Inexpensive Nanosheet Catalyst Splits Hydrogen From Water

An anonymous reader writes "Traditional methods of producing pure hydrogen are either extremely expensive or release lots of carbon dioxide into the atmosphere. Now, scientists at Brookhaven National Laboratory have developed an electrocatalyst that addresses one of these problems by generating hydrogen gas from water cleanly and with drastically more affordable materials. Goodbye platinum; hello nickel and ammonia."

That's not where most of the cost comes from

[Solandri]

I wouldn't have made this post a few weeks ago, but reading other people's comments about hydrogen fuel made it painfully obvious that many people have a fundamental misunderstanding about how the hydrogen economy works: There is no free energy. You cannot convert water into hydrogen with little energy, then burn the hydrogen with oxygen to get lots of energy.

The amount of energy you put in to break water into hydrogen and oxygen has to be more than the energy you get out when you burn (or combine via a fuel cell) the hydrogen with oxygen. There is no getting around this; it is simple thermodynamics. This is why many people refer to hydrogen as a battery, not as a fuel. Free hydrogen is exceptionally rare to find, so when you manufacture atomic hydrogen gas you're storing energy in it like in a battery. When you burn the hydrogen, you're extracting that energy like from a battery.

With electrolysis, typically you're looking at about 50%-70% of the energy you put in ending up in the hydrogen gas. The rest is converted into waste heat. With a non-research grade fuel cell, you're looking at about 50%-70% efficiency there as well (the rest going to waste heat). So for the cycle overall, you're at 25%-50% efficiency. That is, only 25%-50% of the energy you put in to create the hydrogen ends up actually doing useful work, which is absolutely abysmal for a battery.

The cost of materials like platinum is also a bit misleading. The platinum is not consumed during the electrolysis process. While the high cost of platinum does affect the cost of the device used to generate hydrogen, it has no effect on the cost of the hydrogen gas itself. Almost the entirety of the cost of hydrogen gas is the energy used to create it by cracking water.

Re:Will it work?

[Anonymous Coward]

Most people could care less about the future.

Couldn't care less.

Re:That's not where most of the cost comes from

[Grayhand]

Yes but the cost of Platinum has been holding back the wide adoption of fuel cell technology. At one point only NASA could aford to use them. Most of the cost of a fuel cell is in the platinum. Say you want or need to live off the grid, this process can make afordable equipment possible for producing hydrogen at home. You can use it to store energy for lean days or refuel the car. Not caustic and expensive batteries and the fuel cells can be recycled. Hydrogen was never a solution. Bush only pushed it after it was pointed out to him that most hydrogen in use now is produced from fossil fuel. How about this for crazy, install one on an offshore wind farm and run a pipe back to shore and have a wind farm producing not electricity but hydrogen gas! No line loss and you can have a car hydrogen fueling station on shore. Hydrogen does escape mostly at fitting and valves since it's so small it's nearly impossible to completely contain hydrogen but in a closed line there would be less loss than the bleed that happens in power lines which could offset some of the energy lost in producing the hydrogen.

Re:Will it work?

[BlueParrot]

Your way to do it probably had shitty efficiency. 1-2% of the electrical energy probably ended up used to produce hydrogen. With fancy catalysts and carefully controlled temperature, it's possible to improve that efficiency by a factor of 30 or so, with the best methods now getting efficiencies between 30 and 60%. The problem is that those schemes tend to either rely on very expensive catalysts (like platinum ), or they are chemical processes which produce CO2 as a by-product ( steam reforming, in which hydrocarbons are reacted with water to form hydrogen and CO2 ).

What the article seems to speak of is that they've found a catalyst that drastically improves the efficiency of electrolysis, without resorting to expensive materials.