Posted on 08/22/2014 10:51:36 AM PDT by Red Badger
In 2015, American consumers will finally be able to purchase fuel cell cars from Toyota and other manufacturers. Although touted as zero-emissions vehicles, most of the cars will run on hydrogen made from natural gas, a fossil fuel that contributes to global warming.
Now scientists at Stanford University have developed a low-cost, emissions-free device that uses an ordinary AAA battery to produce hydrogen by water electrolysis. The battery sends an electric current through two electrodes that split liquid water into hydrogen and oxygen gas. Unlike other water splitters that use precious-metal catalysts, the electrodes in the Stanford device are made of inexpensive and abundant nickel and iron.
"Using nickel and iron, which are cheap materials, we were able to make the electrocatalysts active enough to split water at room temperature with a single 1.5-volt battery," said Hongjie Dai, a professor of chemistry at Stanford. "This is the first time anyone has used non-precious metal catalysts to split water at a voltage that low. It's quite remarkable, because normally you need expensive metals, like platinum or iridium, to achieve that voltage."
In addition to producing hydrogen, the novel water splitter could be used to make chlorine gas and sodium hydroxide, another important industrial chemical, according to Dai. He and his colleagues describe the new device in a study published in the Aug. 22 issue of the journal Nature Communications.
The promise of hydrogen
Automakers have long considered the hydrogen fuel cell a promising alternative to the gasoline engine. Fuel cell technology is essentially water splitting in reverse. A fuel cell combines stored hydrogen gas with oxygen from the air to produce electricity, which powers the car. The only byproduct is water – unlike gasoline combustion, which emits carbon dioxide, a greenhouse gas.
Earlier this year, Hyundai began leasing fuel cell vehicles in Southern California. Toyota and Honda will begin selling fuel cell cars in 2015. Most of these vehicles will run on fuel manufactured at large industrial plants that produce hydrogen by combining very hot steam and natural gas, an energy-intensive process that releases carbon dioxide as a byproduct.
Splitting water to make hydrogen requires no fossil fuels and emits no greenhouse gases. But scientists have yet to develop an affordable, active water splitter with catalysts capable of working at industrial scales.
"It's been a constant pursuit for decades to make low-cost electrocatalysts with high activity and long durability," Dai said. "When we found out that a nickel-based catalyst is as effective as platinum, it came as a complete surprise."
Saving energy and money
The discovery was made by Stanford graduate student Ming Gong, co-lead author of the study. "Ming discovered a nickel-metal/nickel-oxide structure that turns out to be more active than pure nickel metal or pure nickel oxide alone," Dai said. "This novel structure favors hydrogen electrocatalysis, but we still don't fully understand the science behind it."
The nickel/nickel-oxide catalyst significantly lowers the voltage required to split water, which could eventually save hydrogen producers billions of dollars in electricity costs, according to Gong. His next goal is to improve the durability of the device.
"The electrodes are fairly stable, but they do slowly decay over time," he said. "The current device would probably run for days, but weeks or months would be preferable. That goal is achievable based on my most recent results."
The researchers also plan to develop a water splitter than runs on electricity produced by solar energy.
"Hydrogen is an ideal fuel for powering vehicles, buildings and storing renewable energy on the grid," said Dai. "We're very glad that we were able to make a catalyst that's very active and low cost. This shows that through nanoscale engineering of materials we can really make a difference in how we make fuels and consume energy."
Thanks for the information. One obvious drawback springs to mind.
Can the “hydrogen sponge” materials hold the same mass of hydrogen in an equivalent volume? Sounds to me like these storage mechanisms would likely be a lot more bulky. Of course, volume is one of the problems with hydrogen anyway.
“Actually, there is a real “flux capacitor”. And it looks nothing like that picture.”
Yeah, O’Reilly’s is probably just selling a cheap Chinese knockoff. A “frux crapacitor”.
A couple dozen volts from solar will be pretty easy to achieve. You could set up a splitter in your backyard that could generate enough gas tp power your car for the next day.
“Yeah, O’Reilly’s is probably just selling a cheap Chinese knockoff. A “frux crapacitor”.”
Milk out my nose.
Closer to 40 than 50 and only when running at optimum RPMs and doesn’t account for transmission losses and other loads not related to moving the vehicle such as pollution control.
Diesel locomotives are closest to ideal efficiency as the engine is not mechanically locked to the wheels letting them run at optimum RPMs and reduce transmission loss.
There are some power stations that can get about 50% efficiency but it requires space age materials to handle the heat as the efficiency is directly related to gas temp and ambient temp as described by Carnot.
Winner winner, chicken dinner.
But people are so lacking in science knowledge that they will lap this up just like the "200 MPG carburetor" and the "my car runs on water!" crap from the 70's & 80's.
Bulk is the problem in either case. The ‘sponge’ itself is bulky...................
“Milk out my nose.”
Milk is good for you. Used in moderation, of course.
The advantage would not be over all efficiency, it would be fuel flexibility. You can make electricity from many things other than imported oil.
I’m not a big hydrogen fan, to many obstacles to implementation.
“So is this a closed system, by which both the hydrogen and the oxygen would be captured and used to fuel an internal combustion engine?”
In a ‘perfect’ closed system you would generate Brown’s Gas and then immediately recombine the O and the 2 H’s in an internal combustion engine. Energy out is thus higher than energy in...
Ah, but the kicker here is it may make solar or wind generated electricity useful for something.
Natural Gas Power Density> 0.044 - 0.0562 /b/ft3
But you have to have a supply of natural gas. Hydrogen you can get anywhere.
I think this thing might make economic sense in some circumstances. I've been reading lately that the Navy now has the means to process ocean water into Aviation Fuel on their nuclear powered aircraft carriers. I think the fuel costs them something like $18.00 a gallon, but it become economically feasible as a result of their having the ability to make it whenever and wherever they need it instead of relying on logistical support to bring it.
Hydrogen splitting and storage would have to be used for some sort of similar need to make it economically viable, but I can see circumstances in which this could be true.
Also, your power densities for Hydrogen and for Natural Gas are at what pressures? Ambient?
What do they look like when pressurized to 3,600 psi as Natural Gas is normally?
Also is that energy density from burning or from Ionic transfer as with the Hydrogen?
Very interesting thing to notice. The reinventing of wheels via refinements of existing phenomena seems to happen a lot. Reversing things seems to be especially useful!
No, it doesn’t depend on how you measure the energy. In a reversible chemical reaction, like changing water to H and O, you can never get more energy out than was put in. It takes a certain amount of energy to break water into its components, and you get approximately the same energy back when you burn the hydrogen to produce water again.
As others have said, hydrogen is just a store of energy, not a source. It’s like a rechargeable battery: you have to put energy in to get energy out. There may be some situations where hydrogen is a more useful energy storage mechanism than, say, batteries, but they’re few and far between.
... unlike the “gas” stations that would be needed if you used hydrogen to fuel your vehicle. A car can transport far less energy as hydrogen than as gasoline, so a hydrogen-powered car will need to stop far more often for refueling.
Pressure on both figures were in lb/ft3
cubic lbs per ft.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.