvement, the main saving will be lower cost catalysts. The use of compressed hydrogen in the future keeps coming up, but significant losses in compressing the hydrogen and the cost and safety implications of handling compressed hydrogen are likely to make it unrealistic as a transport fuel. For most applications it may be more realistic to look at renewable fuel distribution via synthetic fuels manufactured from renewable hydrogen or through direct renewable processes.
ei3io
I would agree that windmills in the ocean could create H2 possibly the cheapest day & night while also storing it plus the Oxygen in tanks below the water. There it may possibly be aided by the deepwater pressure where leaks would also show up quick as bubbles for repair. It then could be piped ashore or loaded onto cargo ships to distant user sites.
Colt12
Splitting hydrogen should be compared with producing gasoline. How much energy does it take to drill, pull the crude oil from the ground and truck it to the refiner. How much energy does it take for the refiner to separate and refine the gasoline product. The energy required to truck the gasoline to the storage yard, to have trucks filled and to deliver it to the stations. The pumps that get the gas from the underground tank to the consumers fuel tank.
FB36
It seems that some people unable to understand the total deal breaker problem w/ ALL hydrogen vehicles! It is NOT about cheap/easy production or storage of hydrogen! It is about massive explosive danger of hydrogen gas tanks everywhere!!! In the real world, there are traffic accidents & leakages & ruptures of gas tanks! & if those gas tanks are full of hydrogen then the result would NOT be fires; it would be endless massive explosions everywhere in the world!!!
GordonHoffman
I have wondered what hydrogen does in the upper atmosphere. If you have a billion hydrogen users spill a tiny amount everyday during refills, or little accidents? I've never heard any conjecture on the subject.
James Heartney
Unless someone has repealed the laws of physics, it still takes more energy to create hydrogen through electrolysis than you get back when you use it, either by burning or in a fuel cell. There are also losses due to compression, storage, transport, and decompression. In a few use cases, it might be worth it to deal with all these losses. But for most personal transport (cars and light trucks), you get far better efficiency, with much less mechanical complexity, by just using a battery. Charging times can take longer, but bear in mind that commercial hydrogen fueling stations are expensive, not as quick to fill as gasoline, often unreliable, and very scarce. OTOH electricity is everywhere.
Nobody
I have worked with hydrogen equipment for 30 years. It is the perfect fuel for the perfect situation. However, it is explosive in air anywhere from 10-90%. It embrittles metals. It can diffuse through containers. IT IS NOT A SUITABLE FUEL FOR VEHICLES. One leak at the wrong time would be far more hazardous than any fossil fuel. Even hydride storage has unacceptable risks. I am even more puzzled by those who want to turn electricity into hydrogen and then back again. There are safer ways to store electricity. What is theoretically possible and what is practical are two very different things.