Hydrogen has long been the holy grail of clean energy. The problem up to this point has been that the only economically viable way to make it on an industrial scale was processing natural gas, hardly a green way to go. Another, greener way to create hydrogen is to make it from water using a electrolysis, a process which breaks water down into its component parts: oxygen and hydrogen by passing an electrical current through it. Conventional electrolysis methods are too expensive to make hydrogen fuel commercially viable. A team of scientists at Stanford University have just invented a new electrolysis technology for that could make hydrogen production inexpensive, inexpensive enough to make the switch from fossil fuels to hydrogen as the world's main fuel possible.
There are a number of aspects that make hydrogen so appealing as a fuel and/or an energy storage medium. It is clean burning. When you burn it, the only thing you get is water vapor. It is one of the most plentiful elements in the universe. Here on Earth you can make it from water. It's non-toxic, so if you had a breach of a fuel tank or a fuel cell, it would just become part of the air. It is also the perfect substance to use for fuel cells because, unlike, say, gasoline, there's only one element, so the process of chemically turning it into energy much simpler.
But so far there have been two main problems with electrolysis: it's expensive, and it's complicated. First of all, conventional electrolysis requires large amounts of electricity. Added to that cost is the cost of the the catalysts, metal elements that are the interface between the electricity and the water. They can only be made out of two expensive metals. Usually one is imbedded with platinum, and the other is embedded with iridium. The standard process also requires an expensive membrane between the two electrodes and an acid pH to be maintained in the water surrounding one electrode and an alkaline pH to be maintained around the other. The Stanford scientists have devised a low-cost electrolysis system that requires no membrane and uses a single catalyst to produce both hydrogen and oxygen requiring much less electricity than any other system so far.
Yi Cui, an associate professor of materials science and engineering at Stanford and of photon science at the SLAC National Accelerator Laboratory, is a member of the Stanford team and the co-author of a paper on the new device. "We have developed a low-voltage, single-catalyst water splitter that continuously generates hydrogen and oxygen for more than 200 hours," Cui says, "an exciting world-record performance."
After experimenting with lithium-ion battery technology, the Stanford team found that they could create a much more efficient electrolysis system that uses only one, much less expensive catalyst. "Our water splitter is unique," says Haotian Wang, another member of the Stanford team, and lead author of the paper on their efforts. "Because we only use one catalyst, nickel-iron oxide, for both electrodes,this bifunctional catalyst can split water continuously for more than a week with a steady input of just 1.5 volts of electricity. That's an unprecedented water-splitting efficiency of 82 percent at room temperature."
Wang and his colleagues have found that the nickel-iron oxide they use as their catalyst is not only, cheap and easy to produce, is actually far more stable than the catalysts made of precious metals used in most commercial electrolysis. So, if this technology pans out, and it there are no barriers to scaling it up to industrial levels, you may be filling up your car with hydrogen sooner than you thought.